Circuit interrupter protective device

Claim 1

A circuit interrupter protective device for responding to abnormal currents in the conductors of an electrical distribution system and for actuating a circuit interrupter to open upon the occurrence of predetermined operating conditions, comprising a circuit breaker having a first insulating housing, a circuit breaker mechanism within the housing and comprising separable contacts adapted to be connected as part of the distribution system, a trip member within the housing and being movable to effect opening of the contacts, a current monitoring transformer for each conductor of the distribution system, a trip actuator comprising an actuating coil and being operable to actuate the trip membEr, solid-state static sensoring means connected to the current monitoring transformers and responsive to a signal from any of the transformers to pulse the actuating coil of the trip actuator, a second insulating housing containing the solid-state sensoring means, the second insulating housing being mounted within the first insulating housing, the second insulating housing comprises an open side formed by the two housing members, a third housing closure member closing the open side and having interfitting edge and end portions engageable with corresponding edge and end portions of the two housing members, the third housing closure being retained in place against displacement by the peripheral portions of the opposite end and side walls when the two housing portions are assembled, and the third housing closure being removable from the open side only when the two housing portions are disassembled.