Circuit breaker responsive to repeated in-rush currents produced by a sputtering arc fault

摘要

A circuit breaker responds to sputtering arc faults by counting the times that a bandwidth limited di/dt signal exceeds a threshold magnitude within a selected time interval. In the exemplary circuit breaker, if the threshold is exceeded twice within a one second interval, a trip solenoid is energized. The di/dt sensor can share a sensing coil with a ground fault detector. Alternatively, the resistance of the neutral lead within the circuit breaker is utilized to sense current which is converted to a bandwidth limited di/dt signal for level detection and counting of sputtering arc events.