Short circuit ratings, labels and fault withstandability of molded-case and insulated-case circuit breakers and combination motor starters

摘要

Short-circuit ratings, labels, and fault withstandability of molded-case and insulated-case circuit breakers and combination motor starters are discussed. Problems can arise when applying electrical equipment without understanding the test methods used to determine the equipment's short-circuit current interrupting ratings. The present testing and rating methods used for low-voltage circuit breakers and combination motor starters must be understood and applied to ensure the safest possible application. The major concern with the testing described is that the test set-up includes some length of rated wire that does not exist in many of industry's applications.