Comparing test requirements for low-voltage circuit breakers

The standards dealing with low-voltage power circuit breakers and molded case circuit breakers, have many common elements. As a consequence, either type of circuit breaker could be used for some applications. However, there are several significant performance differences that relate to the application of these circuit breakers, specifically, the low-voltage power circuit breaker is normally applied upstream of the molded case circuit breakers. That location frequently requires higher continuous currents, higher interruption ratings and a short-time current duty cycle capability for selective coordination.