Abstract: Multi-pole circuit breakers are joined together to form a common assembly. The individual poles are in the form of compact circuit breakers having a pair of separable contacts controlled by a single externally-accessible operating handle. The individual circuit breakers are riveted together and are keyed such that the contacts open and close in unison. The individual handles are interlocked together by means of a unitary plastic handle tie.

Abstract: A residential circuit breaker electromagnetic trip unit facilitates the assembly of the trip unit components by use of a pair of braid connectors for connection between the trip unit magnet and the circuit breaker contact arm. The trip unit bimetal is directly welded to the trip unit magnet and the braid connectors for reduction in material and labor costs. The contact arm and the magnet are shaped to present a parallel path connection between the contact arm and the magnet for close fit tolerance. The front surface of the magnet is configured to prevent magnetic adhesion between the magnet and the trip unit armature under intense short circuit overcurrent conditions.

Abstract: A modular plastic trip bar assembly joins separate single pole molded case circuit breakers into a single multipole circuit breaker. The addition of the trip cam to the trip bar assembly allows four and five pole combinations to operate in unison.

Abstract: A molded case circuit breaker for residential use employs an additional safety feature to ensure a fail-safe condition in the event that the circuit breaker is installed within a circuit that may be subjected to an excessive over-current fault that disables the circuit breaker trip unit. The integral bimetal-fuse within the circuit breaker trip unit responds to interrupt circuit current before any damage can occur to the associated electrical wiring system.

Abstract: A molded case thermal-magnetic circuit breaker having improved low current magnetic trip response pivotally arranges the magnet within the circuit breaker thermal-magnetic trip system for controllably moving toward the latching armature assembly. The movement of the magnet decreases the magnetic separation distance between the magnet and the latching armature to optimize the magnetic trip forces and thereby enhance low current magnetic trip response.

Abstract: A circuit breaker latch assembly eliminates the need for polishing the opposing latch surfaces to reduce static surface friction and lower the latching force. The end of the circuit breaker cradle operator is offset relative to the restraining surface of the armature-latch to reduce the static friction that must be overcome to move the armature-latch away from the cradle operator. Subsequent release of the cradle operator then allows the circuit breaker operating mechanism to separate the circuit breaker contacts upon the occurrence of predetermined overload current conditions.

Abstract: A molded case thermal-magnetic circuit breaker having improved low current magnetic trip response pivotally arranges the magnet within the circuit breaker thermal-magnetic trip system for controllably moving toward the latching armature assembly. The movement of the magnet decreases the magnetic separation distance between the magnet and the latching armature to optimize the magnetic trip forces and thereby enhance low current magnetic trip response.

Abstract: A molded case circuit interrupter of the type employing a thermal-magnetic trip unit to interrupt circuit current utilizes a flexible electrical braid conductor to connect between the thermal-magnetic trip unit and the movable contact arm. A helical spring arranged around the braid conductor at the welded connection with the movable contact arm provides long-term strain relief. A metal phosphate coating on the surface of the circuit breaker operating cradle and latch assembly eliminates polishing while insuring release of the cradle from the cradle-latch interface surfaces.