ML21361A164

Research Information Letter Ril 2021-17, Report on High Energy Arcing Fault Experiments, Experimental Results from Low-Voltage Switchgear Enclosures (NIST Tn 2197)

ML21361A164
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Issue date:	12/31/2021
From:	Putorti A, Markhenry Salley, Gabe Taylor Office of Nuclear Regulatory Research, US Dept of Commerce, National Institute of Standards & Technology (NIST)
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NIST TN 2197 RIL 2021-17
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RIL 2021-17 NIST TN 2197 REPORT ON HIGH ENERGY ARCING FAULT EXPERIMENTS Experimental Results from Low-Voltage Switchgear Enclosures Date Published: December 2021 Prepared by:

G. Taylor Office of Nuclear Regulatory Research A.D. Putorti Jr.

National Institute of Standards and Technology Mark Henry Salley, NRC Project Manager

This report was published as National Institute of Standards and Technology (NIST) Technical Note 2197 as part of a series of experiments funded by the U.S. Nuclear Regulatory Commissions Office of Research. The report has been re-published as an NRC Research Information Letter (RIL).

Disclaimer Legally binding regulatory requirements are stated only in laws, NRC regulations, licenses, including technical specifications, or orders; not in Research Information Letters (RILs). A RIL is not regulatory guidance, although NRCs regulatory offices may consider the information in a RIL to determine whether any regulatory actions are warranted.

Certain commercial equipment, instruments, or materials are identified in this paper in order to specify the experimental procedure adequately. Such identification is not intended to imply recommendation or endorsement by the US Nuclear Regulatory Commission or the National Institute of Standards and Technology, or Sandia National Laboratories, nor is it intended to imply that the materials or equipment identified are necessarily the best available for the purpose.

NIST Technical Note 2197 Report on High Energy Arcing Fault Experiments Experimental Results from Low-Voltage Switchgear Enclosures Anthony Putorti Kenneth Hamburger Scott Bareham Nicholas Melly Christopher Brown Kenneth Miller Wai Cheong Tam Gabriel Taylor Edward Hnetkovsky U.S. Nuclear Regulatory Andre Thompson Commission Michael Selepak Philip Deardorff National Institute of Standards and Technology This publication is available free of charge from:

https://doi.org/10.6028/NIST.TN.2197 December 2021 U.S. Department of Commerce Gina M. Raimondo, Secretary National Institute of Standards and Technology James K. Olthoff, Performing the Non-Exclusive Functions and Duties of the Under Secretary of Commerce for Standards and Technology & Director, National Institute of Standards and Technology

Certain commercial entities, equipment, or materials may be identified in this document in order to describe an experimental procedure or concept adequately.

Such identification is not intended to imply recommendation or endorsement by the National Institute of Standards and Technology, nor is it intended to imply that the entities, materials, or equipment are necessarily the best available for the purpose.

National Institute of Standards and Technology Technical Note 2197 Natl. Inst. Stand. Technol. Tech. Note 2197, 531 pages (December 2021)

CODEN: NTNOEF This publication is available free of charge from:

https://doi.org/10.6028/NIST.TN.2197

Abstract This report documents an experimental program designed to investigate High Energy Arcing Fault (HEAF) phenomena for low-voltage metal enclosed switchgear containing aluminum conductors. This report covers full-scale laboratory experiments using representative nuclear power plant (NPP) three-phase electrical equipment. Electrical, thermal, and pressure data were recorded for each experiment and documented in this report. This report covers experiments performed on two low-voltage switchgear units with each unit consisting of two vertical sections. The data collected supports characterization of the low-voltage HEAF hazard, and these results will be used to support potential improvements in fire probabilistic This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 risk assessment (PRA) methods.

The experiments were performed at KEMA Labs located in Chalfont, Pennsylvania. The experimental design, setup, and execution were completed by staff from the NRC, the National Institute of Standards and Technology (NIST), Sandia National Laboratories (SNL) and KEMA. In addition, representatives from the Electric Power Research Institute (EPRI) observed some of the experimental setup and execution.

The HEAF experiments were performed between August 26 and August 29, 2019 on near-identical Westinghouse Type DS low-voltage metal-enclosed indoor switchgear. A three-phase arcing fault was initiated on the aluminum main bus or in select cases on the copper bus stabs near the breaker. These experiments used either nominal 480 V (AC) or 600 V (AC). Durations of the experiments ranged from approximately 0.4 s to 8.3 s with fault currents ranging from approximately 9.2 kA to 19.3 kA. Real-time electrical operating conditions, including voltage, current, and frequency, were measured during the experiments.

Heat fluxes and incident energies were measured with plate thermometers, radiometers, and slug calorimeters at various locations around the electrical enclosures. Environmental measurements of breakdown, conductivity, and electromagnetics were also taken. The experiments were documented with normal and high-speed videography, infrared imaging, and photography.

The results, while limited, indicated the difficulty in maintaining and sustaining low-voltage arcs on aluminum components of sufficient duration and at a single point as observed from operating experience [1].

Key words High Energy Arcing Fault, Arc Flash, Electrical Enclosure, Electric Arc, Fire Probabilistic Risk Assessment i

Table of Contents Introduction ..................................................................................................................... 1 1.1. Background ................................................................................................................. 1 1.2. Objectives .................................................................................................................... 2 1.3. Scope ........................................................................................................................... 2 1.4. Approach ..................................................................................................................... 2 EXPERIMENTAL METHOD ....................................................................................... 2 This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 2.1. Experiment Planning ................................................................................................... 3 2.2. Experiment Facility ..................................................................................................... 3 2.3. Test Device .................................................................................................................. 6 2.4. Instrumentation ............................................................................................................ 9 2.4.1. Photometrics ........................................................................................................ 12 2.4.2. High-Definition Videography ............................................................................. 13 2.4.3. Thermography ..................................................................................................... 13 2.4.4. Calorimetry .......................................................................................................... 17 2.4.5. Pressure Transducer ............................................................................................ 23 2.4.6. Auxiliary Measurements ..................................................................................... 25 2.4.7. Mass Loss Measurements .................................................................................... 25 2.4.8. Electrical Data Acquisition and Processing ........................................................ 25 2.4.9. Cable Samples ..................................................................................................... 26 2.4.10. Instrument Deployment ....................................................................................... 28 Experimental Results .................................................................................................... 41 3.1. Test 2-13A - 480 V, 13.5 kA, 2 s duration, main bus top load section .................... 43 3.1.1. Observations ........................................................................................................ 43 3.2. Test 2-13B - 600 V, 13.5 kA, 2 s duration, main bus top load section..................... 50 3.2.1. Observations ........................................................................................................ 51 3.3. Test 2-13C - 600 V, 13.5 kA, 2 s duration, main bus top load section..................... 58 3.3.1. Observations ........................................................................................................ 59 3.4. Test 2-13D - 600 V, 13.5 kA, 2 s duration, breaker stabs (copper) top load section 66 3.4.1. Observations ........................................................................................................ 67 3.5. Test 2-13E - 600 V, 13.5 kA, 2 s duration, breaker stabs (copper) middle breaker cubicle ................................................................................................................................. 75 3.5.1. Observations ........................................................................................................ 76 3.6. Test 2-13F - 480 V, 13.5 kA, 2 s duration, main bus, load section .......................... 85 ii

3.6.1. Observations ........................................................................................................ 85 3.7. Test 2-13G - 600 V, 13.5 kA, 2 s duration, main bus, Supply section ..................... 94 3.7.1. Observations ........................................................................................................ 94 3.8. Test 2-18A - 480 V, 25 kA, 8 s duration, main bus, load section .......................... 101 3.8.1. Observations ...................................................................................................... 102 3.9. Test 2-18B - 600 V, 25 kA, 8 s duration, main bus, supply section ....................... 111 3.9.1. Observations ...................................................................................................... 112 This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Summary and Conclusion ........................................................................................... 123 4.1. Summary ................................................................................................................. 123 4.2. Conclusions ............................................................................................................. 125 References ............................................................................................................................ 127 Appendix A: Engineering Drawings ................................................................................. 129 A.1 Experimental Facility .............................................................................................. 129 A.2 Support Drawings .................................................................................................... 132 Appendix B: Electrical Measurement ............................................................................... 138 Appendix C: KEMA Test Report ...................................................................................... 157 iii

List of Tables Table 1. Experimental Matrix Low-voltage DS Switchgear Experiments............................... 9 Table 2. List of measurement equipment. .............................................................................. 10 Table 3. Expanded uncertainty for IR imager temperatures .................................................. 15 Table 4. Manufacturers' descriptions of the cables used in the experiments. ........................ 26 Table 5. Nominal cable properties. ........................................................................................ 26 Table 6. Circuit Calibration. Measurements are +/- 3 percent. ................................................ 41 Table 7. Summary of LV switchgear experiments ................................................................. 42 Table 8. Observations from Test 2-13A ................................................................................. 44 This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Table 9. Summary of plate thermometer measurements Test 2-13A ..................................... 47 Table 10. Summary of Tcap slug measurements, Test 2-13A. ................................................ 48 Table 11. Key measurement from Test 2-13A. Measurement uncertainty +/- 3 percent. ........ 50 Table 12. Observations from Test 2-13B ............................................................................... 51 Table 13. Summary of plate thermometer measurements Test 2-13B. .................................. 54 Table 14. Summary of ASTM slug calorimeter measurements, Test 2-13B. ........................ 55 Table 15. Summary of Tcap slug measurement, Test 2-13B. .................................................. 55 Table 16. Key measurement from Test 2-13B. Measurement uncertainty +/- 3 percent. ........ 57 Table 17. Observations from Test 2-13C. .............................................................................. 59 Table 18. Summary of plate thermometer measurements Test 2-13C. .................................. 62 Table 19. Summary of ASTM slug calorimeter measurements, Test 2-13C. ........................ 64 Table 20. Summary of Tcap slug measurement, Test 2-13C. .................................................. 64 Table 21. Key measurement from Test 2-13C. Measurement uncertainty +/- 3 percent. ........ 66 Table 22. Observations from Test 2-13D. .............................................................................. 68 Table 23. Summary of plate thermometer measurements Test 2-13D. .................................. 72 Table 24. Summary of ASTM slug calorimeter measurements, Test 2-13D. ........................ 73 Table 25. Summary of Tcap slug measurement, Test 2-13D................................................... 73 Table 26. Key measurement from Test 2-13D. Measurement uncertainty +/- 3 percent. ........ 75 Table 27. Observations from Test 2-13E. .............................................................................. 77 Table 28. Summary of plate thermometer measurements Test 2-13E. .................................. 81 Table 29. Summary of ASTM slug calorimeter measurements, Test 2-13E. ........................ 82 Table 30. Summary of Tcap slug measurement, Test 2-13E. .................................................. 83 Table 31. Key measurement from Test 2-13E. Measurement uncertainty +/- 3 percent. ......... 84 Table 32. Observations from Test 2-13F. .............................................................................. 86 Table 33. Summary of plate thermometer measurements Test 2-13F. .................................. 90 Table 34. Summary of ASTM slug calorimeter measurements, Test 2-13F.......................... 91 Table 35. Summary of Tcap slug measurement, Test 2-13F. .................................................. 91 Table 36. Key measurement from Test 2-13F. Measurement uncertainty +/- 3 percent. ......... 93 Table 37. Observations from Test 2-13G. .............................................................................. 95 Table 38. Summary of plate thermometer measurements Test 2-13G. .................................. 98 Table 39. Summary of ASTM slug calorimeter measurements, Test 2-13G. ........................ 99 Table 40. Summary of Tcap slug measurement, Test 2-13G. ................................................ 99 Table 41. Key measurement from Test 2-13G. Measurement uncertainty +/- 3 percent. ...... 101 Table 42. Observations from Test 2-18A. ............................................................................ 103 Table 43. Summary of plate thermometer measurements Test 2-18A. ................................ 107 Table 44. Summary of ASTM slug calorimeter measurements, Test 2-18B. ...................... 108 Table 45. Summary of Tcap slug measurement, Test 2-18A................................................. 109 iv

Table 46. Key measurement from Test 2-18A. Measurement uncertainty +/- 3 percent. ...... 111 Table 47. Observations from Test 2-18A. ............................................................................ 113 Table 48. Summary of plate thermometer measurements Test 2-18B. ................................ 118 Table 49. Summary of ASTM slug calorimeter measurements, Test 2-18B. ...................... 119 Table 50. Summary of Tcap slug measurement, Test 2-18B. .............................................. 120 Table 51. Key measurement from Test 2-18B. Measurement uncertainty +/- 3 percent. ...... 122 Table 52. Experiment Summary........................................................................................... 123 Table 53. Summary of maximum incident energy measurements. ...................................... 124 This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 v

List of Figures Fig. 1. Graphical Phase 2 Experimental Matrix for Electrical Enclosure ............................... 3 Fig. 2. Isometric drawing of Test Cell #7 (left) and Location of Test Cell #7 with respect to KEMA facility (right). .............................................................................. 5 Fig. 3. Isometric drawing of low-voltage metal enclosed switchgear. .................................... 7 Fig. 4. Drawing of DS Switchgear as procured (all drawing dimensions in "centimeters") ........................................................................................................... 8 Fig. 5. Photo of DS switchgear. (front (left); side and front (center); opposite side (right)). ...................................................................................................................... 8 This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Fig. 6. Plan view of SNL instrumentation locations (note that locations are approximate, and instruments used varied by experiment. Illustration is not to scale). See details in Appendix A.2. ............................................................. 11 Fig. 7. Photograph of instrumentation cluster (from Left-to-right, air breakdown, radiometer, d-dot, air conductivity, high speed IR and visible videography .......... 12 Fig. 8. Thermal imagers (NIST thermal imaging cameras located approximately 26.5 m from test device (let), SNL imaging cameras located approximately 27 m from test device (right), from left to right (thermal, high speed visible, thermal)) ..................................................................................................... 15 Fig. 9. Thermal imagers and high speed imagers are located in the courtyard. Four NIST cameras are in structure, approximately 26.5 m from the test device.

Two SNL cameras are located outside the structure, approximately 27.0 m from the test device. ................................................................................................ 16 Fig. 10. Plan view of NIST and SNL camera locations (not to scale). .................................. 16 Fig. 11. Exploded view of modified plate thermometer (left); Cross-sectional view of modified plate thermometer placed on cone calorimeter sample holder (right). ..................................................................................................................... 17 Fig. 12. Cross-section of ASTM Slug (top) nominal dimensions in millimeters, photo of device being prepared in the field (bottom). Note that the two bolts on each side of the device are used for mounting to the DIN rail of the instrumentation rack. ......................................................................................... 20 Fig. 13. Thermal capacitance style slug, illustration (top left), photo of device being prepared in the field (top right), dimensional drawings showing internal construction (bottom left and right). All dimensions in mm. ................................. 22 Fig. 14. Data Acquisition System Configuration with EMI rejection. .................................. 23 Fig. 15. Photos of pressure measurement locations (PT3 and PT4 (left); PT1 and PT2 (right)). ............................................................................................................ 24 Fig. 16. Drawings showing locations of pressure sensor devices.......................................... 25 Fig. 17. Cable coupon constructed of seven conductor PE / PVC control cable (Cable 900). Front view. ......................................................................................... 27 Fig. 18. Cable coupon constructed of seven conductor PE / PVC control cable (Cable 900). Side view. .......................................................................................... 27 Fig. 19. Elevation view of instrument rack configuration around electrical enclosure for Test 2 13A through 2 13G. Dimensions in mm. ............................................... 28 Fig. 20. Plan view of instrument rack configuration around electrical enclosure for Test 2-13A through 2-13G. Dimensions in mm. The switchgear enclosure vi

is approximately 1.080 m (42.5 in) wide, 1.708 m (67.3 in) deep, and 2.337 m (92.0 in) tall............................................................................................... 29 Fig. 21. Elevation view of instrument rack configuration around electrical enclosure for Test 2-18A and 2-18B. Dimensions in mm....................................................... 30 Fig. 22. Plan view of instrument rack configuration around electrical enclosure for Test 2 18A and 2-18B. The enclosure is approximately 1.080 m (42.5 in) wide, 1.708 m (67.3 in) deep, and 2.337 m (92.0 in) tall........................................ 31 Fig. 23. Illustration of Vertical Instrumentation Rack 1 with data acquisition channels . Dimensions in mm +/- 5 mm.................................................................... 32 Fig. 24. Detailed Horizontal Locations of Instruments on Instrument Racks 1, 2, 3, This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 4, 5, and 6. Dimensions in mm +/- 5 mm. ................................................................. 33 Fig. 25. Illustration of Vertical Instrumentation Rack 2 with data acquisition channels. Dimensions in mm +/- 5 mm..................................................................... 34 Fig. 26. Illustration of Vertical Instrumentation Rack 3 with data acquisition channels. Dimensions in mm +/- 5 mm..................................................................... 35 Fig. 27. Illustration of Horizontal Instrumentation Rack 4 with data acquisition channels. Dimensions in mm +/- 5 mm. Rack was installed so that the sensors are located approximately 0.91 m (3.00 ft) from the top of the enclosure metal cladding......................................................................................... 36 Fig. 28. Illustration of Horizontal Instrumentation Rack 5 with data acquisition channels. Dimensions in mm +/- 5 mm. Rack was installed so that the sensors are located approximately 1.83 m (6.00 ft) from the top of the enclosure metal cladding......................................................................................... 37 Fig. 29. Illustration of Vertical Instrumentation Rack 6 with data acquisition channels. Dimensions are the same as Instrument Racks 1, 2, 3, 4, and 5.

Note that this rack was rotated clockwise 90 degrees as shown on left bottom. .................................................................................................................... 38 Fig. 30. Photo of Instrumentation Racks for Test 2-13A through Test 2-13G. ..................... 39 Fig. 31. Photo of Instrumentation Racks for Test 2-18A Test 2-18B.................................... 40 Fig. 32. Shorting wire location Test 2-13A (Phases left-to-right: A-B-C), photo of arc initiation point (left), elevation view (center), plan view (right).

Shorting location shown in red on illustrations. ..................................................... 43 Fig. 33. Sequence of Images from Test 2-13A (image time stamps are in seconds)............. 45 Fig. 34. Enclosure Post-Test 2-13A. ...................................................................................... 46 Fig. 35. Pressure measurements from Test 2-13A (breaker compartment (left); Main bus [arcing compartment] - (right)). Measurement uncertainty +/- 3 percent. ......... 49 Fig. 36. Shorting wire location Test 2-13B (Phases left-to-right: A-B-C), photo of arc initiation point (left), elevation view (center), Plan View (right).

Shorting location shown in red on illustrations. ..................................................... 50 Fig. 37. Sequence of Images from Test 2-13B (image time stamps are in seconds). ............ 52 Fig. 38. Enclosure Post-Test 2-13B. ...................................................................................... 53 Fig. 39. Pressure measurements from Test 2-13B (breaker compartment (left); Main bus [arcing compartment] (right). Measurement uncertainty +/- 3 percent. ............. 57 Fig. 40. Shorting Wire Location Test 2-13C (Phases left-to-right: A-B-C) (top left);

grounding plate (top right); illustration of shorting wire (red) and vii

grounding plate (blue) locations (bottom left) elevation view and plan view (bottom right). ................................................................................................ 58 Fig. 41. Sequence of Images from Test 2-13C (image time stamps are in seconds). ............ 60 Fig. 42. Enclosure Post-Test 2-13C. Top photo showing top of vertical main buses.

Bottom photo. ......................................................................................................... 61 Fig. 43. Pressure measurements from Test 2-13C (breaker compartment (left); Main bus [arcing compartment] (right). Measurement uncertainty +/- 3 percent. ............. 65 Fig. 44. Shorting Wire Location Test 2-13D (Phases left-to-right: A-B-C), photo of arc initiation point (left), elevation view (center), plan view (right).

Shorting location shown in red on illustrations. ..................................................... 67 This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Fig. 45. Sequence of Images from Test 2-13D (image time stamps are in seconds)............. 69 Fig. 46. Enclosure Post-Test 2-13D. ...................................................................................... 70 Fig. 47. Thermal heating on external of load section enclosure adjacent to top of vertical bus bars. ..................................................................................................... 71 Fig. 48. Pressure measurements from Test 2-13D (breaker compartment (left); Main bus [arcing compartment] (right). Measurement uncertainty +/- 3 percent. ............. 74 Fig. 49. Shorting Wire Location Test 2-13E (Phases left-to-right: A-B-C), photo of arc initiation point (left), elevation view (center), plan view (right).

Shorting location shown in red on illustrations. ..................................................... 76 Fig. 50. Sequence of Images from first have of Test 2-13E (image time stamps are in seconds). ............................................................................................................. 77 Fig. 51. Sequence of Images from second half of Test 2-13E (image time stamps are in seconds)......................................................................................................... 78 Fig. 52. Switchgear stabs post-experiment. ........................................................................... 79 Fig. 53. Breaker post-experiment. (front/side view (left), top/rear view showing breaker contact fingers missing (right)). ................................................................. 79 Fig. 54. Main bus bar post-experiment. ................................................................................. 80 Fig. 55. Pressure measurements from Test 2-13E (breaker compartment (left); Main bus [arcing compartment] (right). Measurement uncertainty +/- 3 percent. ............. 84 Fig. 56. Shorting Wire Location Test 2-13F (Phases left-to-right: A-B-C), photo of arc initiation point (left), elevation view (center), plan view (right).

Shorting location shown in red on illustrations. ..................................................... 85 Fig. 57. Sequence of Images from Test 2-13F (image time stamps are in seconds). ............ 87 Fig. 58. Enclosure Post-Test 2-13F. ...................................................................................... 88 Fig. 59. Post-experiment image of enclosure grounding cable disconnected from enclosure due to current flow through ground circuit............................................. 89 Fig. 60. Pressure measurements from Test 2-13F (breaker compartment (left); Main bus [arcing compartment] - (right)). Measurement uncertainty +/- 3 percent. ......... 93 Fig. 61. Shorting Wire Location Test 2-13G (Phases left-to-right: A-B-C), photo of arc initiation point (left), elevation view (center), plan view (right).

Shorting location shown in red on illustrations. ..................................................... 94 Fig. 62. Sequence of Images from Test 2-13G (image time stamps are in seconds)............. 96 Fig. 63. Enclosure Post-Test 2-13G. ...................................................................................... 97 Fig. 64. Pressure measurements from Test 2-13G (breaker compartment (left); Main bus [arcing compartment] - (right)). Measurement uncertainty +/- 3 percent. ....... 100 viii

Fig. 65. Shorting Wire Location Test 2-18A (Phases left-to-right: A-B-C), photo of arc initiation point (left), elevation view (center), plan view (right).

Shorting location shown in red on illustrations. ................................................... 102 Fig. 66. Sequence of Images from Test 2-18A up to 0.617 s (image time stamps are in seconds). ........................................................................................................... 104 Fig. 67. Sequence of Images from Test 2-18A from 0.617 s to end of experiment (image time stamps are in seconds). ..................................................................... 105 Fig. 68. Enclosure Post-Test 2-18A. Top of main bus, Load side (left), supply side (right). ................................................................................................................... 105 Fig. 69. Post-experiment image of enclosure breach and thermal effects on supply This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 side of gear. ........................................................................................................... 106 Fig. 70. Pressure measurements from Test 2-18A (breaker compartment (left); Main bus [arcing compartment] - (right)). Measurement uncertainty +/- 3 percent. ....... 110 Fig. 71. Shorting Wire Location Test 2-18B (Phases left-to-right: A-B-C) (top left);

grounding plate (top right); illustration of shorting wire (red) and grounding plate (blue) locations elevation view (bottom left) and plan view (bottom right). .............................................................................................. 112 Fig. 72. Sequence of Images from Test 2-18B up to 4.671 s (image time stamps are in seconds). ........................................................................................................... 114 Fig. 73. Sequence of images from TEst 2-18B from 4.671 s (image time stamps are in seconds). ........................................................................................................... 115 Fig. 74. Enclosure Post-Test 2-18B. load section (left), supply section (right)). ................ 116 Fig. 75. Post-experiment image of enclosure. (load side (left), supply side (right)). .......... 116 Fig. 76. Failure of KEMA cable connection observed as arcing occurring in Cell 8 (non-test cell). ....................................................................................................... 117 Fig. 77. Pressure measurements from Test 2-18B (breaker compartment (left); Main bus [arcing compartment] - (right)). Measurement uncertainty +/- 3 percent. ....... 121 Fig. 78. Isometric drawing of Test Cell #7. ......................................................................... 129 Fig. 79. Plan view of Test Cell #7. Low-voltage power connections located on right side of drawing. ..................................................................................................... 130 Fig. 80. Elevation view of Test Cell #7. Low-voltage power connections located on right side of drawing. ............................................................................................ 131 Fig. 81. Drawing KPT-MB-4657, ASTM Calorimeter Assembly. ..................................... 133 Fig. 82. Drawing KPT-MA-4599, ASTM Calorimeter Cup. .............................................. 134 Fig. 83. Isometric drawings of LV metal enclosed indoor switchgear. ............................... 135 Fig. 84. Plan and elevation drawings of LV metal enclosed indoor switchgear. ................ 136 Fig. 85. Drawing of interior layout of LV metal enclosed indoor switchgear..................... 137 Fig. 86. Voltage and Current Profile during Test 2-13A. Measurement uncertainty +/-

3 percent. ............................................................................................................... 139 Fig. 87. Transient current profiles for Test 2-13A. Measurement uncertainty +/- 3 percent. .................................................................................................................. 140 Fig. 88. Power and Energy for Test 2-13A. Measurement uncertainty +/- 3 percent. ........... 140 Fig. 89. Voltage and Current Profile during Test 2-13B. Measurement uncertainty +/-

3 percent. ............................................................................................................... 141 Fig. 90. Transient current profiles for Test 2-13B. Measurement uncertainty +/- 3 percent. .................................................................................................................. 142 ix

Fig. 91. Power and Energy for Test 2-13B. Measurement uncertainty +/- 3 percent. ........... 142 Fig. 92. Voltage and Current Profile during Test 2-13C. Measurement uncertainty +/-

3 percent. ............................................................................................................... 143 Fig. 93. Transient current profiles for Test 2-13C. Measurement uncertainty +/- 3 percent. .................................................................................................................. 144 Fig. 94. Power and Energy for Test 2-13C. Measurement uncertainty +/- 3 percent. ........... 144 Fig. 95. Voltage and Current Profile during Test 2-13D. Measurement uncertainty +/-

3 percent. ............................................................................................................... 145 Fig. 96. Transient current profiles for Test 2-13D. Measurement uncertainty +/- 3 percent. .................................................................................................................. 146 This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Fig. 97. Power and Energy for Test 2-13D. Measurement uncertainty +/- 3 percent. ........... 146 Fig. 98. Voltage and Current Profile during Test 2-13E. Measurement uncertainty +/-

3 percent. ............................................................................................................... 147 Fig. 99. Transient current profiles for Test 2-13E. Measurement uncertainty +/- 3 percent. .................................................................................................................. 148 Fig. 100. Power and Energy for Test 2-13E. Measurement uncertainty +/- 3 percent. ......... 148 Fig. 101. Voltage and Current Profile during Test 2-13F. Measurement uncertainty

+/- 3 percent............................................................................................................. 149 Fig. 102. Transient current profiles for Test 2-13F. Measurement uncertainty +/- 3 percent. .................................................................................................................. 150 Fig. 103. Power and Energy for Test 2-13F. Measurement uncertainty +/- 3 percent. .......... 150 Fig. 104. Voltage and Current Profile during Test 2-13G. Measurement uncertainty

+/- 3 percent............................................................................................................. 151 Fig. 105. Transient current profiles for Test 2-13G. Measurement uncertainty +/- 3 percent. .................................................................................................................. 152 Fig. 106. Power and Energy for Test 2-13G. Measurement uncertainty +/- 3 percent. ......... 152 Fig. 107. Voltage and Current Profile during Test 2-18A. Measurement uncertainty

+/- 3 percent............................................................................................................. 153 Fig. 108. Transient current profiles for Test 2-18A. Measurement uncertainty +/- 3 percent. .................................................................................................................. 154 Fig. 109. Power and Energy for Test 2-18A. Measurement uncertainty +/- 3 percent. ......... 154 Fig. 110. Voltage and Current Profile during Test 2-18B. Measurement uncertainty

+/- 3 percent............................................................................................................. 155 Fig. 111. Transient current profiles for Test 2-18B. Measurement uncertainty +/- 3 percent. .................................................................................................................. 156 Fig. 112. Power and Energy for Test 2-18B. Measurement uncertainty +/- 3 percent. ......... 156 x

EXECUTIVE

SUMMARY

PRIMARY AUDIENCE: Fire protection, electrical, and probabilistic risk assessment engineers conducting or reviewing fire risk assessments related to high energy arcing faults.

SECONDARY AUDIENCE: Engineers, reviewers, utility managers, and other stakeholders who conduct, review, or manage fire protection programs and need to understand the underlying technical basis for the hazards associated with high energy arcing faults.

KEY RESEARCH QUESTION: How do aluminum components involved in high energy arcing faults influence the hazard to external targets?

This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 RESEARCH OVERVIEW Operating experience has shown that high energy arcing faults pose a hazard to the safe operation of nuclear facilities. Current regulations and probabilistic risk assessment methods were developed using limited information, and these uncertainties required the use of safety margins to bound the hazard. Experiments aimed at providing additional data to improve realism identified a concern that high energy arcing faults involving aluminum may increase the hazard potential. Due to the limited number of experiments where this phenomenon was observed, the NRC pursued additional experimental studies focused on assessing the specific impact of aluminum on the hazard. This report documents a set of experiments performed in 2019.

A series of low-voltage metal enclosed indoor switchgear arcing experiments were performed. Each experiment consisted of an arcing fault initiated within the switchgear unit on either the aluminum main bus work or the copper bus stabs. Numerous measurements were taken to characterize the environment within and surrounding the box, including external heat flux, external incident energy, electromagnetic field, air conductivity, and air breakdown strength. Time resolved electrical measurements of the fault conditions were also recorded.

This report documents the experiments performed, including the experimental methods, test facility, test device, instrumentation, observations, and results. Videos and photometric data files are provided by laboratories contracted to the NRC, and information on accessing that information is identified. This report does not provide detailed evaluation of the results or comparisons of the results to other methods or data. Those efforts will be documented in subsequent report(s).

KEY FINDINGS This research yields a data set of information to characterize the effects of electrical arcing faults involving aluminum electrodes. The results from this research include:

• Low-voltage arc faults were difficult to sustain in the configurations studied.

• Arc migration away from the initiation point was evident in several of the experiments and consistent with observations from Phase 1 testing [2]. The inability to sustain the arc in one location reduces the possibility of breaching the enclosure and exposing external targets to HEAF-generated thermal energy.

xi

• Sustaining an arc on copper bus bars was easier than on aluminum bus bars, even though the phase-to-phase separation distances are larger for copper than aluminum buses. The location of the arc for the copper experiments and internal combustible materials resulted in an ensuing fire which required manual intervention to extinguish.

• Measured pressure increases within the enclosure were small and didnt result in deformation of the enclosure panels or cause doors to open.

• Air conductivity and breakdown strength measurements were made during a number This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 of experiments. For the experimental conditions and locations investigated, the results indicated that the conductive cloud was unlikely to cause equipment arc over.

• For the experimental conditions and locations investigated, the electromagnetic interference measurements showed that the EMI signature was small and not likely to impact sensitive plant equipment.

WHY THIS MATTERS This report provides empirical evidence to assist U.S. NRC staff and stakeholders who are evaluating the adequacy of current methods. The information provided will support advances in state-of-the-art methods and tools to assess the high energy arcing fault hazard in nuclear facilities. This information may also be applicable to fossil fuel and alternative energy facilities and other buildings with low and medium voltage electrical distribution equipment such as switchgear and bus ducts.

HOW TO APPLY RESULTS Engineers and scientist advancing hazard and fire probabilistic risk assessment methods should focus on Section 3 and 4 of this report.

LEARNING AND ENGAGEMENT OPPORTUNITIES Users of this report may be interested in the following opportunities:

Nuclear Energy Agency (NEA) HEAF Project to conduct experiments in order to explore the basic configurations, failure modes and effects of HEAF events. Primary objectives include (1) development of a peer-reviewed guidance document that could be readily used to assist regulators of participants and (2) joint nuclear safety project report covering all experimentation and data captured. More information on the project and opportunities to participate in the program can be found online at https://www.oecd-nea.org/.

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CITATIONS This report was prepared by the following:

National Institute of Standards and Technology (NIST)

Engineering Laboratory; Fire Research Division Gaithersburg, Maryland 20899 Anthony D. Putorti Jr.

Scott Bareham Christopher Brown This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Wai Cheong Tam Edward Hnetkovsky Andre Thompson Michael Selepak Phil Deardorff U.S. Nuclear Regulatory Commission Washington, DC 20555-0001 Kenneth Hamburger Nicholas Melly Kenneth Miller Gabriel Taylor xiii

ABBREVIATIONS AND ACRONYMS AC alternating current ASTM American Society of Testing and Materials AWG American Wire Gauge DAQ data acquisition DC direct current DIN Deutsches Institut für Normung EMI electro-magnetic interference EPRI Electric Power Research Institute This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 GI generic issue GIRP Generic Issue Review Panel HEAF high energy arcing fault HD high definition IEEE Institute of Electrical and Electronic Engineers IN information notice IR infra-red MD management directive NEA Nuclear Energy Agency NEC National Electric Code NIST National Institute of Standards and Technology NRC Nuclear Regulatory Commission OECD Organisation for Economic Co-operation and Development PIRT Phenomena Identification and Ranking Table PRA probabilistic risk assessment PT plate thermometer RES Office of Nuclear Regulatory Research RIL research information letter SNL Sandia National Laboratories U.S. United States of America xiv

Introduction Infrequent events such as fires at a nuclear power plant can pose a significant risk to safe plant operations. Licensees combat this risk by having robust fire protection programs designed to minimize the likelihood and consequences of fire. These programs provide reasonable assurance of adequate protection from known fire hazards. However, several hazards remain subject to a larger degree of uncertainty, requiring significant safety margins in plant analyses.

One such hazard comprises an electrical arcing fault involving electrical distribution equipment and components comprised of aluminum. While the electrical faults and subsequent fires are This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 considered in existing fire protection programs, recent research [1] has indicated that the presence of aluminum during the electrical fault can exacerbate the damage potential of the event. The extended damage capacity could exceed the protection provided by existing fire protection features for specific fire scenarios and increase plant risk estimated in fire probabilistic risk assessments (PRAs).

The U.S. Nuclear Regulatory Commission (NRC) Office of Nuclear Regulatory Research (RES) studies fire and explosion hazards to ensu the safe operation of nuclear facilities. This includes developing data, tools, and methodologies to support risk and safety assessments. Through recent research efforts and collaboration with international partners, a non-negligible number of reportable high energy arcing fault (HEAF) events have been identified as occurring in nuclear facilities [3]. HEAF events pose a unique hazard in nuclear facilities and additional research in this area is needed to ensure that the hazard is accurately characterized and assessed for its impact on nuclear safety.

1.1. Background In June 2013, an OECD/NEA report [1] on international operating experience documented 48 HEAF events, accounting for approximately 10 % of the total fire events reported. These HEAF events are often accompanied by loss of essential power and complicated shutdowns. Existing PRA methodology for HEAF analysis is prescribed in NUREG/CR-6850 EPRI/NRC-RES Fire PRA Methodology for Nuclear Power Facilities Vol. 2 [4], and its Supplement 1 [5]. To confirm these methods, the NRC led an international experimental campaign from 2014 to 2016.

This experimental campaign is referred to as Phase 1 Testing. The results of these experiments

[2] uncovered a potential increase in hazard posed by aluminum components in or near electrical equipment, as well as unanalyzed equipment failure mechanisms.

In response to this new information, the NRC performed a thorough review of U.S. operating experience with a focus on instances where HEAF-like events have occurred in the presence of aluminum. This review uncovered six events where aluminum effects like those observed in the experiments were present. An Information Notice 2017-004, High Energy Arcing Faults in Electrical Equipment Containing Aluminum Components (IN 2017-04) detailing the relevant aspects of the licensee event reports and Phase 1 Testing was published in August of 2017 [2].

Additionally, RES staff proposed a potential safety concern as a generic issue (GI) in a letter dated May 6, 2016 [6]. The Generic Issue Review Panel (GIRP) completed its screening evaluation [7] for the proposed Generic Issue (GI) PRE-GI-018, HighEnergy Arc Faults 1

(HEAFs) Involving Aluminum, and concluded that the proposed issue met all seven screening criteria outlined in Management Directive (MD) 6.4, Generic Issues Program. Therefore, the GIRP recommended that this issue continue into the Assessment Stage of the GI program. The GIRP has completed an assessment plan, issued August 23, 2018 [8]. Though the HEAF research project will result in updated fire PRA guidance for all arcing faults, much of the HEAF research program exists to resolve PRE-GI-018 in accordance with the assessment plan.

These actions resulted in the identification of a need for more data to better understand the hazard. The NRC developed an experimental plan in collaboration with its international collaborative partners under the OECD/NEA program and based on information from a This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Phenomena Identification and Ranking Table (PIRT) exercise performed in 2017 [9].

1.2. Objectives The research objectives for this experimental series include: quantitatively characterize the thermal and pressure conditions created by HEAFs occurring in electrical enclosures and document the experiments and results.

1.3. Scope The scope of this research includes evaluating the HEAF hazard on low-voltage electrical equipment containing aluminum components. This characterization involves measurement and documentation of electrical and thermal parameters, along with physical evidence. Detailed data analysis for specific applications is beyond the scope of this report.

1.4. Approach The approach taken for this work follows practices from past efforts [2, 10]. Specifically, the test device (low-voltage switchgear) was faulted between the three phases. The testing laboratory provided electrical energy to the test device at the specified experimental parameters (system voltage, current, duration). Measurements internal and external to the gear were made using robust measurement devices fielded by the National Institute of Standards and Technology (NIST) and Sandia National Laboratories (SNL). Measurements were recorded, scaled, and reported. Feedback received during the developmental stage of this project was incorporated into the experimental approach. This included the arc locations, fault current magnitudes, and the durations of the experiments.

EXPERIMENTAL METHOD This section provides information on methods used to perform the experiments 1, including experimental planning, overview of the test facility, the test device, and the various instrumentation that were used.

1 The term test implies the use of a standardized test method promulgated by a standards development organization such as the International Organization for Standardization (ISO), ASTM International, Institute of Electrical and Electronics Engineers (IEEE), etc. The experiments described in this report are not standardized tests and were specifically developed to examine HEAF phenomena. The term test is used in some contexts to preserve continuity with previous programs or to describe facilities where standard tests are frequently performed. Standard test methods, where they exist, are used for some measurements.

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2.1. Experiment Planning The experimental plan was developed over an extended period with input provided by numerous stakeholders. Lessons learned from the Phase 1, results from the Phenomena Identification and Ranking Table (PIRT) exercise, and the literature were used to develop the initial experimental plan. The experimental plan is a living document and has undergone several revisions over time as new information is brought to light. Subsequent review and feedback by the OECD/NEA and other stakeholders resulted in changes to the plan. Support on this front from stakeholders and collaborative research partners such as the Electric Power Research Institute (EPRI) has greatly enhanced the experimental plan moving forward. The key central component of the experimental This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 plan is the experimental matrix which specifies the key parameters for each experiment. A graphical experimental matrix for electrical enclosures is presented in Fig. 1. The experiments shown in blue are sponsored jointly by the NRC and OECD/NEA member countries, while the experiments highlighted in orange are sponsored solely by the NRC to support the resolution of the Pre-GI. This report covers Test 2-13 and Test 2-18. The key parameters that are evaluated in this experimental campaign are arc duration and arcing current.

Enclosure Testing Copper Bus Bars Aluminum Bus Bars 480 Volt 6900 Volt 480 Volt 6900 Volt 13.5kA 25kA 25kA 32kA 13.5kA 25kA 25 kA 32 kA 2s 4s 8s 2s 4s 8s 2s 4s 4s 2s 4s 4s 2s 4s 8s 2s 4s 8s 2s 4s 4s 2s 4s 4s X X 2-1 2-2 2-3 2-4 2-5 2-6 2-7 2-8 2-9 2-10 2-11 2-12 2-13 2-14 2-15 2-16 2-17 2-18 2-19 2-20 2-21 2-22 2-23 2-24 *

• Fig. 1. Graphical Phase 2 Experimental Matrix for Electrical Enclosure 2.2. Experiment Facility The full-scale experiments were performed at KEMA Labs (referred to in the remainder of this report as KEMA), located in Chalfont, Pennsylvania. One round of experiments was performed in August of 2019. The test facility was chosen for its ability to meet the requirements of the program, specifically the electrical voltages, currents, and energies needed for sustained arcing within the subject enclosures and to permit fire conditions for a period after completion of the HEAF experiment. KEMA provided the electrical measurements required to quantify the characteristics of the power supplied to the enclosures during the arcing experiments. KEMA also provided radiant energy measurements.

The experimental test cell was composed of a cubical space with one open side. The open side was equipped with a roll-up door for security and weather protection when not in use. The open side of the test cell faces the operator control room, with a courtyard area between. The control room is equipped with impact resistant glazing so that the operators, clients, and guests can 3

observe the experiments. A door in the rear of the test cell leads to a protected space where NIST and SNL data acquisition equipment was located and operated.

Test Cell #7 was used during this experiment series to perform the low-voltage experiments. The test cell is shown in Fig. 2. Detailed drawings of the facility are provided in Appendix A.

Drawings of the test cell are courtesy of KEMA.

This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 4

This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Fig. 2. Isometric drawing of Test Cell #7 (left) and Location of Test Cell #7 with respect to KEMA facility (right).

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2.3. Test Device Two Westinghouse DS-type low-voltage indoor metal enclosed switchgear units were used in the experiments. Both switchgear were identical to each other, consisting of two vertical sections with four cubicles per vertical section. Each vertical section was 53 cm (21 in) wide, 233 cm (92 in) high, and an overall depth of 170 cm (67 in). The top cubicles in each section were configured as an auxiliary cubicle containing metering, switching, relaying, and protection circuitry. The other cubicles were configured as breaker cubicles. A supply cubicle housed a DS-416 supply breaker while other cubicles housed DS-206 breakers that were racked in, but not closed. The supply breaker was the only breaker closed during the experiment. The switchgear This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 was configured such that the laboratorys power supply was connected to the supply breaker run back, with the supply breaker closed and the main bus energized. The switchgear is shown in Fig. 3 through Fig. 5. The experiment test matrix is presented in Table 1.

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Fig. 3. Isometric drawing of low-voltage metal enclosed switchgear.

7 This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197

This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Fig. 4. Drawing of DS Switchgear as procured (all drawing dimensions in "centimeters")

Fig. 5. Photo of DS switchgear. (front (left); side and front (center); opposite side (right)).

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Table 1. Experimental Matrix Low-voltage DS Switchgear Experiments.

Test # Bus Material Voltage (V) Current (kA) Duration (s) 2-13 Aluminum 480 13.5 2 2-18 Aluminum 480 25.0 8 2.4. Instrumentation A variety of measurement equipment was used during the low-voltage DS switchgear experiments. Table 2 lists the measurement devices and the measurement that each device This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 provides. The instruments were arranged around the cell. A general configuration is shown in Fig. 6 followed by a photograph of the configuration in Fig. 7. A brief description of each device follows. Thermal, pressure, electromagnetic, conductivity, and electrical measurements were made using a variety of instruments and techniques. This section provides an overview of each, along with the methods and locations of measurement.

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Table 2. List of measurement equipment.

Measurements Instrument / Technique Temperature Infrared (IR) Imaging, Plate Thermometer (PT)

Electromagnetic Interference Free-field d-Dot Sensors Air Conductivity Planar conductivity sensors Air Breakdown Strength Breakdown Sensors This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Heat flux (time-varying) Plate Thermometer (PT)

Plate Thermometer (PT), Thermal Capacitance Slug Heat flux (average)

(Tcap slug), Radiometer ASTM F1959 Slug calorimeter (slug), Thermal Incident Energy Capacitance Slug (Tcap slug)

Arc plasma /

Videography, IR Imaging fire dimensions Sample collection (carbon tape), post-experiment Surface deposit analysis laboratory analysis (energy dispersive spectroscopy) high speed / high dynamic range imaging, cable Qualitative information samples 10

This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Fig. 6. Plan view of SNL instrumentation locations (note that locations are approximate, and instruments used varied by experiment. Illustration is not to scale). See details in Appendix A.2.

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This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Fig. 7. Photograph of instrumentation cluster (from Left-to-right, air breakdown, radiometer, d-dot, air conductivity, high speed IR and visible videography 2.4.1. Photometrics NIST and SNL fielded numerous imaging technologies during this experimental series to provide high-speed quantitative and qualitative imaging of the HEAF experiment evolution. The measurement methods included visible high-speed and high-definition imaging, high-speed high dynamic range visible imaging, and high-speed thermal imaging. The equipment fielded by NIST is like that used in the Phase 1 Testing [2] and experiments performed in 2018 [10] to capture high-definition visible and high-speed thermal images. Equipment fielded by SNL was a subset of equipment fielded in the 2018 experimental series [10]. The equipment selection was scaled down based on results and lessons learned. SNL reports document the approach, uncertainties, and results in greater detail [11].

The processed images can be accessed from the NRC RIL website 2:

https://www.nrc.gov/reading-rm/doc-collections/research-info-letters/index.html 2

The RIL website can be accessed by visiting http://www.NRC.gov, selecting the NRC Library >>

Document Collections >> Research Information Letters.

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2.4.2. High-Definition Videography High-definition (HD) video imaging was used to provide additional view angles for each experiment. Two types of camera were used. In the cell, action cameras were placed in protective housings and located on the floor or attached to the test cell wall. Their wide view angle and proximity provided a high resolution and detail of the early portion of the experiments. However, as the experiment progressed the effluent quickly obscured the view and detail these cameras could provide. The second set of HD cameras were located approximately 27 m from the front of the cell adjacent to thermal imaging cameras. The placement and zoom used on these cameras allowed for a macroscopic view of the entire cell or an area surrounding the box. These cameras This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 were 90-degrees orthogonal to the action camera placed on the test cell wall. One-half of these cameras were equipped with IR pass filters to better image the plasma / fire from the HEAF to allow improve image capture during arcing event.

2.4.3. Thermography Up to four thermal imaging cameras were used per experiment. Two of the cameras were supplied by NIST, while the other two were provided by SNL. The camera settings ranged in frame-rate, thermal calibration range, and resolution. The cameras were also placed in different locations. The NIST cameras were located outside the test cell approximately 26.5 m from and orthogonal to the KEMA cell roll up door opening. The SNL cameras were located outside of the cell and were housed within a mechanically ventilated metal enclosure. The thermal imagers used in this series are shown in Fig. 8, with courtyard locations shown in Fig. 9 and Fig. 10.

2.4.3.1. SNL The SNL thermal imagers were each housed in an enclosure that provided protection of the camera and networking components. An opening in the box allowed for the camera lenses to protrude out of the enclosure. The lenses were protected by locating the cameras at a distance and non-orthogonal axis to the HEAF effluent. Some of the cameras were configured such that the lens was not in direct exposure to the HEAF effluent. This was done by using a mirror and concrete barrier.

2.4.3.2. NIST The NIST thermal imaging was performed with two main goals. The first goal was to obtain qualitative information about the development and movement of the arc, the development of plumes of hot gases and HEAF products issuing from the open box, the impingement of the arc jets on the targets and thermal transducers, and the penetrations formed in the enclosure. The second goal was to provide quantitative measurements of box temperatures during and after the HEAF event. The thermal imaging measurements were performed by a FLIR model SC8243 imaging system and a Telops MS M350 imaging system.

The FLIR thermal imager is equipped with a 50 mm f/4.0 lens, with an InSb detector that has a nominal response range from 3 µm to 5 µm and a nominal pixel pitch of 18 µm by 18 µm. The imager can operate in full resolution mode of 1024 pixels by 1024 pixels at approximately 125 frames per second and can cover the temperature range of - 20 °C to 1500 °C (- 4 °F to 2732 °F) 13

using dynamic range extension techniques. For these experiments, to compliment the imaging performed by SNL imagers, the resolution was lowered to 319 pixels x 255 pixels, and the temperature range limited to 250 °C to 600 °C so that the frame rate could be increased to approximately 400 Hz.

The Telops thermal imager was equipped with a 50 mm f/2.3 lens, with a detector that has a nominal response range from 3.0 µm to 4.9 µm and a nominal pixel pitch of 16 µm by 16 µm.

The imager was operated in full resolution mode of 640 pixels by 512 pixels at approximately 350 frames per second. The video capture was performed using a spinning filter wheel with eight positions, filled with two consecutive series of four different transmittance neutral density filters.

This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 A dynamic range extension technique is applied, where the images from each series of four filters are captured, and post-processing software combines the images into one image with an expanded temperature range. After dynamic range extension is applied, the video images are 640 x 512 pixels in size, covering from - 0 °C to 2500 °C (- 4 °F to 4532 °F), with an effective video frame rate of approximately 88 Hz.

The uncertainty of the temperature results from the FLIR and Telops imagers are both specified by the manufacturer as +/- 2 °C or +/- 2 percent, with a 99 percent confidence interval. Using the NIST Uncertainty Machine [12], the expanded uncertainty in the temperature measurements of the metal surfaces is given in Table 3. Details of the uncertainty analysis can be found in a previous HEAF report [10].

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Table 3. Expanded uncertainty for IR imager temperatures Approximate Mean Temperature Uncertainty Coverage Surface Confidence Uncertainty Emissivity (°C) (°C) Factor Contribution Imager: 30%

Paint 0.94 100 +/- 2.6 95% 1.7 Emissivity: 70%

This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Imager: 70%

Paint 0.94 650 +/- 10.5 95% 1.9 Emissivity: 30%

Oxidized Imager: 20%

0.80 100 +/- 3.0 95% 1.8 Steel Emissivity: 80%

Oxidized Imager: 65%

0.80 650 +/- 11.1 95% 1.9 Steel Emissivity: 35%

Fig. 8. Thermal imagers (NIST thermal imaging cameras located approximately 26.5 m from test device (let), SNL imaging cameras located approximately 27 m from test device (right), from left to right (thermal, high speed visible, thermal))

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This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Fig. 9. Thermal imagers and high speed imagers are located in the courtyard. Four NIST cameras are in structure, approximately 26.5 m from the test device. Two SNL cameras are located outside the structure, approximately 27.0 m from the test device.

Fig. 10. Plan view of NIST and SNL camera locations (not to scale).

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2.4.4. Calorimetry Several types of calorimeters were used in these experiments. For all experiments, an SNL provided radiometer was used. This device was used in the previous small-scale experiments, and the results obtained during this experimental series provide direct comparisons. During the medium voltage box experiments, several thermal capacitance slug calorimeters and plate thermocouples were used. These devices were made available due to the cancellation of the planned medium voltage bus duct experiments. The types and configurations were selected based on the expected thermal exposure and ability of the device to survive.

This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 2.4.4.1. Plate Thermometer Modified plate thermometers (PTs) are robust thermal sensors that can survive in hostile HEAF environments [2, 10, 13]. They were chosen for heat flux measurements in the HEAF experiments due to their rugged construction, low cost, lack of cooling water, and known emissivity and convective heat transfer coefficients.

The modified plate thermometer used in the HEAF experiments is shown in Fig. 11. It consists of two 0.51 mm (0.02 in) nominal diameter (24 AWG) Type-K thermocouple wires welded directly to the rear of an 0.787 mm +/- 0.051 mm (0.031 in +/- 0.002 in, 99 percent confidence interval per manufacturer specifications) thick Inconel 600 plate, approximately 100 mm (3.94 in) by 100 mm (3.94 in) in size. The plate is backed by a mineral fiber blanket approximately 25.4 mm (1.0 in) thick to minimize heat loss. Machine screws with ceramic washers allow for legs to be attached at the rear of the plate thermometer to simplify installation onto instrumentation racks.

Fig. 11. Exploded view of modified plate thermometer (left); Cross-sectional view of modified plate thermometer placed on cone calorimeter sample holder (right).

The incident heat flux on a plate thermometer can be calculated from a heat balance using the following relation, a rearrangement of Equation 18 from Ingason and Wickstrom [14]:

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T (h + K )(T T ) PT CPT tPT q inc 4

= TPT +

PT cond PT

+ (1)

PT PT Here q inc is the incident heat flux, is the Stefan-Boltzmann Constant, 5.670x10-8 W/(m2*K4),

TPT is the temperature of the plate (K), hPT is the convection heat transfer coefficient, 10 W/(m2*K), Kcond is the conduction correction factor determined from NIST cone calorimeter data, 4 W/(m2*K), T is the ambient temperature (K), PT is the plate emissivity, 0.85 at 480 °C as rolled and oxidized and specified by the alloy manufacturer, PT is the alloy plate density, 8470 kg/m3 from the alloy manufacturer, CPT is the alloy plate heat capacity, 502 J/(kg*K) at 300 This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197

°C from the alloy manufacturer, is the alloy plate thickness, 0.79 mm (0.03 in), and t is the data acquisition time step of 0.1 s.

The gauge heat flux can also be calculated and is the heat flux listed in the tables of this report.

The gauge heat flux is the heat flux that would be reported by an ideal water-cooled transducer such as a Schmidt-Boelter or Gardon gauge operating at a constant temperature of Tgauge. The gauge heat flux, q gauge , is calculated from [14]:

T (h + K )(T T ) PT CPT tPT q gauge 4

= TPT +

PT cond PT

+ 4 Tgauge (2)

PT PT Type A evaluation of uncertainty is performed by the statistical analysis of a series of measurements. Type B evaluation of uncertainty is based on scientific judgement using relevant available information such as manufacturer specifications, calibration data, handbook data, previous experiments, and knowledge of the behaviors of materials and measurement equipment

[15, 16, 17].

The plate thermometer temperature increase, TPT , is reported along with the gauge heat flux.

The uncertainty in the temperature of the Type-K thermocouple wire is given by the manufacturer as +/-1.1 °C or 0.4 percent with a 99 percent confidence interval [18]. The expanded uncertainty in a PT temperature change of 0 °C to 1250 °C is 0.3 percent, with a coverage factor of 2, which corresponds to a confidence interval of 95 percent [15]. The expanded uncertainty in the heat flux measurement is +/- 1 kW/m2 or +/- 5 percent, with a coverage factor of 2, which corresponds to a confidence interval of 95 percent. Additional detail on the uncertainty determination can be found in the previous report [10].

2.4.4.2. ASTM Slug Calorimeters (Slug)

Incident energy was measured using slug calorimeters described in ASTM F1959 [20] and shown in Fig. 12. These instruments are customarily used to measure radiant energy and determine the arc flash hazard to personnel in the area of electrical enclosures. Due to the characteristics of the HEAF phenomena, which can result in convective arc jets, the calorimeters are reacting to convective heat transfer in addition to radiant heat transfer. ASTM slug calorimeters consist of a copper disc with an approximate thickness of 1.6 mm (0.063 in) and diameter of 40 mm (1.6 in). An iron-constantan thermocouple (Type J), composed of two 0.255 mm (0.01 in) nominal diameter (30 AWG) wires, is soldered to in the back of the copper disc 18

using silver solder. The ASTM standard specifies that the copper disc be installed in an insulation board. The KEMA slug calorimeters were installed in a G-11 fiberglass epoxy phenolic cup, which was then placed in a calcium silicate board holder nominally 100 mm by 100 mm by 32 mm thick (4 in by 4 in by 1.25 in nominal thickness) for mounting on instrument rack. The instruments were provided by KEMA. The slug temperatures were reported by the KEMA data acquisition system at a rate of 20 Hz.

The incident energy absorbed by the slug calorimeter during the HEAF experiments is calculated according to the methodology in ASTM F1959 [19]. The method reports the net heat absorbed over the arc duration and assumes that there are no losses from the disc due to re-radiation, This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 convection, or conduction to the disc holder. The absorptivity of the disc is assumed to be one.

The total energy per unit area, Q" , is calculated by:

m Cp (Tf Ti )

Q" = (3)

A where m is the mass of the copper disc, Cp is the average heat capacity of the copper disc, Tf is the temperature of the disc at the end of the arc, Ti is the temperature of the disc before the arc, and A is the front surface area of the disc. The total energy per unit area resulting from the arc is reported in a summary table for each sensor location in each experiment. The ASTM F1959 standard also refers to the total energy per unit area as incident energy (cal/cm2 or kJ/m2).

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32 Marinite Board 13 Thermocouple 40 102 Data Acquisition This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 51 56 Copper Disc G-11 Fiberglass Epoxy Cup Fig. 12. Cross-section of ASTM Slug (top) nominal dimensions in millimeters, photo of device being prepared in the field (bottom). Note that the two bolts on each side of the device are used for mounting to the DIN rail of the instrumentation rack.

The Type B standard uncertainty in the thermocouple measurement, derived from typical thermocouple manufacturer data, with a coverage factor of 2, is 2.2 °C or 0.75 percent. The ASTM calculation method assumes that the absorptivity of the disc is 1.0; however, inspection of 20

the discs over the course of the experiments suggests that the emissivity may vary from approximately 0.9 to 1.0, in a rectangular probability distribution. The expanded uncertainty in the incident energy measurement is +/- 18 kJ/m2 or +/- 4 percent, with a coverage factor of 2, which corresponds to a confidence interval of 95 percent. Additional detail on the uncertainty determination can be found in the previous report [10].

2.4.4.3.Thermal Capacitance Slugs (Tcap slug)

Tungsten thermal capacitance slugs (Tcap slug) were used to measure the heat flux and incident energy during the HEAF experiment. These sensors were developed as a result of experience This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 gained in Phase 1, where the thermal conditions during some experiments exceeded the measurement capabilities and caused destruction of the ASTM slug calorimeters and modified plate thermometers. A cross section of a Tcap slug is shown in Fig. 13, which is a modified example of the thermal capacitance slug described in ASTM E457-08 [21]. The slug is composed of a tungsten cylinder approximately 15 mm (0.59 in) long mounted in calcium silicate board. A type-K thermocouple is attached to the rear of the tungsten to measure the temperature during heating. The development of the Tcap is described in the previous report [10].

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32 Marinite Board Thermocouple 102 15.0 Data Acquisition 25.4 This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Tungsten Cylinder Fig. 13. Thermal capacitance style slug, illustration (top left), photo of device being prepared in the field (top right), dimensional drawings showing internal construction (bottom left and right). All dimensions in mm.

The maximum heat flux was determined from Equation (4), where (" ) is the heat flux into the surface of the tungsten slug (kW/m2), is the density of the tungsten slug (kg/m3), ( ) is the average heat capacity of the tungsten slug (kJ/[kg K]), l is the thickness (m), T is the change in temperature of the tungsten slug (°C), and t is the corresponding change in time (s).

" = (4)

An uncertainty analysis using Type A and Type B components was performed on the Tcap slug at 50 kW/m2 and 5 MW/m2 using the NIST Uncertainty Machine [12] with cone calorimeter data and fire dynamics simulator (FDS) [19] simulations. The expanded uncertainty in the heat flux 22

measurement is +/- 1.5 kW/m2 or +/- 2.9 percent, with a coverage factor of 2, which corresponds to a confidence interval of 95 percent.

The expanded uncertainty of the incident energy over the measurement range is estimated at +/-

2.4 kJ/m2 or +/- 5 percent, with a 95 percent confidence interval, which includes the estimated error due to conduction effects. Additional details on the development of the Tcap heat transfer analysis, and uncertainty determinations can be found in the previous report [10].

2.4.4.4.Data Acquisition System This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 The NIST data acquisition system used a combination of shielding, grounding, isolation, and system configuration that reduced the impact of electromagnetic interference (EMI), as shown in Fig. 14. This data acquisition system was used for the plate thermometer and Tcap instruments and is described in the literature [2, 10, 13]. A TTL signal with a known delay time was used to synchronize to the KEMA data acquisition and control system.

Fig. 14. Data Acquisition System Configuration with EMI rejection.

2.4.5. Pressure Transducer Pressure measurement methods were improved from the Phase 1 experiments. First, the test laboratory changed the data link cable between the data acquisition cart (located in the test cell) and the data logging station (located in the control room) to a fiber optic cable. This greatly improved the signal to noise ratio and resistance to EMI. Secondly, a magnetic shielding alloy (Mu-metal) was used to shield the sensor. This material is a ferromagnetic alloy with a very high 23

magnetic permeability. The material was installed around the pressure sensor between the sensor and the PVC enclosure. Lastly, piezoelectric-style pressure transducers were used instead of the strain gauge-type in Phase 1. The combination of these three changes greatly improved the electromagnetic interference (EMI) rejection.

The assembly for measuring pressure consisted of a through-bolt that was installed in a hole drilled in the metal cladding of the electrical switchgear enclosure. A 90-degree fitting was connected to the through-bolt on one end, and a pressure hose was connected to the other. The opposite end of the pressure hose was connected to the pressure transducer, which was housed within a white PVC tube for mechanical protection. Within the PVC tube, the Mu-metal was This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 installed. The electrical connection from the transducer exited the PVC tube and was routed to the data collection cart. Prior to the experiments, additional thermal protection was added to the electrical cable by surrounding it with ceramic fiber thermal insulation and secured with fiberglass tape. The configuration is shown in Fig. 15 and Fig. 16. Two general locations were selected. At each location, transducers of different nominal ranges were used. One ranged from 0 kPa (0 psia) to 207 kPa (30 psia), while the other ranged from 0 kPa (0 psia) to 345 kPa (50 psia). Pressure transducers labeled PT3 and PT4 measured the primary cable connection compartment pressure where the arc was initiated, while transducers PT1 and PT2 measured pressure in the breaker cubicle.

Fig. 15. Photos of pressure measurement locations (PT3 and PT4 (left); PT1 and PT2 (right)).

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PRESSURE PRESSURE TRANSDUCER TRANSDUCER This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Fig. 16. Drawings showing locations of pressure sensor devices.

2.4.6. Auxiliary Measurements Several instruments were fielded to characterize the electromagnetic interference, air conductivity, and voltage holdoff strength. These devices are discussed in detail in the previous report [23]. The lack of switchgear enclosure breach or location of breach relative to the instruments resulted in the measured data of no value. As such, these measurements are not reported.

2.4.7. Mass Loss Measurements Mass loss measurements of electrode and enclosure material were not made. This is due to the large mass of the switchgear main bus, difficulty in separating the main bus from the switchgear, and the uncertainty of the measurement.

2.4.8. Electrical Data Acquisition and Processing Electrical measurements were made by the KEMA Labs. The measurements included line-to-ground voltages at the generator and just prior to the test device in the test cell and current measurements downstream of the test device (not in the test cell) but downstream of any transformer. The reported voltages in this report are the voltage at the test device and are line-to_ground voltages (unless stated otherwise). The uncertainties in the measurements made by KEMA Labs were +/- 3 percent.

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2.4.9. Cable Samples Cable samples (coupons) were provided in every experiment as a passive indication of thermal damage. The inclusion of cable samples was highly recommended by stakeholders during the April 2018 public workshop [24].

The cable coupons were constructed using six or eight segments of cable, approximately 100 mm (4 in) long. The cables were affixed to a square piece of fiberglass reinforced cement board (Durock'), measuring approximately 100 mm (4 in) square and nominally 13 mm (0.5 in)

This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 thick, using steel wire protected with a glass braid sheath. The wire was also used to connect the cable coupon to the horizontal steel DIN rail. Descriptions and specifications of the cables are listed in Table 4 and Table 5. Face and side views of a typical cable coupon are presented in Fig. 17 and Fig. 18.

Table 4. Manufacturers' descriptions of the cables used in the experiments.

Cable Source Manufacturer Date Cable Markings No.

900 Purchased Lake Cable

1. 2582 FT. TPT127 LAKE CABLE 12AWG 7C 2015 PE/PVC2010 CONTROL CABLE 600V 75 C 2015 ROHS 11 REACH MADE IN USA 280547 Note that the CAROLFIRE # refers to the number assigned to that particular cable during the CAROLFIRE program [25]

Table 5. Nominal cable properties.

Jacket Thickness (mm) Mass per Length (kg/m) Copper Mass Fraction Jacket Mass Fraction Filler Mass Fraction Insulator Thickness Insulation Material Insulation Mass Jacket Material Conductors Diameter (mm)

Cable No. Class.

Fraction (mm) 900 PE PVC TP 7 15.9 1.85 1.07 0.38 0.55 0.27 0.10 0.08 26

This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Fig. 17. Cable coupon constructed of seven conductor PE / PVC control cable (Cable 900). Front view.

Fig. 18. Cable coupon constructed of seven conductor PE / PVC control cable (Cable 900).

Side view.

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2.4.10. Instrument Deployment The majority of the thermal instrumentation devices were located on instrument racks with the faces of the instruments located approximately 0.91 m (3.00 ft) from the exterior sides of the metal clad enclosure. Two instrument racks were also located horizontally above the electrical enclosure (Rack 4 and Rack 5), supported by a reconfigurable steel structure. The sensors on Rack 4 were located approximately 0.91 m (3.00 ft) from the top of the enclosure, while the sensors on Rack 5 were located approximately 1.83 m (6.00 ft) from the top of the enclosure.

The location of the upper horizontal rack was horizontally offset by approximately 102 mm (4.0 in) from the lower rack to reduce shadowing from the sensors below. The instrumentation rack This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 configuration for Test 2-13A through Test 2-13G is shown in Fig. 19 and Fig. 20. The instrument rack configuration for Test 2-18A and Test 2-13B is shown in Fig. 21 and Fig. 22. Details of the instrument locations are shown in Fig. 23 through Fig. 29, with a photograph showing the instrumentation racks around the test devices during setup in Fig. 30 and Fig. 31. The expanded uncertainty in the measurement of the distances from the instrumentation racks to the electrical enclosure is +/- 13 mm (0.5 in) with a coverage factor of 2 and an estimated confidence interval of 95 percent.

Fig. 19. Elevation view of instrument rack configuration around electrical enclosure for Test 2 13A through 2 13G. Dimensions in mm.

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This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Fig. 20. Plan view of instrument rack configuration around electrical enclosure for Test 2-13A through 2-13G. Dimensions in mm. The switchgear enclosure is approximately 1.080 m (42.5 in) wide, 1.708 m (67.3 in) deep, and 2.337 m (92.0 in) tall.

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This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Fig. 21. Elevation view of instrument rack configuration around electrical enclosure for Test 2-18A and 2-18B. Dimensions in mm.

30

This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Fig. 22. Plan view of instrument rack configuration around electrical enclosure for Test 2 18A and 2-18B. The enclosure is approximately 1.080 m (42.5 in) wide, 1.708 m (67.3 in) deep, and 2.337 m (92.0 in) tall.

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This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Fig. 23. Illustration of Vertical Instrumentation Rack 1 with data acquisition channels . Dimensions in mm +/- 5 mm.

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This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Fig. 24. Detailed Horizontal Locations of Instruments on Instrument Racks 1, 2, 3, 4, 5, and 6.

Dimensions in mm +/- 5 mm.

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This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Fig. 25. Illustration of Vertical Instrumentation Rack 2 with data acquisition channels. Dimensions in mm +/- 5 mm.

34

This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Fig. 26. Illustration of Vertical Instrumentation Rack 3 with data acquisition channels. Dimensions in mm +/- 5 mm.

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This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Fig. 27. Illustration of Horizontal Instrumentation Rack 4 with data acquisition channels. Dimensions in mm +/- 5 mm. Rack was installed so that the sensors are located approximately 0.91 m (3.00 ft) from the top of the enclosure metal cladding.

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This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Fig. 28. Illustration of Horizontal Instrumentation Rack 5 with data acquisition channels. Dimensions in mm +/- 5 mm. Rack was installed so that the sensors are located approximately 1.83 m (6.00 ft) from the top of the enclosure metal cladding.

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This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Fig. 29. Illustration of Vertical Instrumentation Rack 6 with data acquisition channels. Dimensions are the same as Instrument Racks 1, 2, 3, 4, and 5. Note that this rack was rotated clockwise 90 degrees as shown on left bottom.

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Fig. 30. Photo of Instrumentation Racks for Test 2-13A through Test 2-13G.

39 This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197

Fig. 31. Photo of Instrumentation Racks for Test 2-18A Test 2-18B.

40 This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197

Experimental Results The KEMA Labs performed calibration runs to ensure that the power circuits selected met the desired experimental parameters. The calibrations are measured at a shorting bus within the laboratorys facility, and the actual experimental conditions will be slightly different because of the additional circuit length to the test device and that of the test device. The resulting calibration tests are presented in Table 6, with detail provided in the KEMA report (Appendix C).

Table 6. Circuit Calibration. Measurements are +/- 3 percent.

This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Voltage (V) Current Sym (kA) Current Peak (kA) Circuit 616 13.5 35.6 190826-7001 489 13.5 35.5 190826-7002 619 24.2 52.7 190829-7001 619 25.1 51.0 190829-7002 480 25.7 55.4 190829-7003 480 25.3 34.0 190829-7004 The calibration tests were performed for about 10 cycles to ensure stabilization of the waveform. The duration of the arc during an actual experiment was controlled by the ability to maintain the arc within the enclosure and the breaking of the circuit by the test laboratorys protective device(s). Provided that the arc did not prematurely extinguish prior to the desired arc time, the testing laboratory ensured that the arc duration parameter was met by automatically triggering their protectives devices to open at the specified duration.

Because there was a delay in the opening of the circuit (breaker opening time), the actual durations were longer than the desired durations. Table 7 presents the experimental parameter variations performed for these series of experiments.

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Table 7. Summary of LV switchgear experiments Voltage (V) Current (A) Duration (s) Notes Location System Actual Planned Actual Planned Actual Test Arc No.

Main bus, top Arc 2-13A 480 489 388 13 500 9 800 2.000 0.950 vertical buses, terminated This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 load section prematurely Main bus, top Arc 2-13B 600 617 421 13 500 9 973 2.000 0.399 vertical buses, terminated load section prematurely Main bus, top Arc 2-13C 600 617 298 13 500 11 650 2.000 0.413 vertical buses, terminated load section prematurely Main bus, top Arc 2-13D 600 617 426 13 500 9 266 2.000 0.926 vertical buses, terminated load section prematurely Breaker cubicle, 2-13E 600 616 305 13 500 10 388 2.000 2.060 middle cube, load section Main bus, Arc bottom vertical 2-13F 480 488 302 13 500 9 733 2.000 1.550 terminated buses, load prematurely section Main bus, bottom vertical 2-13G 600 616 330 13 500 10 707 2.000 2.020 buses, supply section Main bus, Arc bottom vertical 2-18A 480 427 336 25 000 19 146 8.000 2.020 terminated buses, load prematurely section Main bus, bottom vertical 2-18B 600 602 415 25 000 19 349 8.000 8.310 buses, supply section 42

3.1. Test 2-13A - 480 V, 13.5 kA, 2 s duration, main bus top load section Test 2-13A was performed on August 26, 2019 at 4:55 PM eastern daylight time (EDT). The temperature was approximately 23 °C (73 °F), approximately 51 percent relative humidity and approximately 101.7 kPa of pressure. The weather was mostly cloudy with a 14 km/h (9 mi/h) wind out of the east.

The arc was located near the top of the main bus bar in the load section of the switchgear. The arcing wire installed on the bus and marked up illustrations of the arc wire location is presented in Fig. 32.

This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Fig. 32. Shorting wire location Test 2-13A (Phases left-to-right: A-B-C), photo of arc initiation point (left), elevation view (center), plan view (right). Shorting location shown in red on illustrations.

3.1.1. Observations Observations documented below are based on review of video and thermal imaging that was taken during the experiment. The observations are provided in Table 8 and include an approximate time reference. Corresponding images are provided in Fig. 33.

The experiment did not arc for the planned 2.0 s. Arcing on all three phases was intermittent for the first 500 ms with a 368 ms phase of no arcing and a brief 62 ms of arcing occurring on phase B and C only. The arcing wire successfully initiated the arc, and the arc moved towards the top of the bars as predicted but it likely extinguished at the top of the bars. There was minimal degradation to the bars themselves and minimal impact on the enclosure and instrument stands.

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Table 8. Observations from Test 2-13A Time (ms) Observation 0 Initial light observed in top rear louver 50 Particle ejecta observed 150 Particle ejecta reaches first instrument rack immediately above enclosure Luminescent flash zone reaches first instrument rack immediately above 250 enclosure 450 Particle ejecta reaches second instrument rack above enclosure This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Particle ejecta stream observed on left side of load vertical section extending 600 vertically upward to top instrumentation rack 900 Arc re-strikes 950 Last particle ejecta prior to final arc extinguishment 391 600 NIST data acquisition ends 44

Fig. 33. Sequence of Images from Test 2-13A (image time stamps are in seconds).

45 This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197

Photograph of the enclosure following the experiment is presented in Fig. 34. The enclosure did not experience a breach.

This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Fig. 34. Enclosure Post-Test 2-13A.

3.1.1.1.Measurements Measurements made during Test 2-13A are presented below. These measurements include:

• Thermal o Heat flux - Plate Thermometers o Heat flux, incident energy - Tcap Slug Calorimeter

• Pressure o Internal pressure

• Electrical o Voltage profiles o Current profiles o Power and energy profiles 46

3.1.1.2.Thermal Measurements Thermal measurements from the active instruments are reported below. These include PT measurements (Table 9) and Tcap slug measurements (Table 10). The maximum reading is identified with bold text. ASTM Slug Calorimeter measurements are not reported as the data capture did not include pre-test measurements to allow for the calculation of incident energy. This was resolved for future experiments.

Due to the short duration of the arc and no breaching of the exterior skin of the switchgear, the thermal exposures measured outside of the switchgear were very small.

This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Table 9. Summary of plate thermometer measurements Test 2-13A Average Heat Flux During Max Heat Flux (kW/m2)

Rack Plate Arc (kW/m2)

Location +/- 1 kW/m2 No. No. +/- 1 kW/m2 or +/- 5 %

or +/- 5 %

1 1 Top 4 1 1 3 Mid-Right 1 0 1 5 Mid-Center 1 0 1 7 Mid-Left 1 0 1 9 Bottom 0 0 2 10 Top 1 0 2 12 Mid-Right 0 0 2 14 Mid-Center 0 0 2 16 Mid-Left 0 0 2 18 Bottom 2 0 3 19 Top 4 1 3 21 Mid-Right 14 0 3 23 Mid-Center 2 0 3 25 Mid-Left 1 0 3 27 Bottom 1 0 4 28 Front 5 1 4 30 Center-Right 24 4 4 32 Center-Mid 7 3 4 34 Center-Left 4 1 4 36 Back 10. 3 47

Average Heat Flux During Max Heat Flux (kW/m2)

Rack Plate Arc (kW/m2)

Location +/- 1 kW/m2 No. No. +/- 1 kW/m2 or +/- 5 %

or +/- 5 %

5 37 Front 1 1 5 39 Center-Right 4 2 5 41 Center-Mid 3 1 5 43 Center-Left 2 1 This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 5 45 Back 3 1 Table 10. Summary of Tcap slug measurements, Test 2-13A.

Heat Flux During Incident Energy During Total Incident Rack Tcap Arc (kW/m2) Arc Phase (kJ/m2) Energy (kJ/m2)

Location No. No. 1.5 kW/m2 +/- 2.4 kJ/m2 +/- 2.4 kJ/m2 or +/- 2.9 % or +/- 5 % or +/- 5 %

1 2 Top 0.2 0.2 1.2 1 4 Mid-Right 0.1 0.0 0.5 1 6 Mid-Left 0.1 0.1 0.6 1 8 Bottom 0.0 0.0 0.4 2 11 Top 0.2 0.0 0.3 2 13 Mid-Right 0.0 0.0 0.1 2 15 Mid-Left 0.2 0.1 0.4 2 17 Bottom 0.0 0.0 0.3 3 20 Top 0.3 0.3 13.0 3 22 Mid-Right 0.2 0.2 11.1 3 24 Mid-Left 0.8 0.2 10.7 3 26 Bottom 0.2 0.0 10.3 4 29 Front 1.6 1.7 14.2 4 31 Center-Right 3.3 2.7 21.3 4 33 Center-Left 1.6 1.8 14.3 4 35 Back 2.7 2.8 17.9 5 38 Front 1.0 0.7 5.1 5 40 Center-Right 1.3 1.1 7.3 5 42 Center-Left 0.9 0.7 4.4 5 44 Back 0.6 0.6 5.1 48

3.1.1.3. Pressure Measurements The pressure profiles for the first two tenths of a second are shown in Fig. 35. After the initial pressure spike, the pressure rapidly decays to a relative steady state. The peak pressure is higher in the main bus compartment as would be expected since this is the compartment where the arc is initiated. The maximum change in pressure in the primary cable connection compartment is approximately 10 kPa (1.5 psi) above ambient at its peak. The maximum change in pressure in the breaker compartment is approximately 4 kPa (0.6 psi) above ambient. The 0 kPa to 207 kPa (0 psia to 30 psia) and 0 kPa to 345 kPa (0 psia to 50 psia) transducer recordings at a specific location were consistent.

This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Fig. 35. Pressure measurements from Test 2-13A (breaker compartment (left); Main bus [arcing compartment] - (right)). Measurement uncertainty +/- 3 percent.

3.1.1.4. Electrical measurements Test 2-13A used KEMA circuit S06 and is reported in Appendix C. Full-level circuit checks (calibration tests) were performed prior to the experiment to verify the experimental parameters were acceptable. For this experiment the calibration tests configured the power system to 0.489 kV, 13.5 kA symmetrical, and 35.5 kA peak. The KEMA report (Appendix C) identifies this experiment as 190826-7003. Key experimental measurements are presented in Table 11. Plots of the electrical measurements are presented in Appendix B.

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Table 11. Key measurement from Test 2-13A. Measurement uncertainty +/- 3 percent.

Phase Units A B C Applied voltage, phase-to-ground kVRMS 282 282 282 Applied voltage, phase-to-phase kVRMS 488 Making current kApeak 24.0 23.8 -28.7 Current, a.c. component, beginning kARMS 10.7 11.9 10.2 Current, a.c. component, middle kARMS 7.52 9.15 5.89 Current, a.c. component, end kARMS 7.98 4.04 5.44 Current, a.c. component, average kARMS 8.78 9.35 7.71 This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Current, a.c. component, three-phase average kARMS 8.61 Duration s 0.519 0.519 0.519 Arc Energy MJ 1.65 3.2. Test 2-13B - 600 V, 13.5 kA, 2 s duration, main bus top load section Test 2-13B was performed on August 27, 2019 at 9:01 AM eastern daylight time (EDT). The temperature was approximately 20 °C (68 °F), approximately 73 percent relative humidity and approximately 101.6 kPa of pressure. The weather was cloudy with a 11 km/h (7 mi/h) wind out of the northeast.

The switchgear used in Test 2-13A was used again in this experiment. The gear was tested for sufficient insulation resistance between phases and found to be functional. The arc was located near the top of the main bus bar in the load section of the switchgear. Two 10 AWG bare stranded conductors were used to initiate the arc. The arcing wire installed on the bus and marked up illustrations of the arc wire location is presented in Fig. 36.

Fig. 36. Shorting wire location Test 2-13B (Phases left-to-right: A-B-C), photo of arc initiation point (left), elevation view (center), Plan View (right). Shorting location shown in red on illustrations.

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3.2.1. Observations Observations documented below are based on review of video and thermal imaging that was taken during the experiment. The observations are provided in Table 12 and include an approximate time reference. Corresponding images are provided in Fig. 37.

The experiment did not arc for the planned 2.0 s. Arcing on all three phases was intermittent for the first 400 ms. The arcing wire successfully initiated the arc, and the arc moved towards the top of the bars as predicted but it likely extinguished at the top of the bars. There was minimal degradation to the bars themselves and minimal impact on the enclosure and instrument stands.

This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Table 12. Observations from Test 2-13B Time (ms) Observation 0 Initial light observed in top rear louver 66 Particle ejecta reaches first instrument rack immediately above enclosure 150 Particle ejecta reaches second instrument rack above enclosure Luminescent flash zone reaches first instrument rack immediately above 200 enclosure Particle ejecta continue to be vertically oriented and localized to left side of 250 load vertical section 333 Particle ejecta stream observed on left and right side of switchgear.

400 Luminescent intensity diminishing 450 Last particle ejecta at arc extinguishment 358 000 NIST data acquisition ends 51

This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Fig. 37. Sequence of Images from Test 2-13B (image time stamps are in seconds).

Photograph of the enclosure following the experiment is presented in Fig. 38. The enclosure did not experience a breach.

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This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Fig. 38. Enclosure Post-Test 2-13B.

3.2.1.1.Measurements Measurements made during Test 2-13B are presented below. These measurements include:

• Thermal o Heat flux - Plate Thermometers o Incident energy - ASTM Slug Calorimeter o Heat flux, incident energy - Tcap Slug Calorimeter

• Pressure o Internal pressure

• Electrical o Voltage profiles o Current profiles o Power and energy profiles 53

3.2.1.2.Thermal Measurements Thermal measurements from the active instruments are reported below. These include PT measurements (Table 13), ASTM Slug Calorimeter measurements (Table 14), and Tcap slug measurements (Table 15). The maximum reading is identified with bold text. For some measurements, the EMI magnitude was of the same order as the signal. These are listed as --

and noted with EMI S/N.

Due to the short duration of the arc and no breaching of the exterior skin of the switchgear, the This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 thermal exposures measured outside of the switchgear were very small.

Table 13. Summary of plate thermometer measurements Test 2-13B.

Max Heat Flux Average Heat Flux Rack Plate Location (kW/m2) During Arc (kW/m2) Comment No. No.

+/- 1 kW/m2 or +/- 5 % +/-1 kW/m2 or +/- 5 %

1 1 Top 2 0 1 3 Mid-Right 9 0 1 5 Mid-Center 0 0 1 7 Mid-Left 0 0 1 9 Bottom 0 0 2 10 Top 0 0 2 12 Mid-Right 0 0 2 14 Mid-Center 0 0 2 16 Mid-Left 0 0 2 18 Bottom 0 0 3 19 Top 5 0 3 21 Mid-Right 0 EMI S/N 3 23 Mid-Center 3 0 3 25 Mid-Left 1 0 3 27 Bottom 1 0 4 28 Front 4 1 4 30 Center- 6 2 Right 4 32 Center-Mid 15 3 54

Max Heat Flux Average Heat Flux Rack Plate Location (kW/m2) During Arc (kW/m2) Comment No. No.

+/- 1 kW/m2 or +/- 5 % +/-1 kW/m2 or +/- 5 %

4 34 Center-Left 6 1 4 36 Back 9 2 5 37 Front 1 1 5 39 Center- 2 1 Right 5 41 Center-Mid 2 1 This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 5 43 Center-Left 2 1 5 45 Back 3 1 Table 14. Summary of ASTM slug calorimeter measurements, Test 2-13B.

Incident Energy Time to Max Rack ASTM No. Location (kJ/m2) Temperature (s) +/-

No.

+/- 18kJ/m2 or +/- 4 % 3%

1 A Top 1 0.6 1 B Bottom 1 12.6 2 C Top 1 5.6 2 D Bottom 1 5.6 3 E Top 1 17.8 3 F Bottom 1 17.8 4 G Rear 6 15.5 4 H Front 6 18.6 5 I Rear 4 18.7 5 J Front 2 5.2 Table 15. Summary of Tcap slug measurement, Test 2-13B.

Heat Flux Incident Energy Total Incident During Arc During Arc Phase Rack Tcap Energy (kJ/m2)

Location (kW/m2) (kJ/m2)

No. No. +/- 2.4 kJ/m2

+/- 1.5 kW/m2 +/- 2.4 kJ/m2 or +/- 5 %

or +/- 2.9 % or +/- 5 %

1 2 Top 0.2 0.2 3.6 1 4 Mid-Right 0.1 0.3 2.1 1 6 Mid-Left 0.0 0.0 1.8 1 8 Bottom 0.1 0.1 1.0 2 11 Top 0.2 0.0 0.0 2 13 Mid-Right 0.1 0.0 0.2 55

Heat Flux Incident Energy Total Incident During Arc During Arc Phase Rack Tcap Energy (kJ/m2)

Location (kW/m2) (kJ/m2)

No. No. +/- 2.4 kJ/m2

+/- 1.5 kW/m2 +/- 2.4 kJ/m2 or +/- 5 %

or +/- 2.9 % or +/- 5 %

2 15 Mid-Left 0.1 0.0 0.1 2 17 Bottom 0.2 0.1 0.2 3 20 Top 0.3 0.5 12.7 3 22 Mid-Right 0.3 0.4 11.4 This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 3 24 Mid-Left 0.3 0.5 12.3 3 26 Bottom 0.1 0.2 8.3 4 29 Front 1.6 3.4 15.7 4 31 Center-Right 1.7 4.2 19.9 4 33 Center-Left 2.1 4.2 15.4 4 35 Back 1.8 4.4 19.4 5 38 Front 0.9 1.3 4.6 5 40 Center-Right 0.7 1.1 4.7 5 42 Center-Left 0.7 1.0 3.4 5 44 Back 0.7 1.1 3.7 3.2.1.3. Pressure Measurements The pressure profiles for the first two tenths of a second are shown in Fig. 39. After the initial pressure spike, the pressure rapidly decays to a relative steady state. The peak pressure is higher in the primary cable connection compartment as would be expected since this is the compartment where the arc is initiated. The maximum change in pressure in the main bus compartment is approximately 5 kPa (0.7 psi) above ambient at its peak. The maximum change in pressure in the breaker compartment is approximately 3 kPa (0.4 psi) above ambient. The 0 kPa to 207 kPa (0 psia to 30 psia) and 0 kPa to 345 kPa (0 psia to 50 psia) transducer recordings at a specific location were consistent.

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This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Fig. 39. Pressure measurements from Test 2-13B (breaker compartment (left); Main bus [arcing compartment] (right). Measurement uncertainty +/- 3 percent.

3.2.1.4.Electrical measurements Test 2-13B used KEMA circuit S07 and is reported in Appendix C. Full-level circuit checks (calibration tests) were performed prior to the experiment to verify the experimental parameters were acceptable. For this experiment the calibration tests configured the power system to 0.616 kV, 13.5 kA symmetrical, and 35.6 kA peak. The KEMA report identifies this experiment as 190827-7001. Key experimental measurements are presented in Table 16. Plots of the electrical measurements are presented in Appendix B.

Table 16. Key measurement from Test 2-13B. Measurement uncertainty +/- 3 percent.

Phase Units A B C Applied voltage, phase-to-ground kVRMS 356 356 356 Applied voltage, phase-to-phase kVRMS 617 Making current kApeak 24.7 28.5 -34.3 Current, a.c. component, beginning kARMS 13.4 14.0 2.05 Current, a.c. component, middle kARMS 8.76 7.33 6.74 Current, a.c. component, end kARMS 0.00 0.00 7.95 Current, a.c. component, average kARMS 9.91 9.46 8.27 Current, a.c. component, three-phase average kARMS 9.22 Duration s 0.332 0.332 0.396 Arc Energy MJ 1.38 57

3.3. Test 2-13C - 600 V, 13.5 kA, 2 s duration, main bus top load section Test 2-13C was performed on August 27, 2019 at 10:19 AM eastern daylight time (EDT). The temperature was approximately 21 °C (70 °F), approximately 68 percent relative humidity and approximately 101.9 kPa of pressure. The weather was cloudy with a 11.3 km/h (7 mi/h) wind out of the east.

The switchgear used in Tests 2-13A and 2-13B was used again in this experiment. The gear was tested for sufficient insulation resistance between phases and found to be functional. The arc was located near the top of the main bus bar in the load section of the switchgear. A single 10 AWG This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 bare stranded conductors were used to initiate the arc. Due to the previous two experiments not maintaining the arc for the planned arc duration, a shorting plate was added near the top of the vertical main bus bars to allow for arc attachment and reduce the likelihood self-extinguishment.

The grounding place was approximately 18 cm (7 in) above the top of the vertical main bus bars.

This distance was selected based on available attachment points within the switchgear and discussion with the NRC/RES - EPRI HEAF working group and their review of applicable drawings. The arcing wire installed on the bus, ground plate, and marked up illustrations of the arc wire location is presented in Fig. 40.

Fig. 40. Shorting Wire Location Test 2-13C (Phases left-to-right: A-B-C) (top left); grounding plate (top right); illustration of shorting wire (red) and grounding plate (blue) locations (bottom left) elevation view and plan view (bottom right).

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3.3.1. Observations Observations documented below are based on review of video and thermal imaging that was taken during the experiment. The observations are provided in Table 17 and include an approximate time reference. Corresponding images are provided in Fig. 41.

The experiment did not arc for the planned 2.0 s. Arcing on all three phases was less intermittent than previous experiments but still extinguished at approximately 413 ms. The arcing wire successfully initiated the arc, and the arc moved towards the top of the bars as predicted. There is no apparent evidence of arc damage to the ground plate due to arc root attachment; however, there This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 is some metal splatter and mild soot covering the plate. It is likely that the gap was too large to support arc attachment and sustained ignition. There was minimal degradation to the bars themselves and minimal impact on the enclosure and instrument stands.

Table 17. Observations from Test 2-13C.

Time (ms) Observation 0 Initial light observed in top rear louver 66 Initial particle ejecta observed 100 Particle ejecta reaches first instrument rack immediately above enclosure Luminescent flash zone reaches first instrument rack immediately above 150 enclosure 250 Luminescent flash zone expands horizontally 350 Particle ejecta reaches second instrument rack above enclosure 400 Luminescent flash zone intensity diminishing 450 Last particle ejecta at arc extinguishment 686 500 NIST data acquisition ends 59

Fig. 41. Sequence of Images from Test 2-13C (image time stamps are in seconds).

60 This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197

Photographs of the enclosure following the experiment is presented in Fig. 42. The enclosure did not experience a breach.

This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Fig. 42. Enclosure Post-Test 2-13C. Top photo showing top of vertical main buses. Bottom photo.

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3.3.1.1. Measurements Measurements made during Test 2-13C are presented below. These measurements include:

• Thermal o Heat flux - Plate Thermometers o Incident energy - ASTM Slug Calorimeter o Heat flux, incident energy - Tcap Slug Calorimeter

• Pressure This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 o Internal pressure

• Electrical 3.3.1.2. Thermal Measurements Thermal measurements from the active instruments are reported below. These include PT measurements (Table 18), ASTM Slug Calorimeter measurements (Table 19), and Tcap slug measurements (Table 20). The maximum reading is identified with bold text. For some measurements, the EMI magnitude was of the same order as the signal. These are listed as --

and noted with EMI S/N.

Due to the short duration of the arc and no breaching of the exterior skin of the switchgear, the thermal exposures measured outside of the switchgear were very small.

Table 18. Summary of plate thermometer measurements Test 2-13C.

Max Heat Flux Average Heat Flux Rack Plate Location (kW/m2) During Arc (kW/m2) Comment No. No.

+/- 1 kW/m2 or +/- 5 % +/- 1 kW/m2 or +/- 5 %

1 1 Top 3 0 1 3 Mid-Right 0 0 1 5 Mid-Center 7 0 1 7 Mid-Left 1 0 1 9 Bottom 1 0 2 10 Top 0 0 2 12 Mid-Right 0 0 62

Max Heat Flux Average Heat Flux Rack Plate Location (kW/m2) During Arc (kW/m2) Comment No. No.

+/- 1 kW/m2 or +/- 5 % +/- 1 kW/m2 or +/- 5 %

2 14 Mid-Center 0 0 2 16 Mid-Left 0 0 2 18 Bottom 0 0 This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 3 19 Top 3 0 3 21 Mid-Right 0 EMI S/N 3 23 Mid-Center 2 0 3 25 Mid-Left 1 0 3 27 Bottom 0 0 4 28 Front 3 0 4 30 Center- 5 2 Right 4 32 Center-Mid 13 3 4 34 Center-Left 7 1 4 36 Back 9 2 5 37 Front 1 0 5 39 Center- 2 1 Right 5 41 Center-Mid 1 1 5 43 Center-Left 2 0 5 45 Back 3 0 63

Table 19. Summary of ASTM slug calorimeter measurements, Test 2-13C.

Incident Energy Time to Max Rack ASTM No. Location (kJ/m2) +/- 18kJ/m2 Temperature (s) +/-

No.

or +/- 4 % 3%

1 A Top 0 N/A 1 B Bottom 1 120 2 C Top 1 123 2 D Bottom 1 121 3 E Top 5 122 This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 3 F Bottom 5 119 4 G Rear 7 122 4 H Front 9 96 5 I Rear 4 108 5 J Front 4 38 Table 20. Summary of Tcap slug measurement, Test 2-13C.

Incident Energy Heat Flux During Total Incident During Arc Phase Rack Tcap Arc (kW/m2) Energy (kJ/m2)

Location (kJ/m2)

No. No. +/- 1.5 kW/m2 +/- 2.4 kJ/m2

+/- 2.4 kJ/m2 or +/- 2.9 % or +/- 5 %

or +/- 5 %

1 2 Top 0.2 0.3 19.8 1 4 Mid-Right 0.1 0.0 16.6 1 6 Mid-Left 0.1 0.1 21.9 1 8 Bottom 0.1 0.2 20.9 2 11 Top 0.0 0.0 2.0 2 13 Mid-Right 0.0 0.1 5.1 2 15 Mid-Left 0.1 0.1 1.1 2 17 Bottom 0.2 0.0 5.4 3 20 Top 0.2 0.3 18.2 3 22 Mid-Right 0.2 0.5 23.4 3 24 Mid-Left 0.2 0.2 25.6 3 26 Bottom 0.2 0.2 19.5 4 29 Front 1.6 3.3 5.6 4 31 Center-Right 2.1 4.3 29.5 4 33 Center-Left 1.4 3.0 21.3 4 35 Back 1.8 3.4 15.7 5 38 Front 0.8 0.9 2.6 5 40 Center-Right 0.6 0.8 2.6 64

Incident Energy Heat Flux During Total Incident During Arc Phase Rack Tcap Arc (kW/m2) Energy (kJ/m2)

Location (kJ/m2)

No. No. +/- 1.5 kW/m2 +/- 2.4 kJ/m2

+/- 2.4 kJ/m2 or +/- 2.9 % or +/- 5 %

or +/- 5 %

5 42 Center-Left 0.6 0.6 3.2 5 44 Back 0.5 0.6 3.5 3.3.1.3. Pressure Measurements This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 The pressure profiles for the first two tenths of a second are shown in Fig. 43. After the initial pressure spike, the pressure rapidly decays to a relative steady state. The peak pressure is higher in the primary cable connection compartment as would be expected since this is the compartment where the arc is initiated. The maximum change in pressure in the main bus compartment is approximately 5 kPa (0.7 psi) above ambient at its peak. The maximum change in pressure in the breaker compartment is approximately 3 kPa (0.4 psi) above ambient. The 0 kPa to 207 kPa (0 psia to 30 psia) and 0 kPa to 345 kPa (0 psia to 50 psia) transducer recordings at a specific location were consistent.

Fig. 43. Pressure measurements from Test 2-13C (breaker compartment (left); Main bus [arcing compartment] (right). Measurement uncertainty +/- 3 percent.

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3.3.1.4. Electrical measurements Test 2-13C used KEMA circuit S07 presented in Appendix C. Full-level circuit checks (calibration tests) were performed prior to the experiment to verify the experimental parameters were acceptable. For this experiment the calibration tests configured the power system to 0.616 kV, 13.5 kA symmetrical, and 35.6 kA peak. Key experimental measurements are presented in Table 21. The KEMA test report identifies this experiment as 190827-7002. Plots of the electrical measurements are presented in Appendix B.

Table 21. Key measurement from Test 2-13C. Measurement uncertainty +/- 3 percent.

This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Phase Units A B C Applied voltage, phase-to-ground kVRMS 356 356 356 Applied voltage, phase-to-phase kVRMS 617 Making current kApeak 25.0 26.1 -34.4 Current, a.c. component, beginning kARMS 13.4 13.2 11.0 Current, a.c. component, middle kARMS 8.92 9.14 10.2 Current, a.c. component, end kARMS 7.93 4.10 8.05 Current, a.c. component, average kARMS 11.5 10.2 9.09 Current, a.c. component, three-phase average kARMS 10.3 Duration s 0.405 0.405 0.404 Arc Energy MJ 1.68 3.4. Test 2-13D - 600 V, 13.5 kA, 2 s duration, breaker stabs (copper) top load section Test 2-13D was performed on August 27, 2019 at 1:25 PM eastern daylight time (EDT). The temperature was approximately 24 °C (75 °F), approximately 62 percent relative humidity and approximately 101.7 kPa of pressure. The weather was cloudy and raining with an 8 km/h (5 mi/h) wind out of the southeast.

The switchgear used in Tests 2-13A, 2-13B, and 2-13C was used again in this experiment. The gear was tested for sufficient insulation resistance between phases and found to be functional. The arcing wire was located around the copper breaker stabs in the main bus section at the top load breaker in the load breaker vertical section. All three phases were shorted with the shorting wire.

Switchgear enclosure was connected to neutral. Generator neutral was tied to ground via impedance. A single 10 AWG bare stranded conductors were used to initiate the arc. The arcing wire installed on the bus and marked up illustrations of the arc wire location is presented in Fig. 44.

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This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Fig. 44. Shorting Wire Location Test 2-13D (Phases left-to-right: A-B-C), photo of arc initiation point (left), elevation view (center), plan view (right). Shorting location shown in red on illustrations.

3.4.1. Observations Observations documented below are based on review of video and thermal imaging that was taken during the experiment. The observations are provided in Table 22 and include an approximate time reference. Corresponding images are provided in Fig. 45.

The experiment did not arc for the planned 2.0 s. Arcing on all three phases was less intermittent than previous experiments but still extinguished at approximately 930 ms. The arc location (on the copper horizontal stabs towards the breaker vs. on the vertical aluminum bus bars) seemed to have no impact on the resultant direction of the arc. The arc still traveled vertically towards the top of the bus bars and established itself on the end of the bus. There was some increased vaporization of the bus bars and thermal impact to the side of the enclosure.

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Table 22. Observations from Test 2-13D.

Time (ms) Observation 0 Initial light observed in top rear louver 66 Initial particle ejecta observed 100 Particle ejecta reaches first instrument rack immediately above enclosure Luminescent flash zone reaches first instrument rack immediately above 216 enclosure 450 Particle ejecta exceeds second instrument rack above enclosure This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 550 Luminescent flash zone expands 734 Particle ejecta continues and luminescent intensity increases 950 Last particle ejecta at arc extinguishment 503 300 NIST data acquisition ends 68

This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Fig. 45. Sequence of Images from Test 2-13D (image time stamps are in seconds).

Photographs of the enclosure following the experiment are presented in Fig. 46 and Fig. 47. The enclosure did not experience a breach.

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Fig. 46. Enclosure Post-Test 2-13D.

70 This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197

This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Fig. 47. Thermal heating on external of load section enclosure adjacent to top of vertical bus bars.

3.4.1.1.Measurements Measurements made during Test 2-13D are presented below. These measurements include:

• Thermal o Heat flux - Plate Thermometers o Incident energy - ASTM Slug Calorimeter o Heat flux, incident energy - Tcap Slug Calorimeter

• Pressure o Internal pressure

• Electrical 3.4.1.2.Thermal Measurements Thermal measurements from the active instruments are reported below. These include PT measurements (Table 23), ASTM Slug Calorimeter measurements (Table 24), and Tcap slug measurements (Table 25). The maximum reading is identified with bold text. For some sensors, the EMI interfered with the thermal measurement. These are listed as -- and noted with EMI.

Due to the short duration of the arc and no breaching of the exterior skin of the switchgear, the thermal exposures measured outside of the switchgear were very small.

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Table 23. Summary of plate thermometer measurements Test 2-13D.

Max Heat Average Heat Flux Rack Plate Flux (kW/m2) During Arc (kW/m2)

Location Comment No. No. +/- 1 kW/m2 +/- 1 kW/m2 or +/- 5 % or +/- 5 %

1 1 Top 8 1 1 3 Mid-Right 2 0 1 5 Mid-Center 0 EMI 1 7 Mid-Left 2 0 This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 1 9 Bottom 1 0 2 10 Top 1 0 2 12 Mid-Right 1 0 2 14 Mid-Center 0 EMI 2 16 Mid-Left 1 0 2 18 Bottom 0 EMI 3 19 Top 8 1 3 21 Mid-Right 3 1 3 23 Mid-Center 4 1 3 25 Mid-Left 3 1 3 27 Bottom 1 0 4 28 Front 15 3 4 30 Center- 19 6 Right 4 32 Center-Mid 20. 7 4 34 Center-Left 14 6 4 36 Back 27 5 5 37 Front 10. 3 5 39 Center- 7 2 Right 5 41 Center-Mid 6 2 5 43 Center-Left 3 1 5 45 Back 12 2 72

Table 24. Summary of ASTM slug calorimeter measurements, Test 2-13D.

Incident Energy Time to Max Rack ASTM No. Location (kJ/m2) +/- 18kJ/m2 Temperature (s) +/-

No.

or +/- 4 % 3%

1 A Top 3 206 1 B Bottom 2 204 2 C Top 3 2 2 D Bottom 0 N/A 3 E Top 16 201 This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 3 F Bottom 13 197 4 G Rear 18 164 4 H Front 22 207 5 I Rear 11 140 5 J Front 7 211 Table 25. Summary of Tcap slug measurement, Test 2-13D.

Incident Energy Heat Flux During Total Incident During Arc Phase Rack Tcap Arc (kW/m2) Energy (kJ/m2)

Location (kJ/m2)

No. No. +/- 1.5 kW/m2 +/- 2.4 kJ/m2

+/- 2.4 kJ/m2 or +/- 2.9 % or +/- 5 %

or +/- 5 %

1 2 Top 0.4 0.8 5.8 1 4 Mid-Right 0.4 0.5 4.2 1 6 Mid-Left 2.4 0.6 4.1 1 8 Bottom 0.4 0.6 3.8 2 11 Top 1.6 0.0 2.0 2 13 Mid-Right 0.1 0.1 0.3 2 15 Mid-Left 0.3 0.1 0.4 2 17 Bottom 0.0 0.0 0.9 3 20 Top 1.0 1.7 56.1 3 22 Mid-Right 0.7 1.6 58.3 3 24 Mid-Left 0.6 1.2 56.5 3 26 Bottom 0.4 0.7 49.0 4 29 Front 6.7 12.3 70.8 4 31 Center-Right 5.2 10.3 60.6 4 33 Center-Left 7.2 12.5 64.8 4 35 Back 4.7 8.8 66.5 5 38 Front 1.2 2.8 21.6 5 40 Center-Right 1.4 2.8 24.8 73

Incident Energy Heat Flux During Total Incident During Arc Phase Rack Tcap Arc (kW/m2) Energy (kJ/m2)

Location (kJ/m2)

No. No. +/- 1.5 kW/m2 +/- 2.4 kJ/m2

+/- 2.4 kJ/m2 or +/- 2.9 % or +/- 5 %

or +/- 5 %

5 42 Center-Left 1.2 2.6 16.2 5 44 Back 1.2 1.8 13.6 3.4.1.3. Pressure Measurements This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 The pressure profiles for the first two tenths of a second are shown in Fig. 48. After the initial pressure spike, the pressure rapidly decays to a relative steady state. The peak pressure is higher in the primary cable connection compartment as would be expected since this is the compartment where the arc is initiated. The maximum change in pressure in the main bus compartment is approximately 7 kPa (0.8 psi) above ambient at its peak. The maximum change in pressure in the breaker compartment is approximately 3 kPa (0.4 psi) above ambient. The 0 kPa to 207 kPa (0 psia to 30 psia) and 0 kPa to 345 kPa (0 psia to 50 psia) transducer recordings at a specific location were consistent.

Fig. 48. Pressure measurements from Test 2-13D (breaker compartment (left); Main bus [arcing compartment] (right). Measurement uncertainty +/- 3 percent.

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3.4.1.4. Electrical measurements Test 2-13C used KEMA circuit S07 presented in Appendix C. Full-level circuit checks (calibration tests) were performed prior to the experiment to verify the experimental parameters were acceptable. For this experiment the calibration tests configured the power system to 0.616 kV, 13.5 kA symmetrical, and 35.6 kA peak. The KEMA report identifies this experiment as 190827-7003. Key experimental measurements are presented in Table 26. Plots of the electrical measurements are presented in Appendix B.

Table 26. Key measurement from Test 2-13D. Measurement uncertainty +/- 3 percent.

This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Phase Units A B C Applied voltage, phase-to-ground kVRMS 356 356 356 Applied voltage, phase-to-phase kVRMS 617 Making current kApeak 24.7 28.4 -34.3 Current, a.c. component, beginning kARMS 13.4 13.5 12.2 Current, a.c. component, middle kARMS 9.05 13.7 11.8 Current, a.c. component, end kARMS 10.9 8.03 8.49 Current, a.c. component, average kARMS 11.2 10.1 9.88 Current, a.c. component, three-phase average kARMS 10.4 Duration s 0.924 0.924 0.924 Arc Energy MJ 4.21 3.5. Test 2-13E - 600 V, 13.5 kA, 2 s duration, breaker stabs (copper) middle breaker cubicle Test 2-13E was performed on August 28, 2019 at 9:33 AM eastern daylight time (EDT). The temperature was approximately 26 °C (78 °F), approximately 62 percent relative humidity and approximately 101.2 kPa of pressure. The weather was mostly cloudy with an 8 km/h (5 mi/h) wind out of the east.

The switchgear used in Tests 2-13A, 2-13B, 2-13C and 2-13D was used again in this experiment.

The gear was tested for sufficient insulation resistance between phases and found to be functional.

The arcing wire was located around the copper breaker stabs in the second from bottom breaker cubicle in the load breaker vertical section. The arc was initiated on the bus bar stabs (copper) and wrapped through the opening in the stab connections as shown in Fig. 49. This arc was initiated on the breaker cubicle side of the enclosure with the power direction facing the front of the enclosures (rear of KEMA test cell) into the breaker itself. All three phases were shorted with the shorting wire. The current transformers were removed to aid the installation of the arc wire. After installation of the arc wire, the breaker was racked in but not closed. Switchgear enclosure was connected to neutral. Generator neutral was tied to ground via impedance. A single 10 AWG bare stranded conductors were used to initiate the arc. The arcing wire installed on stabs and marked up illustrations of the arc wire location is presented in Fig. 49.

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This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Fig. 49. Shorting Wire Location Test 2-13E (Phases left-to-right: A-B-C), photo of arc initiation point (left), elevation view (center), plan view (right).

Shorting location shown in red on illustrations.

3.5.1. Observations Observations documented below are based on review of video and thermal imaging that was taken during the experiment. The observations are provided in Table 27 and include an approximate time reference. Corresponding images are provided in Fig. 50 and Fig. 51.

The experiment did sustain for the planned 2.0 s. The intermittent arcing observed in previous experiments was not observed during this experiment. The arc was consistent and was extinguished by the laboratory at the end of the planned experiment duration. The arc vaporized some of the breaker finger cluster connection pieces as well as some of the breaker structure itself. The breaker caught on fire and required manual suppression. No enclosure doors opened due to pressure challenges; however, two doors were manually opened to find and fight the fire.

The arc location and direction of the power supply did not facilitate the involvement of any of the aluminum within the enclosure.

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Table 27. Observations from Test 2-13E.

Time (ms) Observation 0 Start of experiment 100 Initial gasses escaping top of enclosure 250 Gasses reaching first instrument rack above enclosure 316 Initial flames emerge from top of enclosure 1 034 Flames reach first instrument rack above enclosure 1 184 Flame regions expand vertically, and gas region expands horizontally This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 1 501 Flame region at steady-state 1 901 Flame region 100 ms prior to end of experiment 2 001 Flame region at end of experiment 2 168 Post-arc combustion 648 800 NIST data acquisition ends Fig. 50. Sequence of Images from first have of Test 2-13E (image time stamps are in seconds).

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This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Fig. 51. Sequence of Images from second half of Test 2-13E (image time stamps are in seconds).

Photographs of the enclosure following the experiment are presented in Fig. 52, Fig. 53, and Fig. 54. The enclosure did not experience a breach.

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This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Fig. 52. Switchgear stabs post-experiment.

Fig. 53. Breaker post-experiment. (front/side view (left), top/rear view showing breaker contact fingers missing (right)).

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This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Fig. 54. Main bus bar post-experiment.

3.5.1.1.Measurements Measurements made during Test 2-13E are presented below. These measurements include:

• Thermal o Heat flux - Plate Thermometers o Incident energy - ASTM Slug Calorimeter o Heat flux, incident energy - Tcap Slug Calorimeter

• Pressure o Internal pressure

• Electrical 3.5.1.2.Thermal Measurements Thermal measurements from the active instruments are reported below. These include PT 80

measurements (Table 28), ASTM Slug Calorimeter measurements (Table 29), and Tcap slug measurements (Table 30). The maximum reading is identified with bold text. For some sensors, the EMI interfered with the thermal measurement. These are listed as -- and noted with EMI.

For some measurements, the EMI magnitude was of the same order as the signal. These are listed as -- and noted with EMI S/N.

The thermal exposures measured outside of the switchgear were greater than the proceeding experiments due to the flames issuing from the vents at the top of the electrical enclosure.

Table 28. Summary of plate thermometer measurements Test 2-13E.

This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Max Heat Flux Average Heat Flux Rack (kW/m2) During Arc (kW/m2)

Plate No. Location Comment No. +/- 1 kW/m2 +/- 1 kW/m2 or +/- 5 % or +/- 5 %

1 1 Top 5 1 1 3 Mid-Right 2 0 1 5 Mid- 1 0 Center 1 7 Mid-Left 3 0 1 9 Bottom 0 EMI 2 10 Top 8 3 2 12 Mid-Right 4 2 2 14 Mid- 16 3 Center 2 16 Mid-Left 12 2 2 18 Bottom 18 3 3 19 Top 8 2 3 21 Mid-Right 2 1 3 23 Mid- 4 1 Center 3 25 Mid-Left 3 1 3 27 Bottom 3 1 4 28 Front 22 7 4 30 Center- 21 7 Right 4 32 Center- 71 30.

Mid 4 34 Center- 12 6 Left 4 36 Back 7 2 5 37 Front 17 4 81

Max Heat Flux Average Heat Flux Rack (kW/m2) During Arc (kW/m2)

Plate No. Location Comment No. +/- 1 kW/m2 +/- 1 kW/m2 or +/- 5 % or +/- 5 %

5 39 Center- 7 3 Right 5 41 Center- 19 10.

Mid 5 43 Center- 10. 4 Left This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 5 45 Back 7 1 Table 29. Summary of ASTM slug calorimeter measurements, Test 2-13E.

Time to Max Rack ASTM Incident Energy (kJ/m2) +/-

Location Temperature (s) +/-

No. No. 18kJ/m2 or +/- 4 %

3%

1 A Top 3 606 1 B Bottom 1 596 2 C Top 10 542 2 D Bottom 10 560 3 E Top 10 630 3 F Bottom 17 644 4 G Rear 90 9 4 H Front 36 142 5 I Rear 25 13 5 J Front 19 10 82

Table 30. Summary of Tcap slug measurement, Test 2-13E.

Heat Flux Incident Energy Total Incident During Arc During Arc Energy Rack Tcap Location (kW/m2) Phase (kJ/m2) (kJ/m2) Comment No. No.

+/- 1.5 kW/m2 +/- 2.4 kJ/m2 +/- 2.4 kJ/m2 or +/- 2.9 % or +/- 5 % or +/- 5 %

1 2 Top 0.4 14.9 EMI S/N 1 4 Mid-Right 0.0 0.0 0.4 1 6 Mid-Left 1.1 0.0 6.7 This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 1 8 Bottom 0.0 -0.1 0.1 2 11 Top 3.2 30.8 EMI S/N 2 13 Mid-Right 2.6 4.2 36.2 2 15 Mid-Left 1.9 3.1 25.7 2 17 Bottom 3.3 34.7 EMI S/N 3 20 Top 1.1 1.6 29.9 3 22 Mid-Right 1.0 1.1 30.7 3 24 Mid-Left 1.0 1.9 44.9 3 26 Bottom 0.6 0.5 39.8 4 29 Front 64.1 87.4 262.6 4 31 Center- 15.4 19.7 117.1 Right 4 33 Center- 21.0 30.0 164.9 Left 4 35 Back 9.0 90.2 EMI S/N 5 38 Front 12.4 16.6 57.3 5 40 Center- 5.2 5.8 29.9 Right 5 42 Center- 8.3 10.7 42.5 Left 5 44 Back 2.1 26.9 EMI S/N 3.5.1.3. Pressure Measurements The pressure profiles for the first two tenths of a second are shown in Fig. 55. After the initial pressure spike, the pressure rapidly decays to a relative steady state. The peak pressure is higher in the primary cable connection compartment as would be expected since this is the compartment where the arc is initiated. The maximum change in pressure in the main bus compartment is approximately 6 kPa (0.8 psi) above ambient at its peak. The maximum change in pressure in the breaker compartment is approximately 3 kPa (0.4 psi) above ambient. The 0 kPa to 207 kPa (0 psia to 30 psia) and 0 kPa to 345 kPa (0 psia to 50 psia) transducer recordings at a specific location were consistent.

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This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Fig. 55. Pressure measurements from Test 2-13E (breaker compartment (left); Main bus [arcing compartment] (right). Measurement uncertainty +/- 3 percent.

3.5.1.4. Electrical measurements Test 2-13E used KEMA circuit S07 presented in Appendix C. Full-level circuit checks (calibration tests) were performed prior to the experiment to verify the experimental parameters were acceptable. For this experiment the calibration tests configured the power system to 0.616 kV, 13.5 kA symmetrical, and 35.6 kA peak. The KEMA report identifies this experiment as 190827-7004. Key experimental measurements are presented in Table 31. Plots of the electrical measurements are presented in Appendix B.

Table 31. Key measurement from Test 2-13E. Measurement uncertainty +/- 3 percent.

Phase Units A B C Applied voltage, phase-to-ground kVRMS 356 356 356 Applied voltage, phase-to-phase kVRMS 617 Making current kApeak 24.9 28.4 -34.3 Current, a.c. component, beginning kARMS 12.6 13.5 11.6 Current, a.c. component, middle kARMS 10.4 10.5 9.79 Current, a.c. component, end kARMS 10.2 9.35 9.26 Current, a.c. component, average kARMS 11.1 10.8 10.0 Current, a.c. component, three-phase average kARMS 10.6 Duration s 2.06 2.06 2.06 Arc Energy MJ 9.64 84

3.6. Test 2-13F - 480 V, 13.5 kA, 2 s duration, main bus, load section Test 2-13E was performed on August 28, 2019 at 9:33 AM eastern daylight time (EDT). The temperature was approximately 26 °C (78 °F), approximately 62 percent relative humidity and approximately 100.9 kPa of pressure. The weather was mostly cloudy with an 8 km/h (5 mi/h) wind out of the east.

The switchgear used in Tests 2-13A, 2-13B, 2-13C, 2-13D and 2-13E was used again in this experiment. The gear was tested for sufficient insulation resistance between phases and found to be functional. The arcing wire was located around the vertical main bus work at the bottom of the This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 load breaker vertical section. All three phases were shorted with the shorting wire. Switchgear enclosure was connected to neutral. Generator neutral was tied to ground via impedance. The zero-sequence voltage was removed from all three voltage phases in the plot above. The arcing wire installed on the main bus and marked up illustrations of the arc wire location is presented in Fig. 56.

Fig. 56. Shorting Wire Location Test 2-13F (Phases left-to-right: A-B-C), photo of arc initiation point (left), elevation view (center), plan view (right). Shorting location shown in red on illustrations.

3.6.1. Observations Observations documented below are based on review of video and thermal imaging that was taken during the experiment. The observations are provided in Table 32 and include an approximate time reference. Corresponding images are provided in Fig. 57.

The arc did not sustain for the expected 2.0 s duration. The final arc extinguished at 1 550 ms.

Intermittent arcing was observed but not as severe as in previous experiments on the main bus.

There were a number of extinguishments and weak re-strikes, but none lasted longer than 1/2 a cycle up until phase B and C concurrently extinguished at 1 320 ms. Phase A remained arcing current until final arc extinguishment at 1 550 ms. The arc was initiated in the bottom of the left side of the enclosure and held for 1 300 ms. It appears from looking at the high-speed thermal imaging camera that the arc held for roughly 900 ms on the left bus bar run then the arc migrated over to the right hand side of the enclosure where the arc extinguished. The A phase held in the 85

arc for approximately 200 ms after the migration until the grounding cable disconnected from the cabinet as seen in Fig. 59.

Table 32. Observations from Test 2-13F.

Time (ms) Observation 0 Initial light observed in bottom rear louver 150 Initial gasses exiting bottom rear louver 350 Particle ejecta reaching rear instrumentation rack 500 Gasses expanding and encompassing rear instrumentation rack This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 750 Gas and flame regions expanding 1 000 Gasses reach first instrumentation rack above enclosure 1 518 Final arc flash observed externally in load section (lower left)

Post arc gasses and particle ejecta exceeding instrumentation rack to side of 1 634 load vertical section (left) 319 900 NIST data acquisition ends 86

Fig. 57. Sequence of Images from Test 2-13F (image time stamps are in seconds).

87 This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197

Photographs of the enclosure following the experiment are presented in Fig. 58 and Fig. 59. The enclosure did not experience a breach.

This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Fig. 58. Enclosure Post-Test 2-13F.

88

This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Fig. 59. Post-experiment image of enclosure grounding cable disconnected from enclosure due to current flow through ground circuit.

3.6.1.1.Measurements Measurements made during Test 2-13F are presented below. These measurements include:

• Thermal o Heat flux - Plate Thermometers o Incident energy - ASTM Slug Calorimeter o Heat flux, incident energy - Tcap Slug Calorimeter

• Pressure o Internal pressure

• Electrical 89

3.6.1.2. Thermal Measurements Thermal measurements from the active instruments are reported below in Table 33 through Table 35. These include PT measurements, ASTM Slug Calorimeter measurements, and Tcap slug measurements. The maximum reading is identified with bold text. For some sensors, the EMI interfered with the thermal measurement. These are listed as -- and noted with EMI. For some measurements, the EMI magnitude was of the same order as the signal. These are listed as --

and noted with EMI S/N.

Table 33. Summary of plate thermometer measurements Test 2-13F.

This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Max Heat Flux Average Heat Flux Rack (kW/m2) During Arc (kW/m2)

Plate No. Location Comment No. +/- 1 kW/m2 +/-1 kW/m2 or +/- 5 % or +/- 5 %

1 1 Top 56 15 1 3 Mid-Right 53 13 1 5 Mid- 115 24 Center 1 7 Mid-Left 91 15 1 9 Bottom 155 48 2 10 Top 1 0 2 12 Mid-Right 1 0 2 14 Mid- 0 EMI Center 2 16 Mid-Left 1 0 2 18 Bottom 0 EMI 3 19 Top 6 1 3 21 Mid-Right 7 2 3 23 Mid- 7 1 Center 3 25 Mid-Left 4 1 3 27 Bottom 6 2 4 28 Front 5 1 4 30 Center- 4 1 Right 4 32 Center- 6 1 Mid 4 34 Center- 5 1 Left 4 36 Back 5 2 5 37 Front 0 EMI 90

Max Heat Flux Average Heat Flux Rack (kW/m2) During Arc (kW/m2)

Plate No. Location Comment No. +/- 1 kW/m2 +/-1 kW/m2 or +/- 5 % or +/- 5 %

5 39 Center- 3 1 Right 5 41 Center- 2 1 Mid 5 43 Center- 2 1 Left This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 5 45 Back 6 1 Table 34. Summary of ASTM slug calorimeter measurements, Test 2-13F.

Incident Energy Time to Max Rack ASTM No. Location (kJ/m2) +/- 18kJ/m2 Temperature (s) +/-

No.

or +/- 4 % 3%

1 A Top 37 5 1 B Bottom 61 2 2 C Top 4 287 2 D Bottom 3 280 3 E Top 6 181 3 F Bottom 9 275 4 G Rear 8 183 4 H Front 9 259 5 I Rear 5 186 5 J Front 6 259 Table 35. Summary of Tcap slug measurement, Test 2-13F.

Heat Flux Incident Energy Total Incident During Arc During Arc Rack Tcap Energy (kJ/m2)

Location (kW/m2) Phase (kJ/m2) Comment No. No. +/- 2.4 kJ/m2

+/- 1.5 kW/m2 +/- 2.4 kJ/m2 or +/- 5 %

or +/- 2.9 % or +/- 5 %

1 2 Top 45.3 67.1 EMI 1 4 Mid-Right 40.9 68.2 EMI 1 6 Mid-Left 44.0 70.3 EMI 1 8 Bottom 34.2 60.9 87.3 2 11 Top 0.1 8.0 EMI S/N 2 13 Mid-Right 0.2 0.2 7.3 2 15 Mid-Left 0.9 0.1 7.3 91

Heat Flux Incident Energy Total Incident During Arc During Arc Rack Tcap Energy (kJ/m2)

Location (kW/m2) Phase (kJ/m2) Comment No. No. +/- 2.4 kJ/m2

+/- 1.5 kW/m2 +/- 2.4 kJ/m2 or +/- 5 %

or +/- 2.9 % or +/- 5 %

2 17 Bottom 1.6 0.1 9.2 3 20 Top 1.4 1.8 12.1 3 22 Mid-Right 2.3 3.2 19.8 3 24 Mid-Left 1.1 1.7 8.9 This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 3 26 Bottom 1.8 2.0 23.0 4 29 Front 1.4 1.5 17.3 4 31 Center- 1.1 21.0 EMI S/N Right 4 33 Center- 0.8 1.1 14.4 Left 4 35 Back 0.4 1.4 22.0 5 38 Front 0.9 0.4 12.3 5 40 Center- 0.4 0.6 8.1 Right 5 42 Center- 0.8 0.8 9.1 Left 5 44 Back 0.5 10.9 EMI S/N 3.6.1.3. Pressure Measurements The pressure profiles for the first two tenths of a second are shown in Fig. 60. After the initial pressure spike, the pressure rapidly decays to a relative steady state. The peak pressure is higher in the primary cable connection compartment as would be expected since this is the compartment where the arc is initiated. The maximum change in pressure in the main bus compartment is approximately 4 kPa (0.6 psi) above ambient at its peak. The maximum change in pressure in the breaker compartment is approximately 2 kPa (0.3 psi) above ambient. The 0 kPa to 207 kPa (0 psia to 30 psia) and 0 kPa to 345 kPa (0 psia to 50 psia) transducer recordings at a specific location were consistent.

92

This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Fig. 60. Pressure measurements from Test 2-13F (breaker compartment (left); Main bus [arcing compartment] - (right)). Measurement uncertainty +/- 3 percent.

3.6.1.4. Electrical measurements Test 2-13F used KEMA circuit S06 presented in Appendix C. Full-level circuit checks (calibration tests) were performed prior to the experiment to verify the experimental parameters were acceptable. For this experiment the calibration tests configured the power system to 0.616 kV, 13.5 kA symmetrical, and 35.6 kA peak. The KEMA report identifies this experiment as 190828-7001. Key experimental measurements are presented in Table 36. Plots of the electrical measurements are presented in Appendix B.

Table 36. Key measurement from Test 2-13F. Measurement uncertainty +/- 3 percent.

Phase Units A B C Applied voltage, phase-to-ground kVRMS 282 282 282 Applied voltage, phase-to-phase kVRMS 488 Making current kApeak 24.7 28.4 -34.2 Current, a.c. component, beginning kARMS 13.1 13.6 12.8 Current, a.c. component, middle kARMS 8.32 9.92 7.61 Current, a.c. component, end kARMS 9.46 10.4 8.55 Current, a.c. component, average kARMS 10.3 9.95 9.26 Current, a.c. component, three-phase average kARMS 9.84 Duration s 1.55 1.32 1.32 Arc Energy MJ 5.44 93

3.7. Test 2-13G - 600 V, 13.5 kA, 2 s duration, main bus, Supply section Test 2-13E was performed on August 28, 2019 at 3:36 PM eastern daylight time (EDT). The temperature was approximately 28 °C (82 °F), approximately 84 percent relative humidity and approximately 100.7 kPa of pressure. The weather was cloudy with a 13 km/h (8 mi/h) wind out of the west.

The switchgear used in Tests 2-13A, 2-13B, 2-13C, 2-13D, 2-13E and 2-13F was used again in this experiment. The gear was tested for sufficient insulation resistance between phases and found to be functional. The arcing wire was located around the vertical main bus work at the bottom of This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 the supply breaker vertical section as shown in Fig. 61. All three phases were shorted with the shorting wire. Switchgear enclosure was connected to neutral. Generator neutral was tied to ground via impedance.

Fig. 61. Shorting Wire Location Test 2-13G (Phases left-to-right: A-B-C), photo of arc initiation point (left), elevation view (center), plan view (right). Shorting location shown in red on illustrations.

3.7.1. Observations Observations documented below are based on review of video and thermal imaging that was taken during the experiment. The observations are provided in Table 37 and include an approximate time reference. Corresponding images are provided in Fig. 62.

The arc did sustain for the expected 2.0 s duration. The final arc extinguished at 2 050 ms. There was no arc extinguishment on any phase; however, phase B demonstrated a slow re-strike around 229 ms. There was arc migration between the load and supply vertical sections, first from the supply to the load and then back to the supply. The post-experiment inspection looks like the aluminum became involved in the event and white powder as well as particulate deposition towards the instrumentation rack were observed.

94

Table 37. Observations from Test 2-13G.

Time (ms) Observation 0 Initial light observed in bottom rear louver 183 Particle ejecta observed from bottom louvers 500 Particle ejecta observed in top louvers and reach back instrumentation rack 750 Gasses expand and exceed back instrumentation rack 1 016 Gasses expand to top instrumentation rack 1 501 Rear instrumentation rack fully enveloped in hot gasses This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 2 001 Flame sheet observed exiting lower louvers 2 185 Post-experiment final particle ejecta and combustion 641 000 NIST data acquisition ends 95

Fig. 62. Sequence of Images from Test 2-13G (image time stamps are in seconds).

96 This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197

Photographs of the enclosure following the experiment is presented in Fig. 63. The enclosure did not experience a breach.

This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Fig. 63. Enclosure Post-Test 2-13G.

3.7.1.1.Measurements Measurements made during Test 2-13G are presented below. These measurements include:

• Thermal o Heat flux - Plate Thermometers o Incident energy - ASTM Slug Calorimeter o Heat flux, incident energy - Tcap Slug Calorimeter

• Pressure o Internal pressure

• Electrical 97

3.7.1.2. Thermal Measurements Thermal measurements from the active instruments are reported below in Table 38 through Table 40. These include PT measurements, ASTM Slug Calorimeter measurements, and Tcap slug measurements. The maximum reading is identified with bold text. For some sensors, the EMI interfered with the thermal measurement. These are listed as -- and noted with EMI. For some measurements, the EMI magnitude was of the same order as the signal. These are listed as --

and noted with EMI S/N.

This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Table 38. Summary of plate thermometer measurements Test 2-13G.

Max Heat Flux Average Heat Flux Rack Plate (kW/m2) During Arc (kW/m2)

Location Comment No. No. +/- 1 kW/m2 +/- 1 kW/m2 or +/- 5 % or +/- 5 %

1 1 Top 53 25 1 3 Mid-Right 78 29 1 5 Mid-Center 117 45 1 7 Mid-Left 166 28 1 9 Bottom 176 70.

2 10 Top 2 0 2 12 Mid-Right 2 1 2 14 Mid-Center 0 EMI 2 16 Mid-Left 2 0 2 18 Bottom 2 0 3 19 Top 9 3 3 21 Mid-Right 16 5 3 23 Mid-Center 15 3 3 25 Mid-Left 8 2 3 27 Bottom 15 4 4 28 Front 3 1 4 30 Center-Right 13 2 4 32 Center-Mid 12 2 4 34 Center-Left 6 2 4 36 Back 28 4 5 37 Front 5 1 5 39 Center-Right 14 1 5 41 Center-Mid 6 1 5 43 Center-Left 4 1 5 45 Back 12 2 98

Table 39. Summary of ASTM slug calorimeter measurements, Test 2-13G.

Incident Energy Time to Max Rack ASTM No. Location (kJ/m2) +/- 18kJ/m2 Temperature (s) +/-

No.

or +/- 4 % 3%

1 A Top 75 5 1 B Bottom 110 3 2 C Top 1 5 2 D Bottom 1 6 3 E Top 10 9 This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 3 F Bottom 10 281 4 G Rear 17 50 4 H Front 30 7 5 I Rear 10 51 5 J Front 11 9 Table 40. Summary of Tcap slug measurement, Test 2-13G.

Heat Flux Incident Energy Total Incident During Arc During Arc Rack Tcap Energy (kJ/m2)

Location (kW/m2) Phase (kJ/m2) Comment No. No. +/- 2.4 kJ/m2

+/- 1.5 kW/m2 +/- 2.4 kJ/m2 or +/- 5 %

or +/- 2.9 % or +/- 5 %

1 2 Top 81.0 106.6 EMI 1 4 Mid-Right 57.0 83.1 118.5 1 6 Mid-Left 57.6 81.3 111.8 1 8 Bottom 56.6 101.1 141.1 2 11 Top 1.8 0.3 3.7 2 13 Mid-Right 0.1 0.2 0.6 2 15 Mid-Left 0.2 0.1 0.5 2 17 Bottom 2.4 0.3 3.1 3 20 Top 3.0 3.5 23.9 3 22 Mid-Right 4.3 6.7 34.4 3 24 Mid-Left 2.3 3.7 29.1 3 26 Bottom 3.5 36.4 EMI S/N 4 29 Front 2.8 35.0 EMI S/N 4 31 Center- 1.0 1.6 77.2 Right 4 33 Center-Left 2.8 44.0 EMI S/N 4 35 Back 2.4 2.8 107.0 5 38 Front 0.7 1.5 18.5 99

5 40 Center- 1.4 27.9 EMI S/N Right 5 42 Center-Left 1.7 16.5 EMI S/N 5 44 Back 0.8 1.2 32.4 3.7.1.3. Pressure Measurements The pressure profiles for the first two tenths of a second are shown in Fig. 64. After the initial This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 pressure spike, the pressure rapidly decays to a relative steady state. The peak pressure is higher in the primary cable connection compartment as would be expected since this is the compartment where the arc is initiated. The maximum change in pressure in the main bus compartment is approximately 7 kPa (1.0 psi) above ambient at its peak. The maximum change in pressure in the breaker compartment is approximately 3 kPa (0.5 psi) above ambient. The 0 kPa to 207 kPa (0 psia to 30 psia) and 0 kPa to 345 kPa (0 psia to 50 psia) transducer recordings at a specific location were consistent.

Fig. 64. Pressure measurements from Test 2-13G (breaker compartment (left); Main bus [arcing compartment] - (right)). Measurement uncertainty +/- 3 percent.

3.7.1.4. Electrical measurements Test 2-13G used KEMA circuit S07 presented in Appendix C. Full-level circuit checks (calibration tests) were performed prior to the experiment to verify the experimental parameters were acceptable. For this experiment the calibration tests configured the power system to 100

0.616 kV, 13.5 kA symmetrical, and 35.6 kA peak. The KEMA report identifies this experiment as 190828-7002. Key experimental measurements are presented in Table 41. Plots of the electrical measurements are presented in Appendix B.

Table 41. Key measurement from Test 2-13G. Measurement uncertainty +/- 3 percent.

Phase Units A B C Applied voltage, phase-to-ground kVRMS 356 356 356 Applied voltage, phase-to-phase kVRMS 617 Making current kApeak 25.1 26.6 -33.8 This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Current, a.c. component, beginning kARMS 14.0 13.1 13.0 Current, a.c. component, middle kARMS 9.62 12.1 9.18 Current, a.c. component, end kARMS 12.1 8.87 11.1 Current, a.c. component, average kARMS 12.3 10.8 11.0 Current, a.c. component, three-phase average kARMS 11.4 Duration s 2.04 2.04 2.04 Arc Energy MJ 10.40 3.8. Test 2-18A - 480 V, 25 kA, 8 s duration, main bus, load section Test 2-18A was performed on August 29, 2019 at 11:22 AM eastern daylight time (EDT). The temperature was approximately 26 °C (79 °F), approximately 40 percent relative humidity and approximately 101.1 kPa of pressure. The weather was fair with a 19 km/h (12 mi/h) wind out of the north.

The arcing wire was located around the vertical main bus work at the bottom of the load breaker vertical section as shown in Fig. 65. All three phases were shorted with the shorting wire.

Switchgear enclosure was connected to neutral. Generator neutral was tied to ground via impedance.

101

This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Fig. 65. Shorting Wire Location Test 2-18A (Phases left-to-right: A-B-C), photo of arc initiation point (left), elevation view (center), plan view (right). Shorting location shown in red on illustrations.

3.8.1. Observations Observations documented below are based on review of video and thermal imaging that was taken during the experiment. The observations are provided in Table 42 and include an approximate time reference. Corresponding images are provided in Fig. 66 and Fig. 67.

The arc did not sustain for the expected 8.0 s duration. The final arc extinguished at 2 020 ms.

There were arc extinguishment on Phase B and C near 633 ms and was concurrent for 22 ms.

102

Table 42. Observations from Test 2-18A.

Time (ms) Observation 0 Initial light observed in bottom rear louver Particle ejecta observed exiting bottom of supply vertical section, hot gasses 166 exiting rear of enclosure and exceeding the rear instrumentation rack location 316 Particle eject exiting top louvers Arc location observed in top of supply vertical section (distinct relocation from 417 initial location = bottom of supply vertical section)

This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 517 Arc location moves briefly to load vertical section (left)

Gasses reach first instrumentation rack above enclosure and rack to left of load 617 vertical section. Particle ejecta reaches top instrumentation rack above enclosure 834 Arc location move to bottom of switchgear Arc moves to lower portion of supply section. Gasses and particle ejecta 1 016 observed exceeding all instrumentation rack locations 1 718 Arc moves to upper portion of load section 2 102 Final particle ejecta post-experiment 443 800 NIST data acquisition ends 103

This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Fig. 66. Sequence of Images from Test 2-18A up to 0.617 s (image time stamps are in seconds).

104

This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Fig. 67. Sequence of Images from Test 2-18A from 0.617 s to end of experiment (image time stamps are in seconds).

Photographs of the enclosure following the experiment are presented in Fig. 68 and Fig. 69. The enclosure did not experience a breach.

Fig. 68. Enclosure Post-Test 2-18A. Top of main bus, Load side (left), supply side (right).

105

This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Fig. 69. Post-experiment image of enclosure breach and thermal effects on supply side of gear.

106

3.8.1.1.Measurements Measurements made during Test 2-18A are presented below. These measurements include:

• Thermal o Heat flux - Plate Thermometers o Incident energy - ASTM Slug Calorimeter o Heat flux, incident energy - Tcap Slug Calorimeter

• Pressure This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 o Internal pressure

• Electrical 3.8.1.2. Thermal Measurements Thermal measurements from the active instruments are reported below in Table 43 through Table 45. These include PT measurements, ASTM Slug Calorimeter measurements, and Tcap slug measurements. The maximum reading is identified with bold text. For some sensors, the EMI interfered with the thermal measurement. These are listed as -- and noted with EMI. For some measurements, the EMI magnitude was of the same order as the signal. These are listed as --

and noted with EMI S/N.

Table 43. Summary of plate thermometer measurements Test 2-18A.

Max Heat Flux Average Heat Flux Plate (kW/m2) During Arc (kW/m2)

Location Comment No. +/- 1 kW/m2 +/- 1 kW/m2 or +/- 5 % or +/- 5 %

1 Top 84 6 3 Mid-Right 62 7 5 Mid-Center 93 9 7 Mid-Left 133 8 9 Bottom 152 17 10 Top 11 1 12 Mid-Right 3 0 14 Mid-Center 9 0 16 Mid-Left 3 0 18 Bottom 0 EMI 19 Top 35 3 21 Mid-Right 18 2 23 Mid-Center 15 2 25 Mid-Left 21 1 107

Max Heat Flux Average Heat Flux Plate (kW/m2) During Arc (kW/m2)

Location Comment No. +/- 1 kW/m2 +/- 1 kW/m2 or +/- 5 % or +/- 5 %

27 Bottom 10. 1 28 Top 29 3 30 Mid-Right 118 9 This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 32 Mid-Center 129 10.

34 Mid-Left 143 11 36 Bottom 135 9 37 Front 27 2 39 Center-Right 30. 3 41 Center-Mid 23 4 43 Center-Left 20. 3 45 Back 20. 4 46 Front 23 2 48 Center-Bottom 8 1 50 Center-Mid 6 1 52 Center-Top 7 1 54 Back 5 0 Table 44. Summary of ASTM slug calorimeter measurements, Test 2-18A.

Incident Energy Time to Max Rack ASTM No. Location (kJ/m2) +/- 18kJ/m2 Temperature (s) +/-

No.

or +/- 4 % 3%

1 A Top 58 4 1 B Bottom 83 3 2 C Top 5 434 2 D Bottom 4 430 3 E Top 27 335 3 F Bottom 24 436 4 G Rear 65 179 4 H Front 92 8 5 I Rear 27 250 5 J Front 29 4 6 K Rear 15 277 6 L Front 16 422 108

Table 45. Summary of Tcap slug measurement, Test 2-18A.

Total Heat Flux Incident Energy Incident During Arc During Arc Phase Rack Tcap Energy Location (kW/m2) (kJ/m2) Comment No. No. (kJ/m2)

+/- 1.5 kW/m2 +/- 2.4 kJ/m2

+/- 2.4 kJ/m2 or +/- 2.9 % or +/- 5 %

or +/- 5 %

1 2 Top 35.1 53.7 116.8 This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 1 4 Mid-Right 35.8 65.1 129.6 1 6 Mid-Left 37.4 57.3 129.5 1 8 Bottom 48.4 93.9 146.2 2 11 Top 1.6 1.0 16.6 2 13 Mid-Right 0.4 0.8 15.6 2 15 Mid-Left 1.5 0.7 15.7 2 17 Bottom 0.3 14.2 EMI S/N 3 20 Top 4.5 8.3 96.8 3 22 Mid-Right 5.1 9.2 96.3 3 24 Mid-Left 3.6 6.8 93.7 3 26 Bottom 4.3 94.5 EMI S/N 4 29 Top 19.4 44.7 259.2 4 31 Mid-Right 19.0 39.0 261.4 4 33 Mid-Left 35.6 67.6 275.9 4 35 Bottom 40.4 48.2 224.2 5 38 Front 11.0 17.2 92.6 5 40 Center- 5.1 11.4 79.5 Right 5 42 Center- 16.3 84.0 EMI Left 5 44 Back 9.0 9.1 78.2 6 47 Front 2.6 4.5 58.9 6 49 Center- 0.6 2.7 55.2 Bottom 6 51 Center- 2.7 63.1 EMI S/N Top 6 53 Back 1.6 46.2 EMI S/N 109

3.8.1.3. Pressure Measurements The pressure profiles for the first two tenths of a second are shown in Fig. 70. After the initial pressure spike, the pressure rapidly decays to a relative steady state. The peak pressure is higher in the primary cable connection compartment as would be expected since this is the compartment where the arc is initiated. The maximum change in pressure in the main bus compartment is approximately 5 kPa (0.7 psi) above ambient at its peak. The maximum change in pressure in the breaker compartment is approximately 2 kPa (0.3 psi) above ambient. The 0 kPa to 207 kPa (0 psia to 30 psia) and 0 kPa to 345 kPa (0 psia to 50 psia) transducer recordings at a specific location were consistent.

This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Fig. 70. Pressure measurements from Test 2-18A (breaker compartment (left); Main bus [arcing compartment] - (right)). Measurement uncertainty +/- 3 percent.

3.8.1.4.Electrical measurements Test 2-18A used KEMA circuit S09 presented in Appendix C. Full-level circuit checks (calibration tests) were performed prior to the experiment to verify the experimental parameters were acceptable. For this experiment the calibration tests configured the power system to 0.616 kV, 13.5 kA symmetrical, and 35.6 kA peak. The KEMA report identifies this experiment as 190829-7005. Key experimental measurements are presented in Table 46. Plots of the electrical measurements are presented in Appendix B.

110

Table 46. Key measurement from Test 2-18A. Measurement uncertainty +/- 3 percent.

Phase Units A B C Applied voltage, phase-to-ground kVRMS 277 277 277 Applied voltage, phase-to-phase kVRMS 480 Making current kApeak -41.4 -38.5 46.2 Current, a.c. component, beginning kARMS 23.5 21.0 22.4 Current, a.c. component, middle kARMS 20.7 23.5 16.6 Current, a.c. component, end kARMS 15.9 18.2 12.5 Current, a.c. component, average kARMS 19.8 17.3 17.9 This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Current, a.c. component, three-phase average kARMS 18.3 Duration s 2.02 2.02 2.02 Arc Energy MJ 17.23 3.9. Test 2-18B - 600 V, 25 kA, 8 s duration, main bus, supply section Test 2-18A was performed on August 29, 2019 at 3:07 PM eastern daylight time (EDT). The temperature was approximately 28 °C (82 °F), approximately 34 percent relative humidity and approximately 101.3 kPa of pressure. The weather was fair with a 21 km/h (13 mi/h) wind out of the west.

The switchgear used in Tests 2-18A was used again in this experiment. The enclosure breach opening that occurred in Test 2-18A was covered by a piece of sheet metal. The gear was tested for sufficient insulation resistance between phases and found to be functional. The arcing wire was located around the vertical main bus work at the bottom of the supply breaker vertical section as shown in Fig. 71. All three phases were shorted with the shorting wire. Ground plates were installed near the top of the vertical main bus. The plate was approximately 6.4 cm (2.5 in) above the top of the vertical main bus. Switchgear enclosure was connected to neutral. Generator neutral was tied to ground via impedance.

111

This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Fig. 71. Shorting Wire Location Test 2-18B (Phases left-to-right: A-B-C) (top left); grounding plate (top right); illustration of shorting wire (red) and grounding plate (blue) locations elevation view (bottom left) and plan view (bottom right).

3.9.1. Observations Observations documented below are based on review of video and thermal imaging that was taken during the experiment. The observations are provided in Table 47 and include an approximate time reference. Corresponding images are provided in Fig. 72 and Fig. 73.

The arc did not sustain for the expected 8.0 s duration. The final arc extinguished at 8 310 ms.

112

Table 47. Observations from Test 2-18B.

Time (ms) Observation 0 Initial light observed in bottom rear louver Particle ejecta reaches rear instrumentation rack and observed in upper portion 200 of switchgear Arcing observed in upper portion of switchgear. Particle ejecta reaches first 500 instrumentation rack above enclosure This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 750 Particle ejecta reaches second instrumentation rack above enclosure 900 Arcing observed in lower portion of switchgear 1 568 Particle ejecta exceeds instrumentation rack to left side of load vertical section 4 003 Arcing observed in upper portion of switchgear 4 671 Arcing observed in lower portion of switchgear Particle eject from lower portion and larger hot gases (combustion) occurring in 5 105 upper region Arcing occurring in lower region of enclosure and color change indicating arc is 5 488 occurring near enclosure breach 8 341 Post-experiment particle ejecta and combustion 39 739 Fire continues to burn in lower portion of cabinet 732 700 NIST data acquisition ends 113

This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Fig. 72. Sequence of Images from Test 2-18B up to 4.671 s (image time stamps are in seconds).

114

This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Fig. 73. Sequence of images from Test 2-18B from 4.671 s (image time stamps are in seconds).

Photographs of the enclosure following the experiment are presented in Fig. 74 and Fig. 75. The enclosure did experience small breaches on the incoming (supply) side of the switchgear. There were no instruments located in this area due to the limited room and required separation distances by the incoming laboratory power conductors.

115

This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Fig. 74. Enclosure Post-Test 2-18B. load section (left), supply section (right)).

Fig. 75. Post-experiment image of enclosure. (load side (left), supply side (right)).

116

This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Fig. 76. Failure of KEMA cable connection observed as arcing occurring in Cell 8 (non-test cell).

3.9.1.1. Measurements Measurements made during Test 2-18B are presented below. These measurements include:

• Thermal o Heat flux - Plate Thermometers o Incident energy - ASTM Slug Calorimeter o Heat flux, incident energy - Tcap Slug Calorimeter

• Pressure o Internal pressure

• Electrical 3.9.1.2.Thermal Measurements Thermal measurements from the active instruments are reported below. These include PT measurements (Table 48), ASTM Slug Calorimeter measurements (Table 49), and Tcap slug measurements (Table 50). The maximum reading is identified with bold text. For some sensors, the EMI interfered with the thermal measurement. These are listed as -- and noted with EMI.

For some measurements, the EMI magnitude was of the same order as the signal. These are listed as -- and noted with EMI S/N.

The thermal exposures measured over the top of the switchgear (Instrument Rack 4) were greater than the preceding experiments in this report. This was due to the arc duration (approximately 2 s) and the heat and combustion products exiting from the vents at the top of the electrical enclosure from an ensuing fire in the enclosure.

117

Table 48. Summary of plate thermometer measurements Test 2-18B.

Max Heat Flux Average Heat Flux During Rack Plate Location (kW/m2) Arc (kW/m2)

No. No.

+/- 1 kW/m2 or +/- 5 % +/- 1 kW/m2 or +/- 5 %

1 1 Top 175 56 1 3 Mid-Right 128 31 1 5 Mid-Center 261 52 This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 1 7 Mid-Left 286 51 1 9 Bottom 305 61 2 10 Top 46 7 2 12 Mid-Right 14 3 2 14 Mid-Center 13 2 2 16 Mid-Left 14 3 2 18 Bottom 27 1 3 19 Top 153 26 3 21 Mid-Right 54 16 3 23 Mid-Center 67 12 3 25 Mid-Left 38 9 3 27 Bottom 29 7 4 28 Top 185 34 4 30 Mid-Right 280. 81 4 32 Mid-Center 320. 91 4 34 Mid-Left 390. 81 4 36 Bottom 357 89 5 37 Front 68 17 5 39 Center-Right 99 23 5 41 Center-Mid 195 29 5 43 Center-Left 150. 23 5 45 Back 208. 36 6 46 Front 83 13 6 48 Center-Bottom 23 5 6 50 Center-Mid 36 6 6 52 Center-Top 55 6 6 54 Back 23 3 118

Table 49. Summary of ASTM slug calorimeter measurements, Test 2-18B.

Incident Energy Time to Max Rack ASTM No. Location (kJ/m2) +/- 18kJ/m2 Temperature (s) +/-

No.

or +/- 4 % 3%

1 A Top 366 10 1 B Bottom 453 9 2 C Top 32 14 2 D Bottom 24 1040 3 E Top 187 512 This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 3 F Bottom 200 611 4 G Rear 670 13 4 H Front 962 12 5 I Rear 245 16 5 J Front 290 13 6 K Rear 178 322 6 L Front 177 522 119

Table 50. Summary of Tcap slug measurement, Test 2-18B.

Incident Total Heat Flux Energy During Incident During Arc Rack Tcap Arc Phase Energy Location (kW/m2) Comment No. No. (kJ/m2) (kJ/m2)

+/- 1.5 kW/m2

+/- 2.4 kJ/m2 +/- 2.4 kJ/m2 or +/- 2.9 %

or +/- 5 % or +/- 5 %

1 2 Top 78.7 429.8 584.0 This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 1 4 Mid-Right 60.9 372.9 527.1 1 6 Mid-Left 86.7 450.1 604.1 1 8 Bottom 73.9 429.9 577.8 2 11 Top 4.8 26.0 133.1 2 13 Mid-Right 3.2 17.6 110.6 2 15 Mid-Left 2.0 16.3 114.8 2 17 Bottom 1.8 10.3 100.5 3 20 Top 19.9 115.9 806.1 3 22 Mid-Right 18.4 110.8 859.2 3 24 Mid-Left 14.7 88.4 811.7 3 26 Bottom 12.3 65.2 856.7 4 29 Top 97.5 535.8 1648.0 4 31 Mid-Right 118.9 625.7 1576.6 4 33 Mid-Left 123.8 683.7 1788.7 4 35 Bottom 125.9 754.2 1513.1 5 38 Front 36.8 191.4 807.4 5 40 Center- 34.7 193.8 675.5 Right 5 42 Center-Left 41.8 205.6 708.9 5 44 Back 45.7 201.1 648.3 6 47 Front 50.9 750.5 EMI S/N 6 49 Center- 40.1 773.9 EMI S/N Bottom 6 51 Center-Top 5.2 39.8 805.9 6 53 Back 28.7 726.5 EMI S/N 120

3.9.1.3.Pressure Measurements The pressure profiles for the first two tenths of a second are shown in Fig. 77. After the initial pressure spike, the pressure rapidly decays to a relative steady state. The peak pressure is higher in the primary cable connection compartment as would be expected since this is the compartment where the arc is initiated. The maximum change in pressure in the main bus compartment is approximately 7 kPa (1.0 psi) above ambient at its peak. The maximum change in pressure in the breaker compartment is approximately 3 kPa (0.4 psi) above ambient. The 0 kPa to 207 kPa (0 psia to 30 psia) and 0 kPa to 345 kPa (0 psia to 50 psia) transducer recordings at a specific location were consistent.

This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Fig. 77. Pressure measurements from Test 2-18B (breaker compartment (left); Main bus [arcing compartment] - (right)). Measurement uncertainty +/- 3 percent.

3.9.1.4. Electrical measurements Test 2-18B used KEMA circuit S08 presented in Appendix C. Full-level circuit checks (calibration tests) were performed prior to the experiment to verify the experimental parameters were acceptable. For this experiment the calibration tests configured the power system to 0.616 kV, 25 kA symmetrical, and 63.3 kA peak. The KEMA report identifies this experiment as 190829-7006. Key experimental measurements are presented in Table 51. Plots of the electrical measurements are presented in Appendix B.

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Table 51. Key measurement from Test 2-18B. Measurement uncertainty +/- 3 percent.

Phase Units A B C Applied voltage, phase-to-ground kVRMS 357 357 357 Applied voltage, phase-to-phase kVRMS 618 Making current kApeak 35.4 -38.8 -32.4 Current, a.c. component, beginning kARMS 22.6 20.9 22.0 Current, a.c. component, middle kARMS 25.8 23.6 21.9 Current, a.c. component, end kARMS 15.6 22.2 24.3 Current, a.c. component, average kARMS 21.1 20.0 19.6 This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Current, a.c. component, three-phase average kARMS 20.2 Duration s 8.3 8.3 8.3 Arc Energy MJ 72.76 122

Summary and Conclusion This section provides a brief summary and conclusions made from the series of experiments documented in this report.

4.1. Summary A series of nine (9) individual arcing fault experiments on two separate switchgear units were performed. Each experiment consisted of a three-phase arcing fault initiated and sustained on This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 aluminum or copper electrodes within the low-voltage metal enclosed switchgear. Two experiments were initiated on the copper bus stabs; one experiment in the main bus compartment (Test 2-13D) and the other in the breaker cubicle (Test 2-13E). Post-experiment evaluation of Test 2-13D indicated that the arc migrated to the aluminum portion of the main bus. In Test 2-13E the arc was sustained on the copper portion of the gear without involving aluminum components.

All other experiments were initiated on the aluminum main bus. The magnitude of the arc current and duration was varied at a nominal system voltage of either 480 V or 600 V. Electrical parameters are summarized in Table 52. Numerous measurements were made to characterize the environment surrounding the switchgear, including external heat flux, external incident energy, electric field strength, air conductivity, optical emission spectrum, and internal pressure. A summary of the thermal measurements is provided in Table 53. Photometric equipment was deployed to capture the event using a combination of devices to characterize the thermal environment and event timing.

Table 52. Experiment Summary.

Nominal Test Current Arc Duration Energy Voltage (kV) Arc Location No. (kA) +/- 3 % (sec) +/- 3 % (MJ) +/- 3 %

+/-3%

2-13A 0.480 9 800 0.950 1.44 Main bus - upper 2-13B 0.600 9 973 0.399 1.38 Main bus - upper 2-13C 0.600 11 650 0.413 1.67 Main bus - upper 2-13D 0.600 9 266 0.926 4.21 Main bus - upper Breaker cubicle 2-13E 0.600 10 388 2.060 9.64 (copper) 2-13F 0.480 9 733 1.550 5.44 Main bus - lower 2-13G 0.600 10 707 2.020 10.40 Main bus - lower 2-18A 0.480 19 146 2.020 17.23 Main bus - lower 2-18B 0.600 19 349 8.310 72.76 Main bus - lower 123

Table 53. Summary of maximum incident energy measurements.

Bar Electrica ASTM (Copper) Tcap (Tungsten)

Materia Experiment l Energy Slug Slug l

1. Rack Distance Max. Total Max. Total Location (m) Incident Energy Incident Energy (MJ)

Al Cu (MJ/m2) (MJ/m2)

+/-3%

+/- 0.018 MJ/m2 +/- 0.002 MJ/m2 or +/- 4 % or +/- 5 %

Sides 0.91 No Data 0.013 This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 2-13A X 1.44 Above 0.91 No Data 0.018 Above 1.82 No Data 0.007 Sides 0.91 0.001 0.013 2-13B X 1.38 Above 0.91 0.006 0.020 Above 1.82 0.004 0.005 Sides 0.91 0.005 0.026 2-13C X 1.67 Above 0.91 0.009 0.030 Above 1.82 0.004 0.004 Sides 0.91 0.016 0.058 2-13D X 4.21 Above 0.91 0.022 0.071 Above 1.82 0.011 0.025 Sides 0.91 0.017 0.045 2-13E X 9.64 Above 0.91 0.090 0.263 Above 1.82 0.025 0.057 Sides 0.91 0.061 0.087 2-13F X 5.44 Above 0.91 0.009 0.022 Above 1.82 0.006 0.012 Sides 0.91 0.110 0.141 2-13G X 10.40 Above 0.91 0.030 0.107 Above 1.82 0.011 0.032 Sides 0.91 0.083 0.146 2-18A X 17.23 Above 0.91 0.092 0.276 Above 1.82 0.029 0.093 Sides 0.91 0.453 0.859 2-18B X 72.76 Above 0.91 0.962 1.789 Above 1.82 0.290 0.807 124

4.2. Conclusions This series of experiments provides valuable information related to the characteristics of the electrical arc and potential hazards, including:

• Low-voltage arc faults were difficult to sustain in the configuration studied.

• Arc migration from initiation point was evident in several of the experiments and consistent with observations from Phase 1 Testing [2]. The inability to sustain the arc in one location reduces the possibility of breaching the enclosure and exposing external targets to HEAF-generated incident energy.

This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197

• Sustaining an arc on copper was easier even with larger phase-to-phase separation than experiments performed on the aluminum bus. Location of the arc and internal combustible materials resulted in an ensuing fire which required manual intervention to extinguish.

• Pressure increases within the enclosure appeared to be minimal and didnt cause in the enclosure panels to deform or doors to open.

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Acknowledgments Funding for this work was provided by the U.S. Nuclear Regulatory Commission, Office of Research. This report was developed jointly between the National Institute of Standards and Technology (NIST), Sandia National Laboratories, and the U.S. Nuclear Regulatory Commission.

This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 126

References

[1] OECD Fire Project - Topical Report No. 1, Analysis of High Energy Arcing Faults (HEAF) Fire Events, Nuclear Energy Agency Committee on the Safety of Nuclear Installations, Organization for Economic Cooperation and Development, June 2013.

[2] NEA HEAF Project - TOPICAL REPORT No. 1, Experimental Results from the International High Energy Arcing Fault (HEAF) Research Program - Phase 1 Testing 2014 to 2016, Nuclear Energy Agency Committee on The Safety of Nuclear Installations, 2017

[3] NRC Information Notice 2017-04: High Energy Arcing Faults in Electrical Equipment Containing Aluminum Components, US NRC, Washington, DC, August 2017.

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[4] EPRI/NRC-RES Fire PRA Methodology for Nuclear Power Facilities, Volume 2: Detailed Methodology. Electric Power Research Institute (EPRI), Palo Alto, CA, and U.S. Nuclear Regulatory Commission, Office of Nuclear Regulatory Research (RES), Rockville, MD:

2005, EPRI TR-1011989 and NUREG/CR-6850.

[5] Fire Probabilistic Risk Assessment Methods Enhancements: Supplement 1 to NUREG/CR-6850 and EPRI 1011989, EPRI, Palo Alto, CA, and NRC, Washington, DC.: December 2009.

[6] Memorandum from Mark Henry Salley, to Thomas H. Boyce, Regarding submittal of possible generic issue concerning the damage caused by high energy arc faults in electrical equipment containing aluminum components, ADAMS Accession No. ML16126A096, May 2016.

[7] Memorandum from Joseph Giitter to Michael F. Weber, regarding Results of Generic Issue Review Panel Screening Evaluation for Proposed Generic Issue PRE-GI-018, High Energy Arcing Faults involving Aluminum, ADAMS Accession No. ML16349A027, July 15, 2017.

[8] Memorandum from Michael Franovich and Michael Cheok to Raymond V. Furstenau, regarding Assessment Plan for Pre-GI-018, Proposed Generic Issue on High Energy Arc Faults Involving Aluminum, ADAMS Accession No. ML18172A189, August 22, 2018.

[9] An International Phenomena Identification and Ranking Table (PIRT) Expert Elicitation Exercise for High Energy Arcing Faults (HEAFs), US NRC, Washington, DC, NUREG-2218, January 2018.

[10] NRC RIL 2021-10, NIST TN 2188, SNL SAND2021-12049 R, Report on High Energy Arcing Fault Experiments, Experimental Results from Medium Voltage Electrical Enclosures, U.S. Nuclear Regulatory Commission, Washington, DC, National Institute of Standards and Technology, Gaithersburg, MD, Sandia National Laboratories, Albuquerque, NM, November 2021.

[11] Tambakuchi, A., et. al., NRC HEAF Tests, Imaging and Measurement Methodology Report, SAND2021-12086 R, Sandia National Laboratories, September 2018.

[12] Lafarge, T. and Possolo, A, "The NIST Uncertainty Machine," NCLSI Measure J. Meas.

Sci., Vol. 10, No. 3, pp.20-27, September 2015.

[13] Putorti, A., Melly, M., Bareham, S., and Praydis Jr., J., Characterizing the Thermal Effects of High Energy Arc Faults. 23rd International Conference on Structural Mechanics in Reactor Technology (SMiRT 23) - 14th International Post-Conference Seminar on FIRE SAFETY IN NUCLEAR POWER PLANTS AND INSTALLATIONS, Salford, UK, August 17-18, 2015, http://www.grs.de/en/publications/grs-a-3845.

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[14] Ingason, H. and Wickstrom, U., "Measuring incident radiant heat flux using the plate thermometer," Fire Safety Journal, Vol. 42, No. 2, 2007, pp. 161-166.

[15] Taylor, B.N. and Kuyatt, C.E., "Guidelines for evaluating and expressing the uncertainty of NIST measurement results," NIST Technical Note 1297, National Institute of Standards and Technology, Gaithersburg, MD, USA, 1994.

[16] Joint Committee for Guides in Metrology. Evaluation of measurement data - Guide to the expression of uncertainty in measurement, Svres, France: International Bureau of Weights and Measures (BIPM), URL www.bipm.org/en/publications/guides/gum.html, BIPM, IEC, IFCC, ILAC, ISO, IUPAC, IUPAP and OIML, JCGM 100:2008, GUM 1995 with minor corrections (2008).

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[17] Joint Committee for Guides in Metrology. International vocabulary of metrology - Basic and general concepts and associated terms (VIM), Svres, France: International Bureau of Weights and Measures (BIPM), 3rd ed., URL www.bipm.org/en/publications/guides/vim.html, BIPM, IEC, IFCC, ILAC, ISO, IUPAC, IUPAP and OIML, JCGM 200:2012 (2008 version with minor corrections) (2012).

[18] ASTM (1993), Manual on the Use of Thermocouples in Temperature Measurement, ASTM Manual Series: MNL12, Revision of Special Publication (STP) 470B, 4th ed., ASTM International, West Conshohocken, PA, 1993, United States.

[19] McGrattan, K., Hostikka, S., McDermott, R., Floyd, J., Weinschenk, C., Overholt, K., Fire Dynamics Simulator, Technical Reference Guide. National Institute of Standards and Technology, Gaithersburg, MD, USA, and VTT Technical Research Centre of Finland, Espoo, Finland, sixth edition, September 2013. Vol. 1: Mathematical Model; Vol. 2:

Verification Guide; Vol. 3: Validation Guide; Vol. 4: Configuration Management Plan.

[20] ASTM Standard F1959 / F1959M-14, 2014, "Standard Test Method for Determining the Arc Rating of Materials for Clothing," ASTM International, West Conshohocken, PA, 2014.

[21] ASTM Standard E457-08, "Standard Test Method for Measuring Heat-Transfer Rate Using a Thermal Capacitance (Slug) Calorimeter," ASTM International, West Conshohocken, PA, 2008.

[22] Tektronix Mixed Domain Oscilloscopes, MDO4000C Series Datasheet, Tektronix, Beaverton, OR, https://www.tek.com site accessed November 2021.

[23] NRC RIL 2021-18, NIST TN 2198, SAND2021-16075 R, Report on High Energy Arcing Fault Experiments, Experimental Results from Open Box Enclosures, U.S. Nuclear Regulatory Commission, Washington, DC, National Institute of Standards and Technology, Gaithersburg, MD, Sandia National Laboratories, Albuquerque, NM, December 2021.

[24] Taylor, G., et. al., NUREG/CP-0311, Proceedings of the Information Sharing Workshop on High Energy Arcing Fault (HEAF), U.S. Nuclear Regulatory Commission, Rockville, MD, July 2019.

[25] NUREG/CR-6931, SAND2007-600/V2, Vol. 2, Nowlen, S.P., Wyant, F.J., Cable Response to Live Fire (CAROLFIRE), Vol 2.: Cable Fire Response Data for Fire Model Improvement, U.S. Nuclear Regulatory Commission, Washington, DC, Sandia National Laboratories, Albuquerque, NM, 2008.

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Appendix A: Engineering Drawings This appendix provides detailed drawings and information on the test facility, test object, and instrumentation.

A.1 Experimental Facility Drawings of the testing facility are presented in Fig. 78 through Fig. 80.

This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Fig. 78. Isometric drawing of Test Cell #7.

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This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Fig. 79. Plan view of Test Cell #7. Low-voltage power connections located on right side of drawing.

130

This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Fig. 80. Elevation view of Test Cell #7. Low-voltage power connections located on right side of drawing.

131

132 Support Drawings A.2 This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197

Fig. 81. Drawing KPT-MB-4657, ASTM Calorimeter Assembly.

133 This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197

Fig. 82. Drawing KPT-MA-4599, ASTM Calorimeter Cup.

134 This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197

Fig. 83. Isometric drawings of LV metal enclosed indoor switchgear.

135 This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197

Fig. 84. Plan and elevation drawings of LV metal enclosed indoor switchgear.

246 cm 234 cm 136 171 cm 108 cm This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197

Fig. 85. Drawing of interior layout of LV metal enclosed indoor switchgear.

137 This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197

Appendix B: Electrical Measurement This appendix presents plots of the electrical measurements made during each experiment.

This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 138

Experiment 2-13A, 480 V, 13.5 kA, 2 s, main bus top, load section The voltage and current profile for the entire duration of the experiment is shown in Fig. 86. The transient region for current phases is presented in Fig. 87. Energy and power profiles are presented in Fig. 88.

This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Fig. 86. Voltage and Current Profile during Test 2-13A. Measurement uncertainty +/- 3 percent.

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This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Fig. 87. Transient current profiles for Test 2-13A. Measurement uncertainty +/- 3 percent.

Fig. 88. Power and Energy for Test 2-13A. Measurement uncertainty +/- 3 percent.

140

Experiment 2-13B, 600 V, 13.5 kA, 2 s, main bus top, load section The voltage and current profile for the entire duration of the experiment is shown in Fig. 89. The transient region for current phases is presented in Fig. 90. Energy and power profiles are presented in Fig. 91.

This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Fig. 89. Voltage and Current Profile during Test 2-13B. Measurement uncertainty +/- 3 percent.

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This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Fig. 90. Transient current profiles for Test 2-13B. Measurement uncertainty +/- 3 percent.

Fig. 91. Power and Energy for Test 2-13B. Measurement uncertainty +/- 3 percent.

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Experiment 2-13C, 600 V, 13.5 kA, 2 s, main bus top load section The voltage and current profile for the entire duration of the experiment is shown in Fig. 92. The transient region for current phases is presented in Fig. 93. Energy and power profiles are presented in Fig. 94.

This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Fig. 92. Voltage and Current Profile during Test 2-13C. Measurement uncertainty +/- 3 percent.

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This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Fig. 93. Transient current profiles for Test 2-13C. Measurement uncertainty +/- 3 percent.

Fig. 94. Power and Energy for Test 2-13C. Measurement uncertainty +/- 3 percent.

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Experiment 2-13D, 600 V, 13.5 kA, 2 s, breaker stabs (copper), top load section The voltage and current profile for the entire duration of the experiment is shown in Fig. 95. The transient region for current phases is presented in Fig. 96. Energy and power profiles are presented in Fig. 97.

This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Fig. 95. Voltage and Current Profile during Test 2-13D. Measurement uncertainty +/- 3 percent.

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This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Fig. 96. Transient current profiles for Test 2-13D. Measurement uncertainty +/- 3 percent.

Fig. 97. Power and Energy for Test 2-13D. Measurement uncertainty +/- 3 percent.

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Experiment 2-13E, 600 V, 13.5 kA, 2 s, breaker stabs (copper) middle breaker cubicle The voltage and current profile for the entire duration of the experiment is shown in Fig. 98. The transient region for current phases is presented in Fig. 99. Energy and power profiles are presented in Fig. 100.

This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Fig. 98. Voltage and Current Profile during Test 2-13E. Measurement uncertainty +/- 3 percent.

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This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Fig. 99. Transient current profiles for Test 2-13E. Measurement uncertainty +/- 3 percent.

Fig. 100. Power and Energy for Test 2-13E. Measurement uncertainty +/- 3 percent.

148

Experiment 2-13F, 480 V, 13.5 kA, 2 s main bus, load section The voltage and current profile for the entire duration of the experiment is shown in Fig. 101. The transient region for current phases is presented in Fig. 102. Energy and power profiles are presented in Fig. 103.

This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Fig. 101. Voltage and Current Profile during Test 2-13F. Measurement uncertainty +/- 3 percent.

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This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Fig. 102. Transient current profiles for Test 2-13F. Measurement uncertainty +/- 3 percent.

Fig. 103. Power and Energy for Test 2-13F. Measurement uncertainty +/- 3 percent.

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Experiment 2-13G, 600 V, 13.5 kA, 2 s, main bus, supply section The voltage and current profile for the entire duration of the experiment is shown in Fig. 104. The transient region for current phases is presented in Fig. 105. Energy and power profiles are presented in Fig. 106.

This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Fig. 104. Voltage and Current Profile during Test 2-13G. Measurement uncertainty +/- 3 percent.

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This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Fig. 105. Transient current profiles for Test 2-13G. Measurement uncertainty +/- 3 percent.

Fig. 106. Power and Energy for Test 2-13G. Measurement uncertainty +/- 3 percent.

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Experiment 2-18A, 480 V, 25 kA, 8 s, main bus, load section The voltage and current profile for the entire duration of the experiment is shown in Fig. 107. The transient region for current phases is presented in Fig. 108. Energy and power profiles are presented in Fig. 109.

This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Fig. 107. Voltage and Current Profile during Test 2-18A. Measurement uncertainty +/- 3 percent.

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This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Fig. 108. Transient current profiles for Test 2-18A. Measurement uncertainty +/- 3 percent.

Fig. 109. Power and Energy for Test 2-18A. Measurement uncertainty +/- 3 percent.

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Experiment 2-18B, 600 V, 25 kA, 8 s, main bus, supply section The voltage and current profile for the entire duration of the experiment is shown in Fig. 110. The transient region for current phases is presented in Fig. 111. Energy and power profiles are presented in Fig. 112.

This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Fig. 110. Voltage and Current Profile during Test 2-18B. Measurement uncertainty +/- 3 percent.

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This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197 Fig. 111. Transient current profiles for Test 2-18B. Measurement uncertainty +/- 3 percent.

Fig. 112. Power and Energy for Test 2-18B. Measurement uncertainty +/- 3 percent.

156

This appendix provides a copy of KEMA test report.

157 Appendix C: KEMA Test Report This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2197

KEMA TEST REPORT 24512323 Object Medium & Low Voltage Switchgear Type High Energy Arc Fault (HEAF) Serial No. N/A Various V, rms - Various kA, rms - 60 Hz Client U.S. Nuclear Regulatory Commission Washington, DC, USA Tested by KEMA-Powertest LLC, 4379 County Line Road Chalfont, PA 18914, USA Date of tests 22, 23, 26, 27, 28, 29 and 30 August 2019 and 16, 17 and 18 September 2019 Test specification The arc fault tests have been carried out in accordance with client's instructions.

This report applies only to the object tested. The responsibility for conformity of any object having the same type references as that tested rests with the Manufacturer.

This report consists of 356 pages in total.

KEMA Powertest, LLC Frank Cielo Head of Department, Operations KEMA Laboratories Chalfont, February 11, 2020 DATE Copyright: Only integral reproduction of this report is permitted without written permission from DNV GL. Electronic copies as PDF or scan of this report may be available and have the status for information only. The original Protected PDF version of the report is the only valid version.

KEMA Laboratories 24512323 INFORMATION SHEET 1 KEMA Type Test Certificate A KEMA Type Test Certificate contains a record of a series of (type) tests carried out in accordance with a recognized standard. The object tested has fulfilled the requirements of this standard and the relevant ratings assigned by the manufacturer are endorsed by DNV GL. In addition, the objects technical drawings have been verified and the condition of the object after the tests is assessed and recorded. The Certificate contains the essential drawings and a description of the object tested. A KEMA Type Test Certificate signifies that the object meets all the requirements of the named subclauses of the standard. It can be identified by gold-embossed lettering on the cover and a gold seal on its front sheet.

The Certificate is applicable to the object tested only. DNV GL is responsible for the validity and the contents of the Certificate. The responsibility for conformity of any object having the same type references as the one tested rests with the manufacturer.

Detailed rules on types of certification are given in DNV GLs Certification procedure applicable to KEMA Laboratories.

2 KEMA Report of Performance A KEMA Report of Performance is issued when an object has successfully completed and passed a subset (but not all) of test programmes in accordance with a recognized standard. In addition, the objects technical drawings have been verified and the condition of the object after the tests is assessed and recorded. The report is applicable to the object tested only. A KEMA Report of Performance signifies that the object meets the requirements of the named subclauses of the standard. It can be identified by silver-embossed lettering on the cover and a silver seal on its front sheet.

The sentence on the front sheet of a KEMA Report of Performance will state that the tests have been carried out in accordance with The object has complied with the relevant requirements.

3 KEMA Test Report A KEMA Test Report is issued in all other cases. Reasons for issuing a KEMA Test Report could be:

Tests were performed according to the clients instructions.

Tests were performed only partially according to the standard.

No technical drawings were submitted for verification and/or no assessment of the condition of the object after the tests was performed.

The object failed one or more of the performed tests.

The KEMA Test Report can be identified by the grey-embossed lettering on the cover and grey seal on its front sheet.

In case the number of tests, the test procedure and the test parameters are based on a recognized standard and related to the ratings assigned by the manufacturer, the following sentence will appear on the front sheet. The tests have been carried out in accordance with the client's instructions. Test procedure and test parameters were based on ..... If the object does not pass the tests such behaviour will be mentioned on the front sheet. Verification of the drawings (if submitted) and assessment of the condition after the tests is only done on client's request.

When the tests, test procedure and/or test parameters are not in accordance with a recognized standard, the front sheet will state the tests have been carried out in accordance with clients instructions.

4 Official and uncontrolled test documents The official test documents of DNV GL are issued in bound form. Uncontrolled copies may be provided as a digital file for convenience of reproduction by the client. The copyright has to be respected at all times.

5 Accreditation of KEMA Laboratories The KEMA Laboratories of DNV GL are accredited in accordance with ISO/IEC 17025 by the respective national accreditation bodies. KEMA Laboratories Arnhem, the Netherlands, is accredited by RvA under nos. L020, L218, K006 and K009. KEMA Laboratories Chalfont, United States, is accredited by A2LA under no. 0553.01. KEMA Laboratories Prague, the Czech Republic, is accredited by CAI as testing laboratory no. 1035.

KEMA Laboratories 24512323 TABLE OF CONTENTS 1 Identification of the object tested ................................................................................ 9 1.1 Ratings/characteristics of the object tested 9 1.2 Description of the object tested 9 2 General Information ................................................................................................ 10 2.1 The tests were witnessed by 10 2.2 The tests were carried out under responsibility of 10 2.3 Accuracy of measurement 11 2.4 Notes 11 3 Legend .................................................................................................................. 12 4 Checking the prospective current ............................................................................... 13 4.1 Condition before test 13 4.2 Test results and oscillograms 14 5 Open Box Test # 1 (OB01(A)) - 1000 V, 1 kA .............................................................. 17 5.1 Condition before test 17 5.2 Test circuit S01 18 5.3 Test results and oscillograms 19 5.4 Condition / inspection after test 21 6 Open Box Test # 2 (OB01(B)) - 1000 V, 1 kA .............................................................. 22 6.1 Condition before test 22 6.2 Test circuit S01 23 6.3 Test results and oscillograms 24 6.4 Condition / inspection after test 26 7 Open Box Test # 3 (OB05) - 1000 V, 1 kA .................................................................. 27 7.1 Condition before test 27 7.2 Test circuit S01 28 7.3 Test results and oscillograms 29 7.4 Condition / inspection after test 31 8 Open Box Test # 4 (OB10) - 1000 V, 5 kA .................................................................. 32 8.1 Condition before test 32 8.2 Test circuit S02 33 8.3 Test results and oscillograms 34 8.4 Condition / inspection after test 36 9 Open Box Test # 5 (OB09) - 1000 V, 5 kA .................................................................. 37 9.1 Condition before test 37 9.2 Test circuit S02 38

KEMA Laboratories 24512323 9.3 Test results and oscillograms 39 9.4 Condition / inspection after test 41 10 Checking the prospective current ............................................................................... 42 10.1 Condition before test 42 10.2 Test results and oscillograms 43 11 Open Box Test # 6 (OB06) - 1000 V, 15 kA................................................................. 46 11.1 Condition before test 46 11.2 Test circuit S03 47 11.3 Test results and oscillograms 48 11.4 Condition / inspection after test 50 12 Open Box Test # 7 (OB07) - 1000 V, 15 kA................................................................ 51 12.1 Condition before test 51 12.2 Test circuit S03 52 12.3 Test results and oscillograms 53 12.4 Condition / inspection after test 55 13 Open Box Test # 8 (OB08) - 1000 V, 30 kA................................................................. 56 13.1 Condition before test 56 13.2 Test circuit S04 57 13.3 Test results and oscillograms 58 13.4 Condition / inspection after test 60 14 Open Box Test # 9 (OB11) - Single Phase Investigation ................................................ 61 14.1 Condition before test 61 14.2 Test circuit S05 62 14.3 Test results and oscillograms 63 14.4 Condition / inspection after test 65 15 Checking the prospective current ............................................................................... 66 15.1 Condition before test 66 15.2 Test results and oscillograms 67 16 Sample 2-13 (A) - 480 V, 13.5 kA ............................................................................. 70 16.1 Condition before test 70 16.2 Test circuit S06 71 16.3 Test results and oscillograms 72 16.4 Condition / inspection after test 74 17 Sample 2-13 (B) - 600 V, 13.5 kA ............................................................................. 75 17.1 Condition before test 75 17.2 Test circuit S07 76 17.3 Test results and oscillograms 77

KEMA Laboratories 24512323 17.4 Condition / inspection after test 79 18 Sample 2-13 (C) - 600 V, 13.5 kA ............................................................................. 80 18.1 Condition before test 80 18.2 Test circuit S07 81 18.3 Test results and oscillograms 82 18.4 Condition / inspection after test 84 19 Sample 2-13 (D) - 600 V, 13.5 kA ............................................................................. 85 19.1 Condition before test 85 19.2 Test circuit S07 86 19.3 Test results and oscillograms 87 19.4 Condition / inspection after test 89 20 Sample 2-13 (E) - 600 V, 13.5 kA.............................................................................. 90 20.1 Condition before test 90 20.2 Test circuit S07 91 20.3 Test results and oscillograms 92 20.4 Condition / inspection after test 94 21 Sample 2-13 (F) - 480 V, 13.5 kA .............................................................................. 95 21.1 Condition before test 95 21.2 Test circuit S06 96 21.3 Test results and oscillograms 97 21.4 Condition / inspection after test 99 22 Sample 2-13 (G) - 600 V, 13.5 kA ............................................................................100 22.1 Condition before test 100 22.2 Test circuit S07 101 22.3 Test results and oscillograms 102 22.4 Condition / inspection after test 104 23 Checking the prospective current ..............................................................................105 23.1 Condition before test 105 23.2 Test results and oscillograms 106 24 Sample 2-18 (A) - 480 V, 25 kA ...............................................................................111 24.1 Condition before test 111 24.2 Test circuit S09 112 24.3 Test results and oscillograms 113 24.4 Condition / inspection after test 115 25 Sample 2-18 (B) - 600 V, 25 kA ...............................................................................116 25.1 Condition before test 116 25.2 Test circuit S08 117

KEMA Laboratories 24512323 25.3 Test results and oscillograms 118 25.4 Condition / inspection after test 120 26 Open Box Test # 10 (OB02) - 1000 V, 15 kA ..............................................................121 26.1 Condition before test 121 26.2 Test circuit S03 122 26.3 Test results and oscillograms 123 26.4 Condition / inspection after test 125 27 Open Box Test # 11 (OB03) - 1000 V, 15 kA ..............................................................126 27.1 Condition before test 126 27.2 Test circuit S03 127 27.3 Test results and oscillograms 128 27.4 Condition / inspection after test 130 28 Open Box Test # 12 (OB04) - 1000 V, 30 kA ..............................................................131 28.1 Condition before test 131 28.2 Test circuit S04 132 28.3 Test results and oscillograms 133 28.4 Condition / inspection after test 135 29 Open Box Test # 13 (OB16) - Single Phase Investigation .............................................136 29.1 Condition before test 136 29.2 Test circuit S05 137 29.3 Test results and oscillograms 138 29.4 Condition / inspection after test 140 30 Open Box Test # 14 (OB12(A)) - Single Phase Investigation .........................................141 30.1 Condition before test 141 30.2 Test circuit S05 142 30.3 Test results and oscillograms 143 30.4 Condition / inspection after test 145 31 Open Box Test # 15 (OB15) - Single Phase Investigation .............................................146 31.1 Condition before test 146 31.2 Test circuit S05 147 31.3 Test results and oscillograms 148 31.4 Condition / inspection after test 150 32 Open Box Test # 16 (OB14) - Single Phase Investigation .............................................151 32.1 Condition before test 151 32.2 Test circuit S05 152 32.3 Test results and oscillograms 153 32.4 Condition / inspection after test 155

KEMA Laboratories 24512323 33 Open Box Test # 17 (OB12(B) & OB12(C)) - Single Phase Investigation .........................156 33.1 Condition before test 156 33.2 Test circuit S05 157 33.3 Test results and oscillograms 158 33.4 Condition / inspection after test 161 34 Open Box Test # 18 - 480 V, 13.5 kA ........................................................................162 34.1 Condition before test 162 34.2 Test circuit S06 163 34.3 Test results and oscillograms 164 34.4 Condition / inspection after test 166 35 Checking the prospective current ..............................................................................167 35.1 Condition before test 167 35.2 Test results and oscillograms 168 36 OBMV # 5 .............................................................................................................173 36.1 Condition before test 173 36.2 Test circuit S11 174 36.3 Test results and oscillograms 175 36.4 Condition / inspection after test 177 37 OBMV # 2 .............................................................................................................178 37.1 Condition before test 178 37.2 Test circuit S11 179 37.3 Test results and oscillograms 180 37.4 Condition / inspection after test 182 38 OBMV # 4 .............................................................................................................183 38.1 Condition before test 183 38.2 Test circuit S10 184 38.3 Test results and oscillograms 185 38.4 Condition / inspection after test 187 39 OBMV # 1 .............................................................................................................188 39.1 Condition before test 188 39.2 Test circuit S10 189 39.3 Test results and oscillograms 190 39.4 Condition / inspection after test 192 40 OBMV # 3 .............................................................................................................193 40.1 Condition before test 193 40.2 Test circuit S10 194 40.3 Test results and oscillograms 195

KEMA Laboratories 24512323 40.4 Condition / inspection after test 197 41 OBMV # 6 .............................................................................................................198 41.1 Condition before test 198 41.2 Test circuit S10 199 41.3 Test results and oscillograms 200 41.4 Condition / inspection after test 202 42 Attachments ..........................................................................................................203

1. Calorimeter Data Records [15 PAGES]

2. Instrumentation Information Sheets [2 PAGES]

3. Photographs (269) [135 PAGES]

End of Document [1 PAGE]

KEMA Laboratories 24512323 1 IDENTIFICATION OF THE OBJECT TESTED 1.1 Ratings/characteristics of the object tested Voltage Various V Number of phases 3 Frequency 60 Hz Short-circuit current Various kA 1.2 Description of the object tested Low and Medium Voltage Box Tests, High Energy Arcing Faults Low Voltage Switchgear, High Energy Arcing Faults

KEMA Laboratories 24512323 2 GENERAL INFORMATION 2.1 The tests were witnessed by Name Company Christopher Brown National Institute of Standards and Technology (NIST)

Michael Selepak Anthony Putorti Scott Bareham Andre Thompson Philip Deardorff Benny Lee BSI Electrical Contractors John Jones Montgomeryville, PA, USA Robert Taylor Jeff McKnight Byron Demostehnous Sandia National Laboratories Kenneth Armijo Albuquerque, NM, USA James Taylor Alvaro Augusto Cruz-Cabrera Chris Lafleur Raina Weaver Scott Sanborn Austin Glover Paul Clem Ray Martinez Caroline Winters Nick Melly U.S. Nuclear Regulatory Commission Kenneth Hamburger Washington, DC, USA Kenn Miller Gabriel Taylor Thomas Koshy Ken Fleischer Electric Power Research Institue Marko Randelovic 2.2 The tests were carried out under responsibility of Name Company Joe Duffy KEMA-Powertest LLC, Chalfont, PA, USA

KEMA Laboratories 24512323 2.3 Accuracy of measurement The guaranteed uncertainty in the figures mentioned, taking into account the total measuring system, is less than 3%, unless mentioned otherwise. Measurement uncertainty can be verified by reviewing the instrument calibration records. The instruments used are calibrated on a regular basis and are traceable to the National Institute of Standards and Technology.

2.4 Notes

KEMA Laboratories 24512323 3 LEGEND Phase indications If more than one phase is recorded on oscillogram, the phases are indicated by the digits 1, 2 and 3.

These phases 1, 2 and 3 correspond to the phase values in the columns of the accompanying table, respectively from left to right.

Explanation of the letter symbols and abbreviations on the oscillograms pu Per unit (the reference length of one unit is represented by the black bar on the oscillogram)

I1TO Current through test object I2TO Current through test object I3TO Current through test object Ineut Neutral current PT # 1 Pressure transducer # 1 PT # 2 Pressure transducer # 2 PT # 3 Pressure transducer # 3 PT # 4 Pressure transducer # 4 TRIG Trigger signal transient recorder U1TO Voltage across test object U2TO Voltage across test object U3TO Voltage across test object

KEMA Laboratories 24512323 4 CHECKING THE PROSPECTIVE CURRENT Standard and date Standard Clients instructions Test date 22 August 2019 4.1 Condition before test Shorting bar connected at station terminals directly prior to test device.

KEMA Laboratories 24512323 4.2 Test results and oscillograms Overview of test numbers 190822-7001, 7002 Remarks Prospective circuit parameters calibrated in this test duty:

190822-7001: 1000 V, 1040 A, 2860 A peak.

190822-7002: 1000 V, 5053 A, 14.9 kA peak.

KEMA Laboratories 24512323 Checking the prospective current Test number: 190822-7001 Phase A B C Current kApeak 2.13 2.23 -2.86 Current, a.c. component kARMS 1.04 1.04 1.04 Current, a.c. component, three-phase kARMS 1.04 average Duration, current s 0.176 0.176 0.175 Observations: No visible disturbance.

KEMA Laboratories 24512323 Checking the prospective current Test number: 190822-7002 Phase A B C Current kApeak 11.6 11.3 -14.9 Current, a.c. component kARMS 4.89 5.15 5.12 Current, a.c. component, three-phase kARMS 5.05 average Duration, current s 0.170 0.170 0.169 Observations: No visible disturbance.

KEMA Laboratories 24512323 5 OPEN BOX TEST # 1 (OB01(A)) - 1000 V, 1 KA Standard and date Standard Clients instructions Test date 22 August 2019 5.1 Condition before test Test device new. Arc to be initiated by #10 AWG stranded wire. Arc wire connected to 1/2" diameter copper rods. Test duration is 2 seconds.

KEMA Laboratories 24512323 5.2 Test circuit S01 MB XS ABUB MS TD G V N

V V

G = Generator ABUB = Aux. Breaker R = Resistance N = Neutral XFMR = Transformer C = Capacitance MB = Main Breaker TD = Test Device V = Voltage Measurement MS = Make Switch X = Inductance I = Current Measurement Supply Power MVA 1.801 Frequency Hz 60 Phase(s) 3 Voltage V 1000 Sym. Current kA 1.040 Peak current kA 2.86 Impedance 0.5551 Remarks: -

KEMA Laboratories 24512323 5.3 Test results and oscillograms Overview of test numbers 190822-7003 Remarks

KEMA Laboratories 24512323 Open Box Test # 1 (OB01) - 1000 V, 1 kA Test number: 190822-7003 Phase A B C Applied voltage, phase-to-ground VRMS 577 577 577 Applied voltage, phase-to-phase VRMS 999 Making current kApeak 2.14 2.26 -2.89 Current, a.c. component, beginning ARMS 1064 1061 1050 Current, a.c. component, middle ARMS 1052 1049 1039 Current, a.c. component, end ARMS 1119 1006 985 Current, a.c. component, average ARMS 1042 1048 1009 Current, a.c. component, three-phase ARMS 1033 average Duration s 2.01 2.01 2.01 Arc energy kJ 66.7 106 27.9 Observations: Emission of flames and gas observed. Arc wire took approximately 1.35 seconds to melt and initiate the arc.

KEMA Laboratories 24512323 5.4 Condition / inspection after test Box lightly damaged, another arc test can be performed with this sample.

KEMA Laboratories 24512323 6 OPEN BOX TEST # 2 (OB01(B)) - 1000 V, 1 KA Standard and date Standard Clients instructions Test date 22 August 2019 6.1 Condition before test Test device previously subjected to arc test at 1000 V, 1 kA. Arc to be initiated by #24 AWG wire. Arc wire connected to 1/2" diameter copper rods. Test duration is 2 seconds.

KEMA Laboratories 24512323 6.2 Test circuit S01 MB XS ABUB MS TD G V N

V V

G = Generator ABUB = Aux. Breaker R = Resistance N = Neutral XFMR = Transformer C = Capacitance MB = Main Breaker TD = Test Device V = Voltage Measurement MS = Make Switch X = Inductance I = Current Measurement Supply Power MVA 1.801 Frequency Hz 60 Phase(s) 3 Voltage V 1000 Sym. Current kA 1.040 Peak current kA 2.86 Impedance 0.5551 Remarks: -

KEMA Laboratories 24512323 6.3 Test results and oscillograms Overview of test numbers 190822-7004 Remarks

KEMA Laboratories 24512323 Open Box Test # 2 (OB01, re-test) - 1000 V, 1 kA Test number: 190822-7004 Phase A B C Applied voltage, phase-to-ground VRMS 577 577 577 Applied voltage, phase-to-phase VRMS 999 Making current kApeak 2.14 2.02 -2.63 Current, a.c. component, beginning ARMS 1056 1009 985 Current, a.c. component, middle ARMS 1124 1035 1015 Current, a.c. component, end ARMS 1128 1011 974 Current, a.c. component, average ARMS 1083 1030 985 Current, a.c. component, three-phase ARMS 1033 average Duration s 2.02 2.02 2.02 Arc energy kJ 248 289 199 Observations: Emission of flames and gas observed.

KEMA Laboratories 24512323 6.4 Condition / inspection after test Box slightly more damaged than previous arc test. End of copper conductors melted slightly.

KEMA Laboratories 24512323 7 OPEN BOX TEST # 3 (OB05) - 1000 V, 1 KA Standard and date Standard Clients instructions Test date 22 August 2019 7.1 Condition before test Test device previously subjected to two arc tests at 1000 V, 1 kA. Arc to be initiated by #24 AWG wire. Arc wire connected to 1/2" diameter aluminum rods. Test duration is 2 seconds.

KEMA Laboratories 24512323 7.2 Test circuit S01 MB XS ABUB MS TD G V N

V V

G = Generator ABUB = Aux. Breaker R = Resistance N = Neutral XFMR = Transformer C = Capacitance MB = Main Breaker TD = Test Device V = Voltage Measurement MS = Make Switch X = Inductance I = Current Measurement Supply Power MVA 1.801 Frequency Hz 60 Phase(s) 3 Voltage V 1000 Sym. Current kA 1.040 Peak current kA 2.86 Impedance 0.5551 Remarks: -

KEMA Laboratories 24512323 7.3 Test results and oscillograms Overview of test numbers 190822-7005 Remarks

KEMA Laboratories 24512323 Open Box Test # 3 (OB05) - 1000 V, 1 kA Test number: 190822-7005 Phase A B C Applied voltage, phase-to-ground VRMS 577 577 577 Applied voltage, phase-to-phase VRMS 999 Making current kApeak 2.12 1.91 -2.63 Current, a.c. component, beginning ARMS 1088 958 949 Current, a.c. component, middle ARMS 1173 1064 963 Current, a.c. component, end ARMS 1000 1075 943 Current, a.c. component, average ARMS 1080 1031 942 Current, a.c. component, three-phase ARMS 1018 average Duration s 2.01 2.01 2.01 Arc energy kJ 262 329 205 Observations: Emission of flames and gas observed.

KEMA Laboratories 24512323 7.4 Condition / inspection after test Box covered in ash, but still able to withstand another arc test. Aluminum rods discolored to a slightly white color.

KEMA Laboratories 24512323 8 OPEN BOX TEST # 4 (OB10) - 1000 V, 5 KA Standard and date Standard Clients instructions Test date 22 August 2019 8.1 Condition before test Test device previously subjected to three arc tests at 1000 V, 1 kA. Arc to be initiated by #24 AWG wire. Arc wire connected to 1/2" diameter aluminum rods. Test duration is 2 seconds.

KEMA Laboratories 24512323 8.2 Test circuit S02 MB XS ABUB MS TD G V N

V V

G = Generator ABUB = Aux. Breaker R = Resistance N = Neutral XFMR = Transformer C = Capacitance MB = Main Breaker TD = Test Device V = Voltage Measurement MS = Make Switch X = Inductance I = Current Measurement Supply Power MVA 8.75 Frequency Hz 60 Phase(s) 3 Voltage V 1000 Sym. Current kA 5.053 Peak current kA 14.9 Impedance 0.114 Remarks: -

KEMA Laboratories 24512323 8.3 Test results and oscillograms Overview of test numbers 190822-7006 Remarks

KEMA Laboratories 24512323 Open Box Test # 4 (OB10) - 1000 V, 5 kA Test number: 190822-7006 Phase A B C Applied voltage, phase-to-ground VRMS 577 577 577 Applied voltage, phase-to-phase VRMS 999 Making current kApeak 7.73 7.76 -8.47 Current, a.c. component, beginning ARMS 4812 4548 4309 Current, a.c. component, middle ARMS 5190 5297 4487 Current, a.c. component, end ARMS 5041 5559 4936 Current, a.c. component, average ARMS 5193 5081 4499 Current, a.c. component, three-phase ARMS 4924 average Duration s 2.00 2.00 2.00 Arc energy kJ 1190 1960 968 Observations: Emission of flames and gas observed.

KEMA Laboratories 24512323 8.4 Condition / inspection after test Interior and sides of the exterior of the box were heavily burned. Box will be replaced for next test.

KEMA Laboratories 24512323 9 OPEN BOX TEST # 5 (OB09) - 1000 V, 5 KA Standard and date Standard Clients instructions Test date 22 August 2019 9.1 Condition before test Test device new. Arc to be initiated by #24 AWG wire. Arc wire connected to 1/2" diameter copper rods. Test duration is 2 seconds.

KEMA Laboratories 24512323 9.2 Test circuit S02 MB XS ABUB MS TD G V N

V V

G = Generator ABUB = Aux. Breaker R = Resistance N = Neutral XFMR = Transformer C = Capacitance MB = Main Breaker TD = Test Device V = Voltage Measurement MS = Make Switch X = Inductance I = Current Measurement Supply Power MVA 8.75 Frequency Hz 60 Phase(s) 3 Voltage V 1000 Sym. Current kA 5.053 Peak current kA 14.9 Impedance 0.114 Remarks: -

KEMA Laboratories 24512323 9.3 Test results and oscillograms Overview of test numbers 190822-7007 Remarks

KEMA Laboratories 24512323 Open Box Test # 5 (OB09) - 1000 V, 5 kA Test number: 190822-7007 Phase A B C Applied voltage, phase-to-ground VRMS 577 577 577 Applied voltage, phase-to-phase VRMS 999 Making current kApeak 7.64 7.07 -8.32 Current, a.c. component, beginning ARMS 5011 3955 4100 Current, a.c. component, middle ARMS 5140 5170 4313 Current, a.c. component, end ARMS 5296 5113 4494 Current, a.c. component, average ARMS 5179 4869 4370 Current, a.c. component, three-phase ARMS 4806 average Duration s 2.01 2.01 2.01 Arc energy kJ 21.7 1401 819 Observations: Emission of flames and gas observed.

KEMA Laboratories 24512323 9.4 Condition / inspection after test Interior and sides of the exterior of the box were heavily burned. Box will be replaced for next test.

KEMA Laboratories 24512323 10 CHECKING THE PROSPECTIVE CURRENT Standard and date Standard Clients instructions Test date 23 August 2019 10.1 Condition before test Shorting bar connected at station terminals directly prior to test device.

KEMA Laboratories 24512323 10.2 Test results and oscillograms Overview of test numbers 190823-7001, 7002 Remarks Prospective circuit parameters calibrated in this test duty:

190823-7001: 1064 V, 30 kA, 79.1 kA peak.

190823-7002: 1009 V, 15 kA, 40.4 kA peak.

KEMA Laboratories 24512323 Checking the prospective current Test number: 190823-7001 Phase A B C Current kApeak 56.6 58.1 -74.6 Current, a.c. component kARMS 27.8 28.7 28.1 Current, a.c. component, three-phase kARMS 28.2 average Duration, current s 0.176 0.176 0.175 Observations: No visible disturbance.

KEMA Laboratories 24512323 Checking the prospective current Test number: 190823-7002 Phase A B C Current kApeak 29.7 31.3 -40.0 Current, a.c. component kARMS 14.6 15.1 14.9 Current, a.c. component, three-phase kARMS 14.9 average Duration, current s 0.177 0.177 0.176 Observations: No visible disturbance.

KEMA Laboratories 24512323 11 OPEN BOX TEST # 6 (OB06) - 1000 V, 15 KA Standard and date Standard Clients instructions Test date 23 August 2019 11.1 Condition before test Test device new. Arc to be initiated by #24 AWG wire. Arc wire connected to 1" diameter aluminum rods. Test duration is 2 seconds.

KEMA Laboratories 24512323 11.2 Test circuit S03 MB XS ABUB MS XP RP XFMR TD G V N

V V

G = Generator ABUB = Aux. Breaker R = Resistance N = Neutral XFMR = Transformer C = Capacitance MB = Main Breaker TD = Test Device V = Voltage Measurement MS = Make Switch X = Inductance I = Current Measurement Supply Power MVA 26.2 Frequency Hz 60 Phase(s) 3 Voltage V 1009 Sym. Current kA 15 Peak current kA 40.4 Impedance 0.014 Remarks: -

KEMA Laboratories 24512323 11.3 Test results and oscillograms Overview of test numbers 190823-7003 Remarks

KEMA Laboratories 24512323 Open Box Test # 6 (OB06) - 1000 V, 15 kA Test number: 190823-7003 Phase A B C Applied voltage, phase-to-ground VRMS 583 583 583 Applied voltage, phase-to-phase VRMS 1010 Making current kApeak -21.1 19.6 20.6 Current, a.c. component, beginning kARMS 14.1 9.95 14.5 Current, a.c. component, middle kARMS 12.8 12.6 11.4 Current, a.c. component, end kARMS 11.3 9.74 10.1 Current, a.c. component, average kARMS 13.1 12.1 12.1 Current, a.c. component, three-phase kARMS 12.4 average Duration s 2.02 2.02 2.02 Arc energy kJ 7434 483 4674 Observations: Emission of flames and gas observed.

KEMA Laboratories 24512323 11.4 Condition / inspection after test Bottom of box burned completely through. Sides of box heavily burned, but not burned through completely.

KEMA Laboratories 24512323 12 OPEN BOX TEST # 7 (OB07) - 1000 V, 15 KA Standard and date Standard Clients instructions Test date 23 August 2019 12.1 Condition before test Test device new. Arc to be initiated by #24 AWG wire. Arc wire connected to 1" diameter aluminum rods. Test duration is 1.5 seconds.

KEMA Laboratories 24512323 12.2 Test circuit S03 MB XS ABUB MS XP RP XFMR TD G V N

V V

G = Generator ABUB = Aux. Breaker R = Resistance N = Neutral XFMR = Transformer C = Capacitance MB = Main Breaker TD = Test Device V = Voltage Measurement MS = Make Switch X = Inductance I = Current Measurement Supply Power MVA 26.2 Frequency Hz 60 Phase(s) 3 Voltage V 1009 Sym. Current kA 15 Peak current kA 40.4 Impedance 0.014 Remarks: -

KEMA Laboratories 24512323 12.3 Test results and oscillograms Overview of test numbers 190823-7004 Remarks

KEMA Laboratories 24512323 Open Box Test # 7 - 1000 V, 15 kA Test number: 190823-7004 Phase A B C Applied voltage, phase-to-ground VRMS 583 583 583 Applied voltage, phase-to-phase VRMS 1010 Making current kApeak 20.9 10.2 17.4 Current, a.c. component, beginning kARMS 14.5 13.0 12.6 Current, a.c. component, middle kARMS 13.9 14.0 13.0 Current, a.c. component, end kARMS 13.6 14.6 12.7 Current, a.c. component, average kARMS 13.9 12.3 11.8 Current, a.c. component, three-phase kARMS 12.6 average Duration s 1.52 1.52 1.52 Arc energy kJ 6460 118 3655 Observations: Emission of flames and gas observed. Arc extinguished for approximately 12 ms on B & C phases before re-igniting. After this period, the arc was sustained on B & C phases for the remainder of the test.

KEMA Laboratories 24512323 12.4 Condition / inspection after test Bottom of box burned completely through. Sides of box heavily burned, but not burned through completely. There were two small holes on the side of the box towards the bottom of the box.

KEMA Laboratories 24512323 13 OPEN BOX TEST # 8 (OB08) - 1000 V, 30 KA Standard and date Standard Clients instructions Test date 23 August 2019 13.1 Condition before test Test device new. Arc to be initiated by #24 AWG wire. Arc wire connected to 1" diameter aluminum rods. Test duration is 1 second.

KEMA Laboratories 24512323 13.2 Test circuit S04 MB XS ABUB MS XP RP XFMR TD G V N

V V

G = Generator ABUB = Aux. Breaker R = Resistance N = Neutral XFMR = Transformer C = Capacitance MB = Main Breaker TD = Test Device V = Voltage Measurement MS = Make Switch X = Inductance I = Current Measurement Supply Power MVA 55.3 Frequency Hz 60 Phase(s) 3 Voltage V 1064 Sym. Current kA 30 Peak current kA 79.1 Impedance 0.020 Remarks: -

KEMA Laboratories 24512323 13.3 Test results and oscillograms Overview of test numbers 190823-7005 Remarks

KEMA Laboratories 24512323 Open Box Test # 8 - 1000 V, 30 kA Test number: 190823-7005 Phase A B C Applied voltage, phase-to-ground VRMS 614 614 614 Applied voltage, phase-to-phase VRMS 1063 Making current kApeak -47.0 45.7 -40.1 Current, a.c. component, beginning kARMS 28.8 28.0 26.0 Current, a.c. component, middle kARMS 27.7 28.1 26.2 Current, a.c. component, end kARMS 23.5 23.3 20.6 Current, a.c. component, average kARMS 26.1 24.8 23.9 Current, a.c. component, three-phase kARMS 24.9 average Duration s 1.01 1.01 1.01 Arc energy MJ 10.5 1.17 7.90 Observations: Emission of flames and gas observed.

KEMA Laboratories 24512323 13.4 Condition / inspection after test Small hole burned through bottom of box. Sides of box burned, but not completely through. B-phase aluminum rod ejected from the box. A and C phase rods were bent away from one another. Aluminum rods broke apart.

KEMA Laboratories 24512323 14 OPEN BOX TEST # 9 (OB11) - SINGLE PHASE INVESTIGATION Standard and date Standard Clients instructions Test date 23 August 2019 14.1 Condition before test Test box previously subject to arc tests on 8/23. Aluminum rods new. Arc to be initiated by #24 AWG wire. Arc wire connected to 1" diameter aluminum rods on B & C phase only. Test duration is 100 milliseconds. Purpose of the test is to measure how long it takes for arc to propagate to third phase.

KEMA Laboratories 24512323 14.2 Test circuit S05 MB XS ABUB MS XP RP XFMR TD G V N

V V

G = Generator ABUB = Aux. Breaker R = Resistance N = Neutral XFMR = Transformer C = Capacitance MB = Main Breaker TD = Test Device V = Voltage Measurement MS = Make Switch X = Inductance I = Current Measurement Supply Power MVA 26.2 Frequency Hz 60 Phase(s) 3 Voltage V 1009 Sym. Current kA 15 Peak current kA 40.4 Impedance 0.014 Remarks: Test conducted with arc wire only between two phases. Supply table above shows the available 3-phase circuit when arc propagated from 1-phase arc to 3-phase arc.

KEMA Laboratories 24512323 14.3 Test results and oscillograms Overview of test numbers 190823-7006 Remarks

KEMA Laboratories 24512323 Open Box Test # 9 - Single Phase Investigation Test number: 190823-7006 Phase A B C Applied voltage, phase-to-ground VRMS 583 583 583 Applied voltage, phase-to-phase VRMS 1010 Making current kApeak -25.9 18.8 -22.9 Current, a.c. component, beginning kARMS 15.1 9.44 11.2 Current, a.c. component, middle kARMS 15.4 12.7 11.2 Current, a.c. component, end kARMS 15.4 2.82 11.2 Current, a.c. component, average kARMS 15.2 11.7 11.9 Current, a.c. component, three-phase kARMS 12.9 average Duration s 0.114 0.120 0.117 Arc energy kJ 758 73.0 334 Observations: Emission of flames and gas observed. Arc propigated to A-phase rod in approximately 6 ms.

KEMA Laboratories 24512323 14.4 Condition / inspection after test Minimal damage to test box observed.

KEMA Laboratories 24512323 15 CHECKING THE PROSPECTIVE CURRENT Standard and date Standard Clients instructions Test date 26 August 2019 15.1 Condition before test Shorting bar connected at station terminals directly prior to test device.

KEMA Laboratories 24512323 15.2 Test results and oscillograms Overview of test numbers 190826-7001, 7002 Remarks Prospective circuit parameters calibrated in this test duty:

190826-7001: 616 V, 13.5 kA, 35.6 kA peak.

190826-7002: 489 V, 13.5 kA, 35.5 kA peak.

KEMA Laboratories 24512323 Checking the prospective current Test number: 190826-7001 Phase A B C Current kApeak 25.3 28.2 -34.7 Current, a.c. component kARMS 13.0 13.4 13.0 Current, a.c. component, three-phase kARMS 13.1 average Duration, current s 0.177 0.177 0.177 Observations: No visible disturbance.

KEMA Laboratories 24512323 Checking the prospective current Test number: 190826-7002 Phase A B C Current kApeak 25.1 28.9 -34.9 Current, a.c. component kARMS 13.0 13.6 13.2 Current, a.c. component, three-phase kARMS 13.3 average Duration, current s 0.177 0.177 0.176 Observations: No visible disturbance.

KEMA Laboratories 24512323 16 SAMPLE 2-13 (A) - 480 V, 13.5 KA Standard and date Standard Clients instructions Test date 26 August 2019 16.1 Condition before test Switchgear new. Arc to be initiated by #10 AWG stranded wire.

Pressure transducers # 1 & 2 located on right side of switchgear (when facing the front of the gear).

Pressure transducers # 3 & 4 located on left side of switchgear (when facing the front of the gear).

Pressure transducers # 1 & 3 are 0-50 PSI transducers.

Pressure transducers # 2 & 4 are 0-30 PSI transducers.

KEMA Laboratories 24512323 16.2 Test circuit S06 MB XS ABUB MS XP RP XFMR TD G V N

V V

G = Generator ABUB = Aux. Breaker R = Resistance N = Neutral XFMR = Transformer C = Capacitance MB = Main Breaker TD = Test Device V = Voltage Measurement MS = Make Switch X = Inductance I = Current Measurement Supply Power MVA 11.4 Frequency Hz 60 Phase(s) 3 Voltage V 489 Sym. Current kA 13.5 Peak current kA 35.5 Impedance 0.021 Remarks: -

KEMA Laboratories 24512323 16.3 Test results and oscillograms Overview of test numbers 190826-7003 Remarks Voltage traces for this test duty appear uneven on the oscillographs. This is due to the fact that station voltage dividers are referenced to ground. The test was conducted with the neutral of the wye transformer floating, so the station voltage dividers do not have a solid reference.

KEMA Laboratories 24512323 Sample 2-13 (A) - 480 V, 13.5 kA Test number: 190826-7003 Phase A B C Applied voltage, phase-to-ground VRMS 282 282 282 Applied voltage, phase-to-phase VRMS 488 Making current kApeak 24.0 23.8 -28.7 Current, a.c. component, beginning kARMS 10.7 11.9 10.2 Current, a.c. component, middle kARMS 7.52 9.15 5.89 Current, a.c. component, end kARMS 7.98 4.04 5.44 Current, a.c. component, average kARMS 8.78 9.35 7.71 Current, a.c. component, three-phase kARMS 8.61 average Duration s 0.519 0.519 0.519 Arc energy kJ 1122 28.9 554 Observations: Emission of flames and gas observed.

KEMA Laboratories 24512323 16.4 Condition / inspection after test Switchgear sustained minimal damage. Arc self-extinguished.

KEMA Laboratories 24512323 17 SAMPLE 2-13 (B) - 600 V, 13.5 KA Standard and date Standard Clients instructions Test date 27 August 2019 17.1 Condition before test Switchgear previously subjected to arc test at 480 V, 13.5 kA. Arc to be initiated by two #10 AWG stranded wires.

Pressure transducers # 1 & 2 located on right side of switchgear (when facing the front of the gear).

Pressure transducers # 3 & 4 located on left side of switchgear (when facing the front of the gear).

Pressure transducers # 1 & 3 are 0-50 PSI transducers.

Pressure transducers # 2 & 4 are 0-30 PSI transducers.

KEMA Laboratories 24512323 17.2 Test circuit S07 MB XS ABUB MS XP RP XFMR TD G V N

V V

G = Generator ABUB = Aux. Breaker R = Resistance N = Neutral XFMR = Transformer C = Capacitance MB = Main Breaker TD = Test Device V = Voltage Measurement MS = Make Switch X = Inductance I = Current Measurement Supply Power MVA 14.4 Frequency Hz 60 Phase(s) 3 Voltage V 616 Sym. Current kA 13.5 Peak current kA 35.6 Impedance 0.026 Remarks: -

KEMA Laboratories 24512323 17.3 Test results and oscillograms Overview of test numbers 190827-7001 Remarks

KEMA Laboratories 24512323 Sample 2-13 (B) - 600 V, 13.5 kA Test number: 190827-7001 Phase A B C Applied voltage, phase-to-ground VRMS 356 356 356 Applied voltage, phase-to-phase VRMS 617 Making current kApeak 24.7 28.5 -34.3 Current, a.c. component, beginning kARMS 13.4 14.0 2.05 Current, a.c. component, middle kARMS 8.76 7.33 6.74 Current, a.c. component, end kARMS 0.000 0.000 7.95 Current, a.c. component, average kARMS 9.91 9.46 8.27 Current, a.c. component, three-phase kARMS 9.22 average Duration s 0.332 0.332 0.396 Arc energy kJ 562 216 596 Observations: Emission of flames and gas observed.

KEMA Laboratories 24512323 17.4 Condition / inspection after test Switchgear sustained minimal damage. Arc self-extinguished.

KEMA Laboratories 24512323 18 SAMPLE 2-13 (C) - 600 V, 13.5 KA Standard and date Standard Clients instructions Test date 27 August 2019 18.1 Condition before test Switchgear in same condition as after trial 190827-7001. Arc to be initiated by two #10 AWG stranded wires. Additional grounding plate added to gear to attempt to sustain the arc.

Pressure transducers # 1 & 2 located on right side of switchgear (when facing the front of the gear).

Pressure transducers # 3 & 4 located on left side of switchgear (when facing the front of the gear).

Pressure transducers # 1 & 3 are 0-50 PSI transducers.

Pressure transducers # 2 & 4 are 0-30 PSI transducers.

KEMA Laboratories 24512323 18.2 Test circuit S07 MB XS ABUB MS XP RP XFMR TD G V N

V V

G = Generator ABUB = Aux. Breaker R = Resistance N = Neutral XFMR = Transformer C = Capacitance MB = Main Breaker TD = Test Device V = Voltage Measurement MS = Make Switch X = Inductance I = Current Measurement Supply Power MVA 14.4 Frequency Hz 60 Phase(s) 3 Voltage V 616 Sym. Current kA 13.5 Peak current kA 35.6 Impedance 0.026 Remarks: -

KEMA Laboratories 24512323 18.3 Test results and oscillograms Overview of test numbers 190827-7002 Remarks

KEMA Laboratories 24512323 Sample 2-13 (C) - 600 V, 13.5 kA Test number: 190827-7002 Phase A B C Applied voltage, phase-to-ground VRMS 356 356 356 Applied voltage, phase-to-phase VRMS 617 Making current kApeak 25.0 26.1 -34.4 Current, a.c. component, beginning kARMS 13.4 13.2 11.0 Current, a.c. component, middle kARMS 8.92 9.14 10.2 Current, a.c. component, end kARMS 7.93 4.10 8.05 Current, a.c. component, average kARMS 11.5 10.2 9.09 Current, a.c. component, three-phase kARMS 10.3 average Duration s 0.405 0.405 0.404 Arc energy kJ 705 342 601 Observations: Emission of flames and gas observed.

KEMA Laboratories 24512323 18.4 Condition / inspection after test Switchgear sustained minimal damage. Arc self-extinguished.

KEMA Laboratories 24512323 19 SAMPLE 2-13 (D) - 600 V, 13.5 KA Standard and date Standard Clients instructions Test date 27 August 2019 19.1 Condition before test Switchgear in same condition as after trial 190827-7002. Arc to be initiated by two #10 AWG stranded wires.

Pressure transducers # 1 & 2 located on right side of switchgear (when facing the front of the gear).

Pressure transducers # 3 & 4 located on left side of switchgear (when facing the front of the gear).

Pressure transducers # 1 & 3 are 0-50 PSI transducers.

Pressure transducers # 2 & 4 are 0-30 PSI transducers.

KEMA Laboratories 24512323 19.2 Test circuit S07 MB XS ABUB MS XP RP XFMR TD G V N

V V

G = Generator ABUB = Aux. Breaker R = Resistance N = Neutral XFMR = Transformer C = Capacitance MB = Main Breaker TD = Test Device V = Voltage Measurement MS = Make Switch X = Inductance I = Current Measurement Supply Power MVA 14.4 Frequency Hz 60 Phase(s) 3 Voltage V 616 Sym. Current kA 13.5 Peak current kA 35.6 Impedance 0.026 Remarks: -

KEMA Laboratories 24512323 19.3 Test results and oscillograms Overview of test numbers 190827-7003 Remarks

KEMA Laboratories 24512323 Sample 2-13 (D) - 600 V, 13.5 kA Test number: 190827-7003 Phase A B C Applied voltage, phase-to-ground VRMS 356 356 356 Applied voltage, phase-to-phase VRMS 617 Making current kApeak 24.7 28.4 -34.3 Current, a.c. component, beginning kARMS 13.4 13.5 12.2 Current, a.c. component, middle kARMS 9.05 13.7 11.8 Current, a.c. component, end kARMS 10.9 8.03 8.49 Current, a.c. component, average kARMS 11.2 10.1 9.88 Current, a.c. component, three-phase kARMS 10.4 average Duration s 0.924 0.924 0.924 Arc energy kJ 1754 1031 1356 Observations: Emission of flames and gas observed.

KEMA Laboratories 24512323 19.4 Condition / inspection after test Switchgear sustained minimal damage. Arc self-extinguished.

KEMA Laboratories 24512323 20 SAMPLE 2-13 (E) - 600 V, 13.5 KA Standard and date Standard Clients instructions Test date 27 August 2019 20.1 Condition before test Switchgear in same condition as after trial 190827-7003. Arc to be initiated by two #10 AWG stranded wires.

Pressure transducers # 1 & 2 located on right side of switchgear (when facing the front of the gear).

Pressure transducers # 3 & 4 located on left side of switchgear (when facing the front of the gear).

Pressure transducers # 1 & 3 are 0-50 PSI transducers.

Pressure transducers # 2 & 4 are 0-30 PSI transducers.

KEMA Laboratories 24512323 20.2 Test circuit S07 MB XS ABUB MS XP RP XFMR TD G V N

V V

G = Generator ABUB = Aux. Breaker R = Resistance N = Neutral XFMR = Transformer C = Capacitance MB = Main Breaker TD = Test Device V = Voltage Measurement MS = Make Switch X = Inductance I = Current Measurement Supply Power MVA 14.4 Frequency Hz 60 Phase(s) 3 Voltage V 616 Sym. Current kA 13.5 Peak current kA 35.6 Impedance 0.026 Remarks: -

KEMA Laboratories 24512323 20.3 Test results and oscillograms Overview of test numbers 190827-7004 Remarks

KEMA Laboratories 24512323 Sample 2-13 (E) - 600 V, 13.5 kA Test number: 190827-7004 Phase A B C Applied voltage, phase-to-ground VRMS 356 356 356 Applied voltage, phase-to-phase VRMS 617 Making current kApeak 24.9 28.4 -34.3 Current, a.c. component, beginning kARMS 12.6 13.5 11.6 Current, a.c. component, middle kARMS 10.4 10.5 9.79 Current, a.c. component, end kARMS 10.2 9.35 9.26 Current, a.c. component, average kARMS 11.1 10.8 10.00 Current, a.c. component, three-phase kARMS 10.6 average Duration s 2.06 2.06 2.06 Arc energy kJ 3497 2815 3289 Observations: Emission of flames and gas observed.

KEMA Laboratories 24512323 20.4 Condition / inspection after test Evidence of arcing found around the outside of the switchgear (burning and charring). No complete burn-throughs. Two of the breaker doors opened.

KEMA Laboratories 24512323 21 SAMPLE 2-13 (F) - 480 V, 13.5 KA Standard and date Standard Clients instructions Test date 28 August 2019 21.1 Condition before test Switchgear in same condition as after trial 190827-7004. Arc to be initiated by two #10 AWG stranded wires.

Pressure transducers # 1 & 2 located on right side of switchgear (when facing the front of the gear).

Pressure transducers # 3 & 4 located on left side of switchgear (when facing the front of the gear).

Pressure transducers # 1 & 3 are 0-50 PSI transducers.

Pressure transducers # 2 & 4 are 0-30 PSI transducers.

KEMA Laboratories 24512323 21.2 Test circuit S06 MB XS ABUB MS XP RP XFMR TD G V N

V V

G = Generator ABUB = Aux. Breaker R = Resistance N = Neutral XFMR = Transformer C = Capacitance MB = Main Breaker TD = Test Device V = Voltage Measurement MS = Make Switch X = Inductance I = Current Measurement Supply Power MVA 11.4 Frequency Hz 60 Phase(s) 3 Voltage V 489 Sym. Current kA 13.5 Peak current kA 35.5 Impedance 0.021 Remarks: -

KEMA Laboratories 24512323 21.3 Test results and oscillograms Overview of test numbers 190828-7001 Remarks

KEMA Laboratories 24512323 Sample 2-13 (F) - 480 V, 13.5 kA Test number: 190828-7001 Phase A B C Applied voltage, phase-to-ground VRMS 282 282 282 Applied voltage, phase-to-phase VRMS 488 Making current kApeak 24.7 28.4 -34.2 Current, a.c. component, beginning kARMS 13.1 13.6 12.8 Current, a.c. component, middle kARMS 8.32 9.92 7.61 Current, a.c. component, end kARMS 9.46 10.4 8.55 Current, a.c. component, average kARMS 10.3 9.95 9.26 Current, a.c. component, three-phase kARMS 9.84 average Duration s 1.55 1.32 1.32 Arc energy kJ 2119 1518 1732 Observations: Emission of flames and gas observed.

KEMA Laboratories 24512323 21.4 Condition / inspection after test Cable connected from enclosure of switchgear to neutral of supply transformer was ejected during test.

KEMA Laboratories -100- 24512323 22 SAMPLE 2-13 (G) - 600 V, 13.5 KA Standard and date Standard Clients instructions Test date 28 August 2019 22.1 Condition before test Switchgear in same condition as after trial 190828-7001. Arc to be initiated by two #10 AWG stranded wires.

Pressure transducers # 1 & 2 located on right side of switchgear (when facing the front of the gear).

Pressure transducers # 3 & 4 located on left side of switchgear (when facing the front of the gear).

Pressure transducers # 1 & 3 are 0-50 PSI transducers.

Pressure transducers # 2 & 4 are 0-30 PSI transducers.

KEMA Laboratories -101- 24512323 22.2 Test circuit S07 MB XS ABUB MS XP RP XFMR TD G V N

V V

G = Generator ABUB = Aux. Breaker R = Resistance N = Neutral XFMR = Transformer C = Capacitance MB = Main Breaker TD = Test Device V = Voltage Measurement MS = Make Switch X = Inductance I = Current Measurement Supply Power MVA 14.4 Frequency Hz 60 Phase(s) 3 Voltage V 616 Sym. Current kA 13.5 Peak current kA 35.6 Impedance 0.026 Remarks: -

KEMA Laboratories -102- 24512323 22.3 Test results and oscillograms Overview of test numbers 190828-7002 Remarks

KEMA Laboratories -103- 24512323 Sample 2-13 (G) - 600 V, 13.5 kA Test number: 190828-7002 Phase A B C Applied voltage, phase-to-ground VRMS 356 356 356 Applied voltage, phase-to-phase VRMS 617 Making current kApeak 25.1 26.6 -33.8 Current, a.c. component, beginning kARMS 14.0 13.1 13.0 Current, a.c. component, middle kARMS 9.62 12.1 9.18 Current, a.c. component, end kARMS 12.1 8.87 11.1 Current, a.c. component, average kARMS 12.3 10.8 11.0 Current, a.c. component, three-phase kARMS 11.4 average Duration s 2.04 2.04 2.04 Arc energy kJ 3525 3106 3646 Observations: Emission of flames and gas observed.

KEMA Laboratories -104- 24512323 22.4 Condition / inspection after test Switchgear burned, but otherwise structurally intact.

KEMA Laboratories -105- 24512323 23 CHECKING THE PROSPECTIVE CURRENT Standard and date Standard Clients instructions Test date 29 August 2019 23.1 Condition before test Shorting bar connected at station terminals directly prior to test device.

KEMA Laboratories -106- 24512323 23.2 Test results and oscillograms Overview of test numbers 190829-7001 to 7004 Remarks Prospective circuit parameters calibrated in this test duty:

190829-7001 and 190829-7002: 619 V, 25.0 kA, 63.3 kA peak.

190829-7003 and 190829-7004: 480 V, 25.6 kA, 64.5 kA peak.

KEMA Laboratories -107- 24512323 Checking the prospective current Test number: 190829-7001 Phase A B C Current kApeak -46.4 -50.1 61.5 Current, a.c. component kARMS 23.8 24.8 24.1 Current, a.c. component, three-phase kARMS 24.2 average Duration, current s 0.170 0.170 0.169 Observations: No visible disturbance.

KEMA Laboratories -108- 24512323 Checking the prospective current Test number: 190829-7002 Phase A B C Current kApeak 33.3 34.9 -33.7 Current, a.c. component kARMS 24.6 25.6 25.0 Current, a.c. component, three-phase kARMS 25.1 average Duration, current s 1.01 1.01 1.01 Observations: No visible disturbance. One second calibration to test super excitation.

KEMA Laboratories -109- 24512323 Checking the prospective current Test number: 190829-7003 Phase A B C Current kApeak -48.4 -53.2 64.6 Current, a.c. component kARMS 25.0 26.5 25.5 Current, a.c. component, three-phase kARMS 25.7 average Duration, current s 0.171 0.172 0.170 Observations: No visible disturbance.

KEMA Laboratories -110- 24512323 Checking the prospective current Test number: 190829-7004 Phase A B C Current kApeak 33.0 -35.3 -33.7 Current, a.c. component kARMS 24.7 26.2 25.0 Current, a.c. component, three-phase kARMS 25.3 average Duration, current s 1.01 1.01 1.01 Observations: No visible disturbance. One second calibration to check super excitation.

KEMA Laboratories -111- 24512323 24 SAMPLE 2-18 (A) - 480 V, 25 KA Standard and date Standard Clients instructions Test date 29 August 2019 24.1 Condition before test Switchgear new. Arc to be initiated by #10 AWG stranded wire.

Pressure transducers # 1 & 2 located on right side of switchgear (when facing the front of the gear).

Pressure transducers # 3 & 4 located on left side of switchgear (when facing the front of the gear).

Pressure transducers # 1 & 3 are 0-50 PSI transducers.

Pressure transducers # 2 & 4 are 0-30 PSI transducers.

KEMA Laboratories -112- 24512323 24.2 Test circuit S09 MB XS ABUB MS XP RP XFMR TD G V N

V V

G = Generator ABUB = Aux. Breaker R = Resistance N = Neutral XFMR = Transformer C = Capacitance MB = Main Breaker TD = Test Device V = Voltage Measurement MS = Make Switch X = Inductance I = Current Measurement Supply Power MVA 21.2 Frequency Hz 60 Phase(s) 3 Voltage V 480 Sym. Current kA 25.6 Peak current kA 64.5 Impedance 0.011 Remarks: -

KEMA Laboratories -113- 24512323 24.3 Test results and oscillograms Overview of test numbers 190829-7005 Remarks

KEMA Laboratories -114- 24512323 Sample 2-18 (A) - 480 V, 25 kA Test number: 190829-7005 Phase A B C Applied voltage, phase-to-ground VRMS 277 277 277 Applied voltage, phase-to-phase VRMS 480 Making current kApeak -41.4 -38.5 46.2 Current, a.c. component, beginning kARMS 23.5 21.0 22.4 Current, a.c. component, middle kARMS 20.7 23.5 16.6 Current, a.c. component, end kARMS 15.9 18.2 12.5 Current, a.c. component, average kARMS 19.8 17.3 17.9 Current, a.c. component, three-phase kARMS 18.3 average Duration s 2.02 2.02 2.02 Arc energy kJ 5925 5509 5597 Observations: Emission of flames and gas observed.

KEMA Laboratories -115- 24512323 24.4 Condition / inspection after test Evidence of arcing and burning found within the switchgear. Exterior of switchgear mostly intact.

KEMA Laboratories -116- 24512323 25 SAMPLE 2-18 (B) - 600 V, 25 KA Standard and date Standard Clients instructions Test date 29 August 2019 25.1 Condition before test Switchgear in same condition as after trial 190829-7005. Arc to be initiated by two #10 AWG stranded wires.

Pressure transducers # 1 & 2 located on right side of switchgear (when facing the front of the gear).

Pressure transducers # 3 & 4 located on left side of switchgear (when facing the front of the gear).

Pressure transducers # 1 & 3 are 0-50 PSI transducers.

Pressure transducers # 2 & 4 are 0-30 PSI transducers.

KEMA Laboratories -117- 24512323 25.2 Test circuit S08 MB XS ABUB MS XP RP XFMR TD G V N

V V

G = Generator ABUB = Aux. Breaker R = Resistance N = Neutral XFMR = Transformer C = Capacitance MB = Main Breaker TD = Test Device V = Voltage Measurement MS = Make Switch X = Inductance I = Current Measurement Supply Power MVA 26.8 Frequency Hz 60 Phase(s) 3 Voltage V 619 Sym. Current kA 25.0 Peak current kA 63.3 Impedance 0.014 Remarks: -

KEMA Laboratories -118- 24512323 25.3 Test results and oscillograms Overview of test numbers 190829-7006 Remarks

KEMA Laboratories -119- 24512323 Sample 2-18 (B) - 600 V, 25 kA Test number: 190829-7006 Phase A B C Applied voltage, phase-to-ground VRMS 357 357 357 Applied voltage, phase-to-phase VRMS 618 Making current kApeak 35.4 -38.8 -32.4 Current, a.c. component, beginning kARMS 22.6 20.9 22.0 Current, a.c. component, middle kARMS 25.8 23.6 21.9 Current, a.c. component, end kARMS 15.6 22.2 24.3 Current, a.c. component, average kARMS 21.1 20.0 19.6 Current, a.c. component, three-phase kARMS 20.2 average Duration s 8.30 8.30 8.30 Arc energy MJ 26.1 19.3 27.1 Observations: Emission of flames and gas observed.

KEMA Laboratories -120- 24512323 25.4 Condition / inspection after test Switchgear heavily damaged.

KEMA Laboratories -121- 24512323 26 OPEN BOX TEST # 10 (OB02) - 1000 V, 15 KA Standard and date Standard Clients instructions Test date 30 August 2019 26.1 Condition before test Test device new. Arc to be initiated by #24 AWG wire. Arc wire connected to 1" diameter copper rods.

Test duration is 2 seconds.

KEMA Laboratories -122- 24512323 26.2 Test circuit S03 MB XS ABUB MS XP RP XFMR TD G V N

V V

G = Generator ABUB = Aux. Breaker R = Resistance N = Neutral XFMR = Transformer C = Capacitance MB = Main Breaker TD = Test Device V = Voltage Measurement MS = Make Switch X = Inductance I = Current Measurement Supply Power MVA 26.2 Frequency Hz 60 Phase(s) 3 Voltage V 1009 Sym. Current kA 15 Peak current kA 40.4 Impedance 0.014 Remarks: -

KEMA Laboratories -123- 24512323 26.3 Test results and oscillograms Overview of test numbers 190830-7001 Remarks

KEMA Laboratories -124- 24512323 Open Box Test # 10 - 1000 V, 15 kA Test number: 190830-7001 Phase A B C Applied voltage, phase-to-ground VRMS 583 583 583 Applied voltage, phase-to-phase VRMS 1010 Making current kApeak -22.9 18.6 -22.7 Current, a.c. component, beginning kARMS 14.6 14.5 13.7 Current, a.c. component, middle kARMS 14.7 14.6 13.9 Current, a.c. component, end kARMS 13.7 14.2 12.4 Current, a.c. component, average kARMS 14.4 13.7 13.5 Current, a.c. component, three-phase kARMS 13.9 average Duration s 2.02 2.02 2.02 Arc energy kJ 4395 3277 4317 Observations: Emission of flames and gas observed.

KEMA Laboratories -125- 24512323 26.4 Condition / inspection after test Hole burned through bottom of box. Sides and rear of box heavily burned, but not completely through.

KEMA Laboratories -126- 24512323 27 OPEN BOX TEST # 11 (OB03) - 1000 V, 15 KA Standard and date Standard Clients instructions Test date 30 August 2019 27.1 Condition before test Test device new. Arc to be initiated by #24 AWG wire. Arc wire connected to 1" diameter copper rods.

Test duration is 3 seconds.

KEMA Laboratories -127- 24512323 27.2 Test circuit S03 MB XS ABUB MS XP RP XFMR TD G V N

V V

G = Generator ABUB = Aux. Breaker R = Resistance N = Neutral XFMR = Transformer C = Capacitance MB = Main Breaker TD = Test Device V = Voltage Measurement MS = Make Switch X = Inductance I = Current Measurement Supply Power MVA 26.2 Frequency Hz 60 Phase(s) 3 Voltage V 1009 Sym. Current kA 15 Peak current kA 40.4 Impedance 0.014 Remarks: -

KEMA Laboratories -128- 24512323 27.3 Test results and oscillograms Overview of test numbers 190830-7002 Remarks

KEMA Laboratories -129- 24512323 Open Box Test # 11 (OB03) - 1000 V, 15 kA Test number: 190830-7002 Phase A B C Applied voltage, phase-to-ground VRMS 583 583 583 Applied voltage, phase-to-phase VRMS 1010 Making current kApeak -19.4 -19.6 20.9 Current, a.c. component, beginning kARMS 14.7 14.6 13.4 Current, a.c. component, middle kARMS 14.9 14.2 12.4 Current, a.c. component, end kARMS 14.3 13.0 12.4 Current, a.c. component, average kARMS 14.4 13.5 13.1 Current, a.c. component, three-phase kARMS 13.6 average Duration s 3.03 3.03 3.02 Arc energy kJ 7347 5517 7022 Observations: Emission of flames and gas observed.

KEMA Laboratories -130- 24512323 27.4 Condition / inspection after test Bottom of box completely burned through. Sides of box towards bottom of box also burned through.

KEMA Laboratories -131- 24512323 28 OPEN BOX TEST # 12 (OB04) - 1000 V, 30 KA Standard and date Standard Clients instructions Test date 30 August 2019 28.1 Condition before test Test device new. Arc to be initiated by #24 AWG wire. Arc wire connected to 1" diameter copper rods.

Test duration is 1 seconds.

KEMA Laboratories -132- 24512323 28.2 Test circuit S04 MB XS ABUB MS XP RP XFMR TD G V N

V V

G = Generator ABUB = Aux. Breaker R = Resistance N = Neutral XFMR = Transformer C = Capacitance MB = Main Breaker TD = Test Device V = Voltage Measurement MS = Make Switch X = Inductance I = Current Measurement Supply Power MVA 55.3 Frequency Hz 60 Phase(s) 3 Voltage V 1064 Sym. Current kA 30 Peak current kA 79.1 Impedance 0.020 Remarks: -

KEMA Laboratories -133- 24512323 28.3 Test results and oscillograms Overview of test numbers 190830-7003 Remarks

KEMA Laboratories -134- 24512323 Open Box Test # 12 - 1000 V, 30 kA Test number: 190830-7003 Phase A B C Applied voltage, phase-to-ground VRMS 614 614 614 Applied voltage, phase-to-phase VRMS 1063 Making current kApeak 44.4 45.7 -44.6 Current, a.c. component, beginning kARMS 29.2 28.9 28.1 Current, a.c. component, middle kARMS 29.1 28.5 27.0 Current, a.c. component, end kARMS 28.0 28.5 25.1 Current, a.c. component, average kARMS 28.1 26.9 26.3 Current, a.c. component, three-phase kARMS 27.1 average Duration s 1.02 1.02 1.02 Arc energy kJ 4311 3419 4598 Observations: Emission of flames and gas observed.

KEMA Laboratories -135- 24512323 28.4 Condition / inspection after test Small hole burned through bottom of box. Sides of box heavily burned, but not completely through.

KEMA Laboratories -136- 24512323 29 OPEN BOX TEST # 13 (OB16) - SINGLE PHASE INVESTIGATION Standard and date Standard Clients instructions Test date 30 August 2019 29.1 Condition before test Test box new. Copper rods new. Arc to be initiated by #24 AWG wire. Arc wire connected to 1" diameter copper rods on A & B phase only. Test duration is 100 milliseconds. Purpose of the test is to measure how long it takes for arc to propagate to third phase.

KEMA Laboratories -137- 24512323 29.2 Test circuit S05 MB XS ABUB MS XP RP XFMR TD G V N

V V

G = Generator ABUB = Aux. Breaker R = Resistance N = Neutral XFMR = Transformer C = Capacitance MB = Main Breaker TD = Test Device V = Voltage Measurement MS = Make Switch X = Inductance I = Current Measurement Supply Power MVA 26.2 Frequency Hz 60 Phase(s) 3 Voltage V 1009 Sym. Current kA 15 Peak current kA 40.4 Impedance 0.014 Remarks: Test conducted with arc wire only between two phases. Supply table above shows the available 3-phase circuit when arc propagated from 1-phase arc to 3-phase arc.

KEMA Laboratories -138- 24512323 29.3 Test results and oscillograms Overview of test numbers 190830-7004 Remarks

KEMA Laboratories -139- 24512323 Open Box Test # 13 - Single Phase Investigation Test number: 190830-7004 Phase A B C Applied voltage, phase-to-ground VRMS 583 583 583 Applied voltage, phase-to-phase VRMS 1010 Making current kApeak 24.9 -15.7 -15.3 Current, a.c. component, beginning kARMS 16.0 9.35 8.47 Current, a.c. component, middle kARMS 15.2 14.1 13.4 Current, a.c. component, end kARMS 15.2 14.1 13.4 Current, a.c. component, average kARMS 14.9 11.1 11.7 Current, a.c. component, three-phase kARMS 12.6 average Duration s 0.118 0.118 0.116 Arc energy kJ 296 186 254 Observations: Emission of flames and gas observed. Arc propagation time is approximately 2.52 ms.

KEMA Laboratories -140- 24512323 29.4 Condition / inspection after test Minimal damage to test box observed.

KEMA Laboratories -141- 24512323 30 OPEN BOX TEST # 14 (OB12(A)) - SINGLE PHASE INVESTIGATION Standard and date Standard Clients instructions Test date 30 August 2019 30.1 Condition before test Test box in same condition as after trial 190830-7004. Arc to be initiated by #24 AWG wire. Arc wire connected to 1" diameter copper rod on C-phase & enclosure of box. Test duration is 100 milliseconds.

Purpose of the test is to measure how long it takes for arc to propagate to other two phases.

KEMA Laboratories -142- 24512323 30.2 Test circuit S05 MB XS ABUB MS XP RP XFMR TD G V N

V V

G = Generator ABUB = Aux. Breaker R = Resistance N = Neutral XFMR = Transformer C = Capacitance MB = Main Breaker TD = Test Device V = Voltage Measurement MS = Make Switch X = Inductance I = Current Measurement Supply Power MVA 26.2 Frequency Hz 60 Phase(s) 3 Voltage V 1009 Sym. Current kA 15 Peak current kA 40.4 Impedance 0.014 Remarks: Test conducted with arc wire only between two phases. Supply table above shows the available 3-phase circuit when arc propagated from 1-phase arc to 3-phase arc.

KEMA Laboratories -143- 24512323 30.3 Test results and oscillograms Overview of test numbers 190830-7005 Remarks

KEMA Laboratories -144- 24512323 Open Box Test # 14 - Single Phase Investigation Test number: 190830-7005 Phase A B C Applied voltage, phase-to-ground VRMS 583 583 583 Applied voltage, phase-to-phase VRMS 1010 Making current kApeak -18.2 26.1 -25.8 Current, a.c. component, beginning kARMS 12.1 12.5 11.4 Current, a.c. component, middle kARMS 15.1 14.2 13.1 Current, a.c. component, end kARMS 15.1 14.2 13.1 Current, a.c. component, average kARMS 14.0 13.7 12.7 Current, a.c. component, three-phase kARMS 13.5 average Duration s 0.113 0.112 0.113 Arc energy kJ 267 206 230 Observations: Emission of flames and gas observed. Arc propagation time was approximately 400 us.

KEMA Laboratories -145- 24512323 30.4 Condition / inspection after test Minimal damage to test box observed.

KEMA Laboratories -146- 24512323 31 OPEN BOX TEST # 15 (OB15) - SINGLE PHASE INVESTIGATION Standard and date Standard Clients instructions Test date 30 August 2019 31.1 Condition before test Test box in same condition as after trial 190830-7005. Arc to be initiated by #24 AWG wire. Arc wire connected to 1" diameter aluminum rod on B-phase & enclosure of box. Test duration is 100 milliseconds. Purpose of the test is to measure how long it takes for arc to propagate to other two phases.

KEMA Laboratories -147- 24512323 31.2 Test circuit S05 MB XS ABUB MS XP RP XFMR TD G V N

V V

G = Generator ABUB = Aux. Breaker R = Resistance N = Neutral XFMR = Transformer C = Capacitance MB = Main Breaker TD = Test Device V = Voltage Measurement MS = Make Switch X = Inductance I = Current Measurement Supply Power MVA 26.2 Frequency Hz 60 Phase(s) 3 Voltage V 1009 Sym. Current kA 15 Peak current kA 40.4 Impedance 0.014 Remarks: Test conducted with arc wire only between two phases. Supply table above shows the available 3-phase circuit when arc propagated from 1-phase arc to 3-phase arc.

KEMA Laboratories -148- 24512323 31.3 Test results and oscillograms Overview of test numbers 190830-7006 Remarks

KEMA Laboratories -149- 24512323 Open Box Test # 15 - Single Phase Investigation Test number: 190830-7006 Phase A B C Applied voltage, phase-to-ground VRMS 583 583 583 Applied voltage, phase-to-phase VRMS 1010 Making current kApeak - -5.51 -

Current, a.c. component, beginning kARMS - 0.974 -

Current, a.c. component, middle kARMS - 0.000 -

Current, a.c. component, end kARMS 0.000 0.000 0.000 Current, a.c. component, average kARMS - - -

Current, a.c. component, three-phase kARMS -

average Duration s - 0.148 -

Arc energy kJ -

Observations: Small flash observed. Arc did not propagate to other phases.

KEMA Laboratories -150- 24512323 31.4 Condition / inspection after test Arc failed to propagate to other phases.

KEMA Laboratories -151- 24512323 32 OPEN BOX TEST # 16 (OB14) - SINGLE PHASE INVESTIGATION Standard and date Standard Clients instructions Test date 30 August 2019 32.1 Condition before test Test box in same condition as after trial 190830-7006. Arc to be initiated by #24 AWG wire. Arc wire connected to 1" diameter aluminum rod on A-phase & enclosure of box. Test duration is 100 milliseconds. Purpose of the test is to measure how long it takes for arc to propagate to other two phases.

KEMA Laboratories -152- 24512323 32.2 Test circuit S05 MB XS ABUB MS XP RP XFMR TD G V N

V V

G = Generator ABUB = Aux. Breaker R = Resistance N = Neutral XFMR = Transformer C = Capacitance MB = Main Breaker TD = Test Device V = Voltage Measurement MS = Make Switch X = Inductance I = Current Measurement Supply Power MVA 26.2 Frequency Hz 60 Phase(s) 3 Voltage V 1009 Sym. Current kA 15 Peak current kA 40.4 Impedance 0.014 Remarks: Test conducted with arc wire only between two phases. Supply table above shows the available 3-phase circuit when arc propagated from 1-phase arc to 3-phase arc.

KEMA Laboratories -153- 24512323 32.3 Test results and oscillograms Overview of test numbers 190830-7007 Remarks

KEMA Laboratories -154- 24512323 Open Box Test # 16 - Single Phase Investigation Test number: 190830-7007 Phase A B C Applied voltage, phase-to-ground VRMS 583 583 583 Applied voltage, phase-to-phase VRMS 1010 Making current kApeak -22.3 -20.3 20.8 Current, a.c. component, beginning kARMS 14.0 12.4 13.1 Current, a.c. component, middle kARMS 14.4 14.3 13.4 Current, a.c. component, end kARMS 14.5 14.5 13.0 Current, a.c. component, average kARMS 14.4 13.9 13.0 Current, a.c. component, three-phase kARMS 13.8 average Duration s 0.137 0.132 0.126 Arc energy kJ 373 257 300 Observations: Emission of flames and gas observed. Arc propagated to B-phase in approximately 4.8 ms. Arc propagated to C-phase in approximately 10 ms.

KEMA Laboratories -155- 24512323 32.4 Condition / inspection after test Minimal damage to test box observed.

KEMA Laboratories -156- 24512323 33 OPEN BOX TEST # 17 (OB12(B) & OB12(C)) - SINGLE PHASE INVESTIGATION Standard and date Standard Clients instructions Test date 30 August 2019 33.1 Condition before test Test box in same condition as after trial 190830-7007. Arc to be initiated by #24 AWG wire. Arc wire connected to 1" diameter copper rod on C-phase & enclosure of box. Test duration is 100 milliseconds.

Purpose of the test is to measure how long it takes for arc to propagate to other two phases.

KEMA Laboratories -157- 24512323 33.2 Test circuit S05 MB XS ABUB MS XP RP XFMR TD G V N

V V

G = Generator ABUB = Aux. Breaker R = Resistance N = Neutral XFMR = Transformer C = Capacitance MB = Main Breaker TD = Test Device V = Voltage Measurement MS = Make Switch X = Inductance I = Current Measurement Supply Power MVA 26.2 Frequency Hz 60 Phase(s) 3 Voltage V 1009 Sym. Current kA 15 Peak current kA 40.4 Impedance 0.014 Remarks: Test conducted with arc wire only between two phases. Supply table above shows the available 3-phase circuit when arc propagated from 1-phase arc to 3-phase arc.

KEMA Laboratories -158- 24512323 33.3 Test results and oscillograms Overview of test numbers 190830-7008, 7009 Remarks

KEMA Laboratories -159- 24512323 Open Box Test # 17 - Single Phase Investigation Test number: 190830-7008 Phase A B C Applied voltage, phase-to-ground VRMS 583 583 583 Applied voltage, phase-to-phase VRMS 1010 Making current kApeak 28.9 -30.9 -19.7 Current, a.c. component, beginning kARMS 14.8 16.2 8.35 Current, a.c. component, middle kARMS 14.3 14.7 13.8 Current, a.c. component, end kARMS 14.6 14.7 13.8 Current, a.c. component, average kARMS 14.6 14.5 12.4 Current, a.c. component, three-phase kARMS 13.8 average Duration s 0.122 0.118 0.121 2

Arc energy kJ 269 211 6 7

Observations: Emission of flames and gas observed. Current was present on both A and C phases immediately upon closing onto the test device. This test will be repeated.

KEMA Laboratories -160- 24512323 Open Box Test # 17 - Single Phase Investigation Test number: 190830-7009 Phase A B C Applied voltage, phase-to-ground VRMS 583 583 583 Applied voltage, phase-to-phase VRMS 1010 Making current kApeak 22.5 19.0 -17.8 Current, a.c. component, beginning kARMS 13.1 12.2 11.1 Current, a.c. component, middle kARMS 14.7 14.1 13.6 Current, a.c. component, end kARMS 14.7 14.1 13.6 Current, a.c. component, average kARMS 14.5 13.7 13.1 Current, a.c. component, three-phase kARMS 13.8 average Duration s 0.117 0.119 0.123 Arc energy kJ 269 206 258 Observations: Emission of flames and gas observed. Arc propagated to B phase in 4.4 ms, to A phase in 5.9 ms.

KEMA Laboratories -161- 24512323 33.4 Condition / inspection after test Box sustained minimal damage.

KEMA Laboratories -162- 24512323 34 OPEN BOX TEST # 18 - 480 V, 13.5 KA Standard and date Standard Clients instructions Test date 30 August 2019 34.1 Condition before test Test box in same condition as after trial 190830-7009. Arc to be initiated by #10 AWG wire. Arc wire connected to 1" diameter copper rods. Test duration is 2 seconds.

KEMA Laboratories -163- 24512323 34.2 Test circuit S06 MB XS ABUB MS XP RP XFMR TD G V N

V V

G = Generator ABUB = Aux. Breaker R = Resistance N = Neutral XFMR = Transformer C = Capacitance MB = Main Breaker TD = Test Device V = Voltage Measurement MS = Make Switch X = Inductance I = Current Measurement Supply Power MVA 11.4 Frequency Hz 60 Phase(s) 3 Voltage V 489 Sym. Current kA 13.5 Peak current kA 35.5 Impedance 0.021 Remarks: -

KEMA Laboratories -164- 24512323 34.3 Test results and oscillograms Overview of test numbers 190830-7010 Remarks

KEMA Laboratories -165- 24512323 Open Box Test # 18 - 480 V, 13.5 kA Test number: 190830-7010 Phase A B C Applied voltage, phase-to-ground VRMS 282 282 282 Applied voltage, phase-to-phase VRMS 488 Making current kApeak 24.7 13.1 -30.6 Current, a.c. component, beginning kARMS 3.19 5.07 5.41 Current, a.c. component, middle kARMS 0.975 2.32 0.000 Current, a.c. component, end kARMS 0.000 0.000 0.000 Current, a.c. component, average kARMS 0.000 0.000 -

Current, a.c. component, three-phase kARMS -

average Duration ms 12.7 10.9 10.6 Arc energy kJ 11.4 13.2 34.9 Observations: Emission of flames and gas observed.

KEMA Laboratories -166- 24512323 34.4 Condition / inspection after test Box sustained minimal damage. Arc self-extinguished.

KEMA Laboratories -167- 24512323 35 CHECKING THE PROSPECTIVE CURRENT Standard and date Standard Clients instructions Test date 16 September 2019 35.1 Condition before test Shorting bar connected at station terminals directly prior to test device.

KEMA Laboratories -168- 24512323 35.2 Test results and oscillograms Overview of test numbers 190916-9002 to 9005 Remarks Prospective circuit parameters calibrated in this test duty:

190916-90029003: 6900 V, 15.3 kA, 42.9 kA peak.

190916-90049005: 6900 V, 30.6 kA, 86.5 kA peak.

KEMA Laboratories -169- 24512323 Checking the prospective current Test number: 190916-9002 Phase A B C Current kApeak -42.9 32.8 32.6 Current, a.c. component kARMS 15.4 15.5 15.1 Current, a.c. component, three-phase kARMS 15.3 average Duration, current s 0.171 0.171 0.171 Observations: No visible disturbance.

KEMA Laboratories -170- 24512323 Checking the prospective current Test number: 190916-9003 Phase A B C Current kApeak -43.0 33.1 32.5 Current, a.c. component kARMS 14.0 14.2 13.4 Current, a.c. component, three-phase kARMS 13.9 average Duration, current s 1.03 1.03 1.03 Observations: No visible disturbance.

KEMA Laboratories -171- 24512323 Checking the prospective current Test number: 190916-9004 Phase A B C Current kApeak -85.8 67.7 65.4 Current, a.c. component kARMS 30.2 31.6 30.0 Current, a.c. component, three-phase kARMS 30.6 average Duration, current s 0.166 0.166 0.166 Observations: No visible disturbance.

KEMA Laboratories -172- 24512323 Checking the prospective current Test number: 190916-9005 Phase A B C Current kApeak -86.5 70.0 64.6 Current, a.c. component, beginning kARMS 30.1 31.3 30.2 Current, a.c. component, middle kARMS 28.2 29.4 28.3 Current, a.c. component, end kARMS 28.0 29.2 28.1 Current, a.c. component, average kARMS 29.0 30.2 29.1 Current, a.c. component, three-phase kARMS 29.4 average Duration, current s 1.07 1.07 1.07 Observations: No visible disturbance.

KEMA Laboratories -173- 24512323 36 OBMV # 5 Standard and date Standard Clients instructions Test date 16 September 2019 36.1 Condition before test Test device new. Arc to be initiated by #24 AWG wire. Arc wire connected to copper bus. Test duration is 2 seconds.

KEMA Laboratories -174- 24512323 36.2 Test circuit S11 MB XS ABUB MS TD G V N

V V

G = Generator ABUB = Aux. Breaker R = Resistance N = Neutral XFMR = Transformer C = Capacitance MB = Main Breaker TD = Test Device V = Voltage Measurement MS = Make Switch X = Inductance I = Current Measurement Supply Power MVA 366 Frequency Hz 60 Phase(s) 3 Voltage V 6900 Sym. Current kA 30.6 Peak current kA 86.5 Impedance 0.130 Remarks: -

KEMA Laboratories -175- 24512323 36.3 Test results and oscillograms Overview of test numbers 190916-9006 Remarks

KEMA Laboratories -176- 24512323 OBMV # 5 Test number: 190916-9006 Phase A B C Applied voltage, phase-to-ground kVRMS 3.98 3.98 3.98 Applied voltage, phase-to-phase kVRMS 6.90 Making current kApeak -78.3 62.1 64.5 Current, a.c. component, beginning kARMS 31.7 32.9 31.9 Current, a.c. component, middle kARMS 27.3 28.3 27.9 Current, a.c. component, end kARMS 27.4 28.2 27.4 Current, a.c. component, average kARMS 28.3 29.1 28.6 Current, a.c. component, three-phase kARMS 28.7 average Duration s 2.32 2.32 2.32 Arc energy MJ 15.7 12.7 15.1 Observations: Emission of flames and gas observed.

KEMA Laboratories -177- 24512323 36.4 Condition / inspection after test Left and right side of box burned through. Bottom of box melted and heavily distorted, but no burn-throughs evident.

KEMA Laboratories -178- 24512323 37 OBMV # 2 Standard and date Standard Clients instructions Test date 17 September 2019 37.1 Condition before test Test device new. Arc to be initiated by #24 AWG wire. Arc wire connected to aluminum bus. Test duration is 1 seconds.

KEMA Laboratories -179- 24512323 37.2 Test circuit S11 MB XS ABUB MS TD G V N

V V

G = Generator ABUB = Aux. Breaker R = Resistance N = Neutral XFMR = Transformer C = Capacitance MB = Main Breaker TD = Test Device V = Voltage Measurement MS = Make Switch X = Inductance I = Current Measurement Supply Power MVA 366 Frequency Hz 60 Phase(s) 3 Voltage V 6900 Sym. Current kA 30.6 Peak current kA 86.5 Impedance 0.130 Remarks: -

KEMA Laboratories -180- 24512323 37.3 Test results and oscillograms Overview of test numbers 190917-9001 Remarks

KEMA Laboratories -181- 24512323 OBMV # 2 Test number: 190917-9001 Phase A B C Applied voltage, phase-to-ground kVRMS 3.98 3.98 3.98 Applied voltage, phase-to-phase kVRMS 6.89 Making current kApeak -77.4 62.5 62.2 Current, a.c. component, beginning kARMS 32.0 32.7 31.5 Current, a.c. component, middle kARMS 27.7 28.5 28.5 Current, a.c. component, end kARMS 27.8 28.5 27.9 Current, a.c. component, average kARMS 28.7 29.5 29.0 Current, a.c. component, three-phase kARMS 29.0 average Duration s 1.11 1.11 1.11 Arc energy MJ 6.58 8.07 6.77 Observations: Emission of flames and gas observed.

KEMA Laboratories -182- 24512323 37.4 Condition / inspection after test No complete burn throughs evident.

KEMA Laboratories -183- 24512323 38 OBMV # 4 Standard and date Standard Clients instructions Test date 17 September 2019 38.1 Condition before test Test device new. Arc to be initiated by #24 AWG wire. Arc wire connected to copper bus. Test duration is 5 seconds.

KEMA Laboratories -184- 24512323 38.2 Test circuit S10 MB XS ABUB MS TD G V N

V V

G = Generator ABUB = Aux. Breaker R = Resistance N = Neutral XFMR = Transformer C = Capacitance MB = Main Breaker TD = Test Device V = Voltage Measurement MS = Make Switch X = Inductance I = Current Measurement Supply Power MVA 182 Frequency Hz 60 Phase(s) 3 Voltage V 6900 Sym. Current kA 15.3 Peak current kA 42.9 Impedance 0.260 Remarks: -

KEMA Laboratories -185- 24512323 38.3 Test results and oscillograms Overview of test numbers 190917-9002 Remarks

KEMA Laboratories -186- 24512323 OBMV # 4 Test number: 190917-9002 Phase A B C Applied voltage, phase-to-ground kVRMS 3.98 3.98 3.98 Applied voltage, phase-to-phase kVRMS 6.89 Making current kApeak -40.7 31.0 29.9 Current, a.c. component, beginning kARMS 16.1 16.2 15.2 Current, a.c. component, middle kARMS 14.1 14.0 13.7 Current, a.c. component, end kARMS 14.5 14.2 14.0 Current, a.c. component, average kARMS 14.6 14.5 14.1 Current, a.c. component, three-phase kARMS 14.4 average Duration s 5.08 5.08 5.08 Arc energy MJ 16.7 19.1 16.0 Observations: Emission of flames and gas observed.

KEMA Laboratories -187- 24512323 38.4 Condition / inspection after test Bottom of box burned completely through. Large burn throughs evident on sides of box.

KEMA Laboratories -188- 24512323 39 OBMV # 1 Standard and date Standard Clients instructions Test date 18 September 2019 39.1 Condition before test Test device new. Arc to be initiated by #24 AWG wire. Arc wire connected to aluminum bus. Test duration is 2 seconds.

KEMA Laboratories -189- 24512323 39.2 Test circuit S10 MB XS ABUB MS TD G V N

V V

G = Generator ABUB = Aux. Breaker R = Resistance N = Neutral XFMR = Transformer C = Capacitance MB = Main Breaker TD = Test Device V = Voltage Measurement MS = Make Switch X = Inductance I = Current Measurement Supply Power MVA 182 Frequency Hz 60 Phase(s) 3 Voltage V 6900 Sym. Current kA 15.3 Peak current kA 42.9 Impedance 0.260 Remarks: -

KEMA Laboratories -190- 24512323 39.3 Test results and oscillograms Overview of test numbers 190918-9001 Remarks

KEMA Laboratories -191- 24512323 OBMV # 1 Test number: 190918-9001 Phase A B C Applied voltage, phase-to-ground kVRMS 3.98 3.98 3.98 Applied voltage, phase-to-phase kVRMS 6.89 Making current kApeak -40.6 31.6 31.2 Current, a.c. component, beginning kARMS 16.2 15.8 15.5 Current, a.c. component, middle kARMS 14.2 14.2 13.6 Current, a.c. component, end kARMS 14.3 14.4 13.6 Current, a.c. component, average kARMS 14.7 14.5 14.1 Current, a.c. component, three-phase kARMS 14.4 average Duration s 3.18 3.18 3.18 Arc energy MJ 12.4 13.3 11.8 Observations: Emission of flames and gas observed. Station timer malfunctioned during test, causing duration to be extended to 3.18 seconds.

KEMA Laboratories -192- 24512323 39.4 Condition / inspection after test Bottom and sides of box completely burned through. Test duration was longer than expected due to station timer malfunction.

KEMA Laboratories -193- 24512323 40 OBMV # 3 Standard and date Standard Clients instructions Test date 18 September 2019 40.1 Condition before test Test device new. Arc to be initiated by #24 AWG wire. Arc wire connected to aluminum bus. Test duration is 5 seconds.

KEMA Laboratories -194- 24512323 40.2 Test circuit S10 MB XS ABUB MS TD G V N

V V

G = Generator ABUB = Aux. Breaker R = Resistance N = Neutral XFMR = Transformer C = Capacitance MB = Main Breaker TD = Test Device V = Voltage Measurement MS = Make Switch X = Inductance I = Current Measurement Supply Power MVA 182 Frequency Hz 60 Phase(s) 3 Voltage V 6900 Sym. Current kA 15.3 Peak current kA 42.9 Impedance 0.260 Remarks: -

KEMA Laboratories -195- 24512323 40.3 Test results and oscillograms Overview of test numbers 190918-9002 Remarks

KEMA Laboratories -196- 24512323 OBMV # 3 Test number: 190918-9002 Phase A B C Applied voltage, phase-to-ground kVRMS 3.98 3.98 3.98 Applied voltage, phase-to-phase kVRMS 6.89 Making current kApeak -40.5 32.1 29.7 Current, a.c. component, beginning kARMS 15.9 15.9 15.3 Current, a.c. component, middle kARMS 14.2 14.0 13.9 Current, a.c. component, end kARMS 14.7 14.1 14.1 Current, a.c. component, average kARMS 14.7 14.4 14.1 Current, a.c. component, three-phase kARMS 14.4 average Duration s 5.05 5.05 5.05 Arc energy MJ 19.1 19.6 17.0 Observations: Emission of flames and gas observed.

KEMA Laboratories -197- 24512323 40.4 Condition / inspection after test Bottom and sides of box completely burned through.

KEMA Laboratories -198- 24512323 41 OBMV # 6 Standard and date Standard Clients instructions Test date 18 September 2019 41.1 Condition before test Test device new. Arc to be initiated by #24 AWG wire. Arc wire connected to aluminum bus. Test duration is 2 seconds.

KEMA Laboratories -199- 24512323 41.2 Test circuit S10 MB XS ABUB MS TD G V N

V V

G = Generator ABUB = Aux. Breaker R = Resistance N = Neutral XFMR = Transformer C = Capacitance MB = Main Breaker TD = Test Device V = Voltage Measurement MS = Make Switch X = Inductance I = Current Measurement Supply Power MVA 182 Frequency Hz 60 Phase(s) 3 Voltage V 6900 Sym. Current kA 15.3 Peak current kA 42.9 Impedance 0.260 Remarks: -

KEMA Laboratories -200- 24512323 41.3 Test results and oscillograms Overview of test numbers 190918-9003 Remarks

KEMA Laboratories -201- 24512323 OBMV # 6 Test number: 190918-9003 Phase A B C Applied voltage, phase-to-ground kVRMS 3.98 3.98 3.98 Applied voltage, phase-to-phase kVRMS 6.89 Making current kApeak -40.7 32.1 30.5 Current, a.c. component, beginning kARMS 15.9 16.0 15.5 Current, a.c. component, middle kARMS 14.5 14.1 13.9 Current, a.c. component, end kARMS 14.7 13.9 13.9 Current, a.c. component, average kARMS 14.8 14.6 14.3 Current, a.c. component, three-phase kARMS 14.6 average Duration s 2.05 2.05 2.05 Arc energy MJ 7.66 7.89 7.17 Observations: Emission of flames and gas observed.

KEMA Laboratories -202- 24512323 41.4 Condition / inspection after test Bottom and sides of box completely burned through.

KEMA Laboratories -203- 24512323 42 ATTACHMENTS

1. Calorimeter Data Records [15 PAGES]

2. Instrumentation Information Sheets [2 PAGES]

3. Photographs (269) [135 PAGES]

Test Number: 24512323 Date and Time:

Trial Number: 190826-7003 8/26/2019 DAS Operator: Joe Duffy 4:18:00 PM Calorimeter Avg Start Temp (°C) Max Temp (°C) Time to max heat (sec) Comments A 44.6 44.6 N/A 1,2 B 23.8 23.8 N/A 1 C 23.9 23.9 N/A 1 D 23.3 23.3 N/A 1 E 24.6 24.6 N/A 1 F 40.7 40.7 N/A 1,2 G 24.8 24.8 N/A 1 H 43.7 43.7 N/A 1,2 I 50.7 50.7 N/A 1,2 J 24.5 24.5 N/A 1 Comments: 1) Due to the arc self-extinguishing, no noticeable differences in temperature during the event were recorded. 2) Ambient temperature readings were much higher than actual ambient, client agreed to proceed with testing despite this difference.

REPORT # 24512323 Calorimeter Data Records

Test Number: 24512323 Date and Time:

Trial Number: 190827-7001 8/27/2019 DAS Operator: Joe Duffy 9:16:00 AM Calorimeter Avg Start Temp (°C) Max Temp (°C) Time to max heat (sec) Comments A 32.0 32.1 N/A 1,2 B 18.2 18.2 N/A 1 C 18.9 18.9 N/A 1 D 18.4 18.9 N/A 1 E 18.5 19.0 N/A 1 F 26.3 26.8 55 2 G 19.7 20.8 30 H 29.8 31.0 58 2 I 36.0 36.8 23 2 J 19.0 19.4 11 Comments: 1) Due to the arc self-extinguishing, no noticeable differences in temperature during the event were recorded. 2) Ambient temperature readings were much higher than actual ambient, client agreed to proceed with testing despite this difference.

REPORT # 24512323 Calorimeter Data Records

Test Number: 24512323 Date and Time:

Trial Number: 190827-7002 8/27/2019 DAS Operator: Joe Duffy 10:25:00 AM Calorimeter Avg Start Temp (°C) Max Temp (°C) Time to max heat (sec) Comments A 41.3 41.7 N/A 1,2 B 20.1 20.3 N/A 1 C 20.5 20.6 N/A 1 D 19.7 19.8 N/A 1 E 20.1 21.0 101 F 34.7 35.6 110 2 G 20.4 21.4 9 H 38.4 39.6 17 2 I 44.4 45.1 30 2 J 20.5 21.2 33 Comments: 1) Due to the arc self-extinguishing, no noticeable differences in temperature during the event were recorded. 2) Ambient temperature readings were much higher than actual ambient, client agreed to proceed with testing despite this difference.

REPORT # 24512323 Calorimeter Data Records

Test Number: 24512323 Date and Time:

Trial Number: 190827-7003 8/27/2019 DAS Operator: Joe Duffy 1:24:00 PM Calorimeter Avg Start Temp (°C) Max Temp (°C) Time to max heat (sec) Comments A 50.0 50.4 N/A 1,2 B 23.1 23.2 N/A 1 C 23.8 23.8 N/A 1 D 22.4 22.5 N/A 1 E 23.7 26.7 158 F 43.1 45.2 151 2 G 23.5 26.4 80 H 46.6 50.3 171 2 I 52.3 54.1 99 2 J 23.2 24.2 140 Comments: 1) Due to the arc self-extinguishing, no noticeable differences in temperature during the event were recorded. 2) Ambient temperature readings were much higher than actual ambient, client agreed to proceed with testing despite this difference.

REPORT # 24512323 Calorimeter Data Records

Test Number: 24512323 Date and Time:

Trial Number: 190827-7004 8/27/2019 DAS Operator: Joe Duffy 2:54:00 PM Calorimeter Avg Start Temp (°C) Max Temp (°C) Time to max heat (sec) Comments A 53.6 53.8 N/A 1,2 B 24.6 24.7 N/A 1 C 24.8 26.2 11 D 23.8 24.9 137 E 24.7 25.5 33 F 47.1 50.0 >10 minutes 2,3 G 24.6 40.5 9 H 50.8 57.0 147 2 I 56.7 56.5 11 2 J 25.4 28.7 9 Comments: 1) No significant difference in temperature during the event were recorded. 2) Ambient temperature readings were much higher than actual ambient, client agreed to proceed with testing despite this difference. 3) Temperature appears to still be rising at the end of the data capture window.

REPORT # 24512323 Calorimeter Data Records

Test Number: 24512323 Date and Time:

Trial Number: 190828-7001 8/28/2019 DAS Operator: Joe Duffy 10:14:00 AM Calorimeter Avg Start Temp (°C) Max Temp (°C) Time to max heat (sec) Comments A 64.5 70.9 7 1 B 30.5 41.2 4 C 26.3 27.0 260 D 24.8 25.3 260 E 29.5 30.5 124 F 56.5 58.1 290 1,2 G 27.2 28.5 135 H 59.1 60.4 101 1 I 63.7 64.4 160 1 J 27.3 28.2 290 2 Comments: 1) Ambient temperature readings were much higher than actual ambient, client agreed to proceed with testing despite this difference. 2) Temperature appears to still be rising at the end of the data capture window.

REPORT # 24512323 Calorimeter Data Records

Test Number: 24512323 Date and Time:

Trial Number: 190828-7002 8/28/2019 DAS Operator: Joe Duffy 10:53:00 AM Calorimeter Avg Start Temp (°C) Max Temp (°C) Time to max heat (sec) Comments A 61.2 74.3 6 2 B 28.1 47.5 6 C 27.8 27.9 N/A 1 D 26.9 27.0 N/A 1 E 27.8 29.4 6 F 54.6 56.3 290 2,3 G 27.7 30.7 47 H 58.0 63.0 10 2 I 63.9 65.6 58 2 J 27.8 29.7 9 Comments: 1) No significant difference in temperature during the event were recorded. 2) Ambient temperature readings were much higher than actual ambient, client agreed to proceed with testing despite this difference. 3) Temperature appears to still be rising at the end of the data capture window.

REPORT # 24512323 Calorimeter Data Records

Test Number: 24512323 Date and Time:

Trial Number: 190829-7005 8/29/2019 DAS Operator: Joe Duffy 11:21:00 AM Calorimeter Avg Start Temp (°C) Max Temp (°C) Time to max heat (sec) Comments A 62.8 73.0 6 1 B 31.8 46.6 5 C 27.1 28.0 >7 minutes 2 D 26.3 27.1 >7 minutes 2 E 28.7 33.4 234 F 54.3 58.5 >7 minutes 1,2 G 28.7 40.2 176 H 59.3 75.3 21 1 I 64.0 68.7 277 1 J 30.1 35.2 9 K 30.0 32.5 268 L 28.0 30.7 >7 minutes 2 Comments: 1) Ambient temperature readings were much higher than actual ambient, client agreed to proceed with testing despite this difference. 2) Temperature appears to still be rising at the end of the data capture window.

REPORT # 24512323 Calorimeter Data Records

Test Number: 24512323 Date and Time:

Trial Number: 190829-7006 8/29/2019 DAS Operator: Joe Duffy 2:31:00 PM Calorimeter Avg Start Temp (°C) Max Temp (°C) Time to max heat (sec) Comments A 56.2 120.0 10 1 B 28.6 108.1 9 C 27.9 33.6 15 D 27.4 31.5 >17 minutes 2 E 28.2 60.4 84 F 51.0 86.0 632 1 G 28.7 145.3 15 H 53.9 219.5 15 1 I 59.5 102.1 19 1 J 29.4 80.4 15 K 27.6 58.9 325 L 27.6 58.8 507 Comments: 1) Ambient temperature readings were much higher than actual ambient, client agreed to proceed with testing despite this difference. 2) Temperature appears to still be rising at the end of the data capture window.

REPORT # 24512323 Calorimeter Data Records

Test Number: 24512323 Date and Time:

Trial Number: 190916-9006 9/16/2019 DAS Operator: Joe Duffy 2:10:00 PM Calorimeter Avg Start Temp (°C) Max Temp (°C) Time to max heat (sec) Comments A 28.6 378.8 4 B 28.7 135.4 34 Comments:

REPORT # 24512323 Calorimeter Data Records

Test Number: 24512323 Date and Time:

Trial Number: 190917-9001 9/17/2019 DAS Operator: Joe Duffy 10:03:00 AM Calorimeter Avg Start Temp (°C) Max Temp (°C) Time to max heat (sec) Comments A 26.6 402.3 2 B N/A N/A N/A 1 Comments: 1) Calorimeter B was not available for this test. Prior to test, it was discovered that thermocouple was reading as an open circuit. It was confirmed in the test cell that the issue was with the thermocouple wire, and not the data system. Client agreed to proceed with the test without calorimeter B due to the time it would take to replace the thermocouple wire.

REPORT # 24512323 Calorimeter Data Records

Test Number: 24512323 Date and Time:

Trial Number: 190917-9002 9/17/2019 DAS Operator: Joe Duffy 3:35:00 PM Calorimeter Avg Start Temp (°C) Max Temp (°C) Time to max heat (sec) Comments A 25.9 227.5 6 B 25.5 480.4 8 Comments:

REPORT # 24512323 Calorimeter Data Records

Test Number: 24512323 Date and Time:

Trial Number: 190918-9001 9/18/2019 DAS Operator: Joe Duffy 9:20:00 AM Calorimeter Avg Start Temp (°C) Max Temp (°C) Time to max heat (sec) Comments A 22.2 155.1 6 B 28.7 >836 5 1 Comments: 1) Maximum temperature that can be recorded by thermal data system is 836° C.

REPORT # 24512323 Calorimeter Data Records

Test Number: 24512323 Date and Time:

Trial Number: 190918-9002 9/18/2019 DAS Operator: Joe Duffy 10:04:00 AM Calorimeter Avg Start Temp (°C) Max Temp (°C) Time to max heat (sec) Comments A 22.5 281.0 9 B 23.2 388.7 32 Comments:

REPORT # 24512323 Calorimeter Data Records

Test Number: 24512323 Date and Time:

Trial Number: 190918-9003 9/18/2019 DAS Operator: Joe Duffy 2:49:00 PM Calorimeter Avg Start Temp (°C) Max Temp (°C) Time to max heat (sec) Comments A 22.9 106.4 8 B 22.8 405.7 4 Comments:

REPORT # 24512323 Calorimeter Data Records

KEMA-Powertest, Inc.

Instrumentation Information Sheet TEST NO: 24512323 DATE: 09/19/2019 TEST DEVICE: Medium & Low Voltage Switchgear TESTED BY: J. Duffy, B. Swartz CALIBRATION CODE# TYPE MANUFACTURER MODEL# SERIAL# LAST DUE DAS20 DAS NI/DEWETRON DEWE-30-16 V08X02F33 10/16/2019 5/3/2020 PAV37 PNL.VOLTMTR SIMPSON F45-1-34 N/A 6/17/2019 1/3/2020 PAV24 PNL.VOLTMTR WESTON 1234 N/A 6/17/2019 1/3/2020 ISO141 ISO AMP DEWETRON HIS-LV 504659 10/16/2019 5/3/2020 ISO142 ISO AMP DEWETRON HIS-LV 504660 10/16/2019 5/3/2020 ISO143 ISO AMP DEWETRON HIS-LV 504661 10/16/2019 5/3/2020 ISO144 ISO AMP DEWETRON HIS-LV 504662 10/16/2019 5/3/2020 ISO145 ISO AMP DEWETRON HIS-LV 508022 10/16/2019 5/3/2020 ISO146 ISO AMP DEWETRON HIS-LV 508021 10/16/2019 5/3/2020 ISO147 ISO AMP DEWETRON HIS-LV 508020 10/16/2019 5/3/2020 ISO149 ISO AMP DEWETRON HIS-LV 416717 10/16/2019 5/3/2020 ISO150 ISO AMP DEWETRON HIS-LV 416728 10/16/2019 5/3/2020 ISO151 ISO AMP DEWETRON HIS-LV 416698 10/16/2019 5/3/2020 CTX15 C.T. ITE TR 56571 1/17/2019 1/17/2021 CTX16 C.T. ITE TR 56573 1/17/2019 1/17/2021 CTX17 C.T. ITE TR 56572 1/17/2019 1/17/2021 CTX214 ROGOWSKI CT PEM CWT75LFxB 37226-29255 10/16/2019 5/3/2020 CTX215 ROGOWSKI CT PEM CWT75LFxB 37226-29256 10/16/2019 5/3/2020 CTX216 ROGOWSKI CT PEM CWT75LFxB 37226-29257 10/16/2019 5/3/2020 CTS51 CT SHUNT DALE NH-250 N/A 7/8/2019 1/24/2020 CTS52 CT SHUNT DALE NH-250 N/A 7/8/2019 1/24/2020 CTS53 CT SHUNT DALE NH-250 N/A 7/8/2019 1/24/2020 VDR38 RES.VOL.DIV POWERTEST 189:1 38 7/8/2019 1/24/2020 VDR39 RES.VOL.DIV POWERTEST 189:1 39 7/8/2019 1/24/2020 VDR40 RES.VOL.DIV POWERTEST 189:1 40 7/8/2019 1/24/2020 VDR92 V.DIVIDER NORTH STAR PVM-11 1716317 6/21/2019 1/7/2020 VDR93 V.DIVIDER NORTH STAR PVM-11 1716417 10/16/2019 5/3/2020 VDR94 V.DIVIDER NORTH STAR PVM-11 1716517 10/16/2019 5/3/2020 KPT101 PRESS.TRANS OMEGA PX329 030318I148 7/16/2019 2/1/2020 KPT102 PRESS.TRANS OMEGA PX329 030318I131 7/16/2019 2/1/2020 AMP41 FO ISO AMP AAA LAB SYST AFL-300 1 8/12/2019 2/28/2020 AMP43 FO ISO AMP AAA LAB SYST AFL-300 3 8/12/2019 2/28/2020 AMP44 FO ISO AMP AAA LAB SYST AFL-300 4 8/12/2019 2/28/2020 AMP45 FO ISO AMP AAA LAB SYST AFL-300 5 8/12/2019 2/28/2020 KPT87 PRES.TRANS. OMEGA PX329 072613I064 10/24/2019 5/11/2020 KPT98 PRESS.TRANS OMEGA PX329 071114I076 4/5/2019 10/22/2019 REPORT # 24512323 Instrumentation Information Sheet

KEMA-Powertest, Inc.

Instrumentation Information Sheet TEST NO: 24512323* DATE: 09/19/2019 TEST DEVICE: Low & Medium Voltage Switchgear TESTED BY: J. Duffy, B. Swartz CALIBRATION CODE# TYPE MANUFACTURER MODEL# SERIAL# LAST DUE TEM89 TEMP.LOGGER DEWESoft KRYPTONi D05980d869 5/30/2019 12/16/2019 TEM92 TEMP.LOGGER DEWESoft KRYPTONi D05980F2EB 5/30/2019 12/16/2019 DAS17 DAS NI/DEWETRON DEWE-30-16 0195BB69 9/23/2019 4/10/2020 ISO132 ISO AMP DEWETRON HIS-LV 437726 9/23/2019 4/10/2020 ISO117 ISO AMP DEWETRON HIS-LV 437711 9/23/2019 4/10/2020 ISO118 ISO AMP DEWETRON HIS-LV 437712 9/23/2019 4/10/2020 ISO119 ISO AMP DEWETRON HIS-LV 437713 9/23/2019 4/10/2020 ISO124 ISO AMP DEWETRON HIS-LV 437718 9/23/2019 4/10/2020 ISO125 ISO AMP DEWETRON HIS-LV 437719 9/23/2019 4/10/2020 ISO126 ISO AMP DEWETRON HIS-LV 437720 9/23/2019 4/10/2020 CTX172 ROGOWSKI CT PEM SDS0680 0002-0100A 10/11/2019 4/28/2020 CTX173 ROGOWSKI CT PEM SDS0680 0002-0100B 10/11/2019 4/28/2020 CTX174 ROGOWSKI CT PEM SDS0680 0002-0100C 10/11/2019 4/28/2020 CTX175 ROGOWSKI CT PEM SDS0680 0002-0100D 10/11/2019 4/28/2020 VDR84 V.DIVIDER NORTH STAR VD-150 1 6/21/2019 1/7/2020 VDR86 V.DIVIDER NORTH STAR VD-150 3 6/21/2019 1/7/2020 VDR90 V.DIVIDER NORTH STAR VD-150 7 6/21/2019 1/7/2020 REPORT # 24512323 Instrumentation Information Sheet

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