Single-pole short-circuit interruption of molded-case circuitbreakers

摘要

Short-circuit tests of individual poles of molded-case circuitbreakers are required under North American industry standards. Testcurrent is intentionally at a limited fault availability level ratherthan at the interrupting rating of the circuit breaker. This paperclarifies the single-pole test requirements. It then examines thepotential fault conditions under a variety of systems and providesapplication guidelines considering the potential fault conditions