ML20127G390

Forwards RO Bulletin 74-13, Improper Factory Wiring on GE Motor Control Ctrs at Ft Calhoun, for Licensee Response

ML20127G390
Person / Time
Site:	Monticello, Prairie Island
Issue date:	10/25/1974
From:	James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
To:	Wachter L NORTHERN STATES POWER CO.
References
IEB-74-13, NUDOCS 9211160579
Download: ML20127G390 (1)

Text

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I ATOMIC ENERGY COMMISSION 3, y7^y['*

DIRECTORATE OF REGULATORY OPERATIONS V

REGION lil

1. '8 til 4' 799 ROOSEVELT ROAD ggggpwoyg GLEN ELLYN. ILLINOIS 60137 012)S56-2660 Detober 25, 1974 Northern States Power Campany Docket No. 50-263 ATIN: Mr. Lee Wethter, Vice President Docket No. 50-282 Power Fredestica and Systes Docket No. 50-306 Operation 414 Nicollet Mall Ninaampolis, Mianosota 55401 Goatlemen The enclosed 30 Bulletin requeste actions by you with regard to your reactor faailities with operating license or construction permit.

Should you have questions regarding this Bulletin or actions requested of you, please senteet this office.

Sincerely yours, James G. Kappler Regional Director Enclosurst RD Bu11stia 74-13 bcct,DR Central Files RO Files PDR Local PDR OGC, Beth, P-506A Anthony Roisman, Esq.

9211160579 741025 PDR ADOCK 05000263 G

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October 25.-1974 R0 Bulletin No. 74-13 i

IMPORPER FACTORY WIRING ON GENERAL PLECTRIC MOTOR CONTROL CENTERS i

AT FORT CALHOUN We recently received 1iformation from Omaha.Public Power District j

describing a deficiency in the factory wiring on GE type 7700 MCC j

breaker-starters. The imprope-41 ring was discovered in both safety related and non-safety relatr.d 'areaker-starters at the Fort Calhoun nuclear power plant.

1 Description of Circumstances l

OPPD reported the insulation on the power carrying wires in the l

combination breaker-starter for the non-safety related demineralized water transfer pump burned due to over-current and improper factory l

wiring practices. The-improper factory wiring was discovered while j

OPPD pe,rsonnel were rewiring the breaker-starter (GE type 7700 MCC, l

THEF-100A, 3 phase, 480 V, FVNR Size 3).

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The factory installed wire was CE Vulkene "600" Cable Type XHHW -

l SI-58053 B 4AWG 600 V (UL). The wire is made of. stranded copper l

conductors covered by cellophane tape which in turn is covered j

by an outer cable jacket. In the affected. breaker-starter,-the cellophane tape had not been removed after the cabic jacket was l

stripped off; therefore, the lug was crimped directly over the l

cillophane resulting in a limited contact surface between the conductor and the lug. When the motor overloaded, due to worn bearings, excessive heating occurred at the lug-cellophane-conductor interface causing the cable jacket to burn and the molded case circuit breaker to be deformed.

F Inspection of all CE MCC-switchgear revealed 13 out of 20 CE MCC's l

wired with GE Vulkene "600", Cable Type X1HIW, SI-58053 B 4 AWG were wired improperly. 'A similar-problem existed in.3 out of 11 j,

breakers where GE Vulkene "600", Cable Type XHHW, SI-58053 B 2 AWC j

wire was used. The problem was found to be characteristic of the

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cable type and wire size rather than the breaker-starter size, i

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OPPD reported that the problem has been discussed with GE and that j

GE plans to replace the wire in the affected breaker-starters at l

Fort Calhoun.

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RO Bulletin No. 74-13 October 25, 1974 Action Requested of Licensees It is requested that you review the use of GE Vulkene "600" cable in safety related breaker-starters of your facilities, and provide the following information to this office in writing within 60 days:

Where GE Vulkene "600" cables of the breaker-starters type described above have been used in safety related breaker-starters of your facilities, describe the action you have taken or plan to take to insure against improper termination of these cables similar to that described above.

Your wTitten reply to this Bulletin should include a description of the number and location of any cables found to be improperly terminated, together with the date corrective measures were, or will be, completed.

if GE Vulkene "600" cables of the type breaker-starters described above have not been used in safety related breaker-starters of your facilities, your written response should indicate this to be the case.

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