Siemens Speedfax™ BQ1M040 Molded Case Circuit Breaker, 120 VAC, 40 A, 10 kA Interrupt, 1 Pole, Thermal Magnetic Trip

Circuit breakers provide a manual means of energizing and de-energizing a circuit. In addition, circuit breakers provide automatic over current protection of a circuit. A circuit breaker allows a circuit to be reactivated quickly after a short circuit or overload is cleared. Unlike fuses, which must be replaced when they open, a simple flip of the breaker's operating handle restores the circuit.