scope:

This guide recommends procedures to be used to perform failure investigations of power circuit breakers. Although the procedure may be used for any circuit breaker, it is mainly focused on high-voltage ac power circuit breakers used on utility systems.

Recommendations are also made for monitoring circuit breaker functions as a means of diagnosing their suitability for service condition.

Purpose

The purpose of this guide is

a) to provide a methodology by which the most probable cause of any particular circuit breaker failure may be determined;

b) to provide sufficient guidelines and promote uniformity in the analysis of circuit breaker failures;

c) to provide guidance for systematic and uniform data collection so that valuable facts are not lost or destroyed;

d) to encourage cooperative efforts by users and manufacturers during failure analysis;

e) to encourage consistency of nomenclature and compatibility with similar efforts by other organizations such as CIGRE (International Conference on Large Voltage Electric Systems), EEl (Edison Electric Institute), IEC (International Electrotechnical Commission), NEMA (National Electrical Manufacturers Association), and AEIC (Association of Edison Alluminating Companies).