A switch mechanism such as a circuit breaker includes a trip indicator mechanism. The switch mechanism includes a switch contact and a rocker movable between a first position in which the contacts are closed, a second position indicating that an electrical fault has occurred, in which the contacts are open, and a third position in which the switch mechanism has been reset and the contacts are open. The rocker preferably comprises two rocker members (16, 18) hinged together with one of the rocker members (16) having a step formation between a front face and an end face. The step formation carries an instruction regarding resetting of the mechanism and lies substantially flush with the front panel (14) of the circuit breaker housing, with the face of the first rocker member standing partially proud of the front panel, when the rocker is in the second position. The mechanism allows a user to distinguish between manual switching off of the circuit breaker and tripping due to a fault.