ML19296B763

Significant Deficiency Rept 369-370/79-13:investigation of Cable Connection Failure Revealed Improper Insulation Stripping by Nelson Electric Co,Possibly Resulting in Equipment Failure.All Related Equipment Will Be Inspected

ML19296B763
Person / Time
Site:	Mcguire, McGuire
Issue date:	01/10/1980
From:	DUKE POWER CO.
To:
Shared Package
ML19296B761	List: ML19296B759 ML19296B763
References
NUDOCS 8002210481
Download: ML19296B763 (1)

Text

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. . .b DUKE POWER COMPANY McGuire Nuclear Station Report No.: SD 369-370/79-13 Report Date: January 10, 1980 Facility: McGuire Nuclear Station - Units 1 and 2 Identification of Deficiency: Faulty Connections in Electrical Equipment ,

Description of Deficiency:

An investigation was conducted as a consequence of the failure of a cable It connection inside a starter of a safety-related motor control center.

was found that the failure was due to improper stripping of insulation on Comolete inspection the cables by the manufacturer, Nelson Electric Company.

of the motor control center involved in the incident revealed that six of 309 connections inside this center were potential sources of problems due to improper insulation stripping of cable. In addition to motor control centers other equipment supplied by Nelson Electric. includes panel boards, distri-bution centers and remote starters.

Analysis of Safety Implications:

The improper stripping back of insulation on cables prior to making up a bolted connection of a cable to a power device inside the starter (breaker or contactor) would result in excessive heating of the cable and could result in eventual failure of the cable. Such a cable failure would result in loss of function of the equipment in the circuit of the failed cable. The equip-ment potentially involved includes fan, punp, and valve motors, inverters, batteries, heaters, transformers, and cranes.

Preliminary investigation indicates that this problem is random, that the number of faulty connections is relatively small, and that there is small probability of redundant equipment being affected.

Corrective Action:

All Nelson Electric distribution centers, panel boards, starters, and motor control centers at McGuire Units 1 and 2 vill be inspected to detect any possible problems similar to the one described herein. Inspection of all equipment identified above in Unit 1 is scheduled to be completed by June 1, 1980. Inspection of all Unit 2 equipment is scheduled to be completed by December 31, 1980. Correction of any deficient connections will be accomplished on this same schedule. ,

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