Circuit breaker with a single test button mechanism

Conventional residential, light industrial and commercial circuit breakers typically have a thermal trip mechanism which responds to persistent overcurrents of moderate magnitude to provide a delayed trip in the breaker. Also included in the circuit breaker is a magnetic trip mechanism which responds instantaneously to overcurrent conditions of greater magnitudes. It is becoming more common for these circuit breakers to further include a ground fault trip mechanism as one of the active mechanisms. The ground fault trip mechanism includes a trip unit which detects faults between the line conductor and ground and the neutral conductor and ground. Line to ground faults are commonly detected by the use of a differential transformer. The line and neutral conductors are passed through the coil so that in the absence of a line to ground fault, the currents are equal and opposite and no signal is generated. However, when a line to ground fault exists, it creates a sizeable imbalance between the two currents in the two conductors which can be level detected. As is known, a neutral to ground fault may be detected by injecting a signal onto the neutral conductor which will produce an oscillation if feedback is provided. In an exemplary embodiment of the invention, a dual test mechanism is presented for use in a circuit breaker. More specifically, the dual test mechanism includes a dual test button which comprises a single switch for testing both the AFCI and GFCI circuits of the breaker. The test mechanism includes a circuit board, which forms a part of the circuit breaker, and a test button assembly which includes a test button and signaling components which are electrically connected to the circuit board.