A safety latch assembly for a circuit breaker panel board. The panel board includes a cabinet in which one or more circuit breakers are mounted behind a panel member, the breakers being operable between ON and OFF positions by an actuating member which in turn is operated by a handle mechanism mounted in the cover of the cabinet. The safety latch assembly includes a movable member operable in response to movement of the actuating member. The movable member has means engaging a portion of the handle mechanism preventing engagement of the actuating member by the handle mechanism, and thus preventing closing of the cabinet cover to which the handle mechanism is mounted, when the actuating member of the breaker is in the OFF position. Means are also provided for engaging the handle mechanism with the actuating member of the breaker in the ON position, preventing disengagement of the handle mechanism and the actuating member and removal of the cover.

A static trip, molded case circuit breaker includes an operating mechanism having powerful mechanism springs to achieve the requisite contact pressures for high current carrying capacity. A rotary handle resets the operating mechanism via a reciprocating slide and a latching mechanism, while loading the mechanism springs. Return of the handle to its original position achieves rapid closure of the circuit breaker contacts. The latching mechanism is equipped with a trip interlock operating to trip the circuit breaker in response to removal of the case cover and to thereafter disable resetting of the operating mechanism in the absence of the cover and/or electronic trip unit.

Switch apparatus is disclosed. The switch apparatus has an enclosure, having a openable cover, a switch disposed within the enclosure, a handle in operative communication with the switch, a spring in biasing communication with the handle, and interlocking members. The interlocking members, the handle, the biasing spring and the switch having positions relative to each other such that the interlocking members lock the cover in a closed position in response to the handle being biased toward an OFF position, and the switch contacts being closed. Further disclosed is a method for unlocking a closed cover of a switch apparatus. A spring biased handle is changed to an OFF biased position from an ON biased position passing through a non-biased position. Subsequent thereto, a switch being changed from a closed circuit to an open circuit position. Subsequent thereto, interlocking members are changed from an interlocked to a non-interlocked position.