ML20125A879

Final Deficiency Rept Re Defective Type SB12 Auxiliary Switches on GE Metalclad Switchgear.Qc Hold Tags Placed on All Switches.Defective Switches Will Be Replaced by GE When Proper Switches Are Available

ML20125A879
Person / Time
Site:	Callaway
Issue date:	08/10/1979
From:	UNION ELECTRIC CO.
To:
Shared Package
ML20125A874	List: ML20125A871 ML20125A879
References
NUDOCS 7908200294
Download: ML20125A879 (6)

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Report

. on Defective Type SB12 Auxiliary Switches on General Electric Metalciad Switchgear, s

7908200 29 p

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-i-Table of Contents I. Introduction II. Material Description III. Material Deficiency and Safety Implications IV. Investigation at the Callaway Jobsite ,

V. Corrective Actilon I .

Attachments A. Summary of Callaway Jobsite Class IE Type SB12 Auxiliary Switches l

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I. Introduction In accordance with the requirements of 10 CFR 50.55e, this final report is submitted relative to the deficiency in General Electric Type SB12 auxiliary switches.

General F.lectric advised us by letter dated July 6,1979, of a potential 10 CFR 21 incident related to auxiliary switches used in metalclad switchgear. Action was immediately taken to determine if defective switches were in existence at the Callaway jobsite. General Electric was advised by Bechtel that the defective switches constituted a reportable deficiency and they were requested to take corrective action. General Electric subsequently instructed their local Installation and Service Engineering Division representative to coordinate an inspection and replacement program.

II. Material Description Type SB12 auxiliary switches form an integral part of the circuit breaker trip coil circuit. The trip coil and switch "a" contacts are monitored on the front door of the switchgear by a red light which is illuminated when the breaker is closed. The illuminated red light signifies trip circuit continuity and that a trip signal will open the hreaker.

In addition, Type SB12 auxiliary switches are provided as stationary contacts in the switchgear cubicle for interlocking and annunciation.

III. Material Deficiency and Safety Implications Factory tests by General Electric revealed that some Type SB12 switches on circuit breakers were found to have intermittent con-tinuity through the switch "a" contacts in the trip coil circuit.

Investigation by General Electric revealed that a die used to form a hole in the contact arms of the switch had worn resulting in elongated holes. This condition could permit the contact bridge member to move laterally relative to the contact arm resulting in occasionally improper contact wipe.

Failure of this auxiliary switch contact to close prevents electrical tripping of the circuit breaker, and, if undetected, the ability to provide reliable pcwer to Class IE loads could be significantly degraded.

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. s IV. Investigation at the Callaway Jobsite

- An inspection program was undertaken at the Callaway jobsite to identify Type SB12 switches in the 4.16KV Class IE metalclad switchgear supplied by General Electric. The identification was performed using the Quality Control Acceptance Number on each switch.

This QC number consists of a date code which is unique to the date of switch manufacture. The results of this inspection are contained in Attachment A. This information has been communicated to i General Electric. .

! It was determined by GE that all Type SB12 switches in Class IE applications at the Callaway jobsite with the exceptio'n of those I with QC Acceptance Number 30FM were defective.

. V. Corrective Action i Nonconformance report No. 2SN-0822-E was issued on July 17, 1979, to I document the Type SB12 auxiliary switches that have been received

- at the Callaway jobsite. "QC Hold" tags have been placed on all

Type SB12 switches. GE will replace the defective switches when i replacements become available.

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6 I Pcgo 1 Attachment A Summary of Callaway Jobsite Class IE Type SB12 Auxiliary Switches General Electric Quality Control Circuit Breaker Drawing Number Acceptance No.

Serial Number 226A9287-G1 31AR 269A5311 - 011

• 31AR ,

- 012

- 001

• 31ER

" 31ER

- 002

• 31ER

- 003

- 004

• 31ER -

" 31ER

- 005 " 31ER

- 006

- 007

• 31ER

• 31ER

- 008 " 31ER

- 009

- 010

• 31ER

- 015

" 31ER

"- 31ER 269A6000 - 001 " 31ER

- 020 General Electric Quality Control Metalclad Switchgear Acceptance No.

Equipment Number Drawing Number 6353570-G12 30PM NB0101 " 30JM 02

• 30JM 03 " 30JM

.04 " 30JM 05 " 30JM

.06 " 30JM 07 " 30FM 08 " 30FM 09 " 30JM 10 " 30JM 11 " 30JM 12

• 30JM 13 " 30JM 14 " 30HM 15

• 30RM 16 " 30JM 17

• 30HM NB0201

• 30JM 02 " 30HM 03 " 30HM 04 " 30HM 05

• 30HM 06

• 30JM 07

l Pcgo 2 Summary of Callaway Jobsite Class IE Type SB12 Auxiliary Switches (cont'd! l Metalclad Switchgear General Electric Quality Control Equipment Number Drawing Number A_cceptance No.

NB0208 6353570-G12 30HM 09

" 30JM l

" 30HM 10 11

" 30JM

" 30HM 12

• 30HM 13 " '

14 30HM

" 30HM 15

" 30HM 16 17

" 30HM, O

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