Friday, November 23, 2012
Index »
Circuit
»
Circuit Breakers Applying Interrupting Rating
A fully rated system is one in which all of the overcurrent protective devices
have an individual interrupting rating equal to or greater than the available
short-circuit current at their line terminals per 110.9. Fully rated systems can
consist of all fuses, all circuit breakers, or a combination of fuses and circuit
breakers. The interrupting rating of a branch circuit fuse is required by 240.60
to be marked on the fuse (unless its interrupting rating is 10,000A). The
interrupting rating of a branch circuit circuit breaker is required by 240.83 to be
marked on the circuit breaker (unless its interrupting rating is 5000A).
In this section, “individual” or “stand-alone” interrupting rating is used to denote the interrupting rating of a circuit breaker or fuse. It is the “individual” or “stand- alone” interrupting rating that is marked on a fuse or circuit breaker. See Figure 1. A major advantage with modern current-limiting fuses is that they have interrupting ratings of 200,000A or 300,000A. download here
Circuit Breakers Applying Interrupting Rating
In this section, “individual” or “stand-alone” interrupting rating is used to denote the interrupting rating of a circuit breaker or fuse. It is the “individual” or “stand- alone” interrupting rating that is marked on a fuse or circuit breaker. See Figure 1. A major advantage with modern current-limiting fuses is that they have interrupting ratings of 200,000A or 300,000A. download here