Abstract: A molded case circuit breaker comprising a case divided longitudinally into two approximate half cases. Each case defines an arcing chamber. Further, each half case has a side wall, an end wall, and a top wall. The end walls of each half case define an opening through which the arc gases are vented. The top walls of each half case define an inverted U-shaped cavity. A V-shaped screen has one leg thereof placed against the end walls to restrict the opening. The other leg of the V-shaped screen extends into the U-shaped cavity, but is spaced from the wall defining the U-shaped cavity. The V-shaped screen has legs which are spaced apart to provide a space through which the arc gases may pass. The circuit breaker also includes a stationary contact surrounded on all sides but one by an arc runner which is keyed to a supporting conductor.

Abstract: An electrical circuit breaker comprising an electromagnetic device including a linearly movable armature and a linearly movable time delay assembly. The time delay assembly has a forward end portion which carries a lever. The forward end portion includes a catch to latch the movable contact arm in the contacts "on" position. On predetermined electrical conditions, the armature moves linearly, engages the lever, which then pivots and engages the movable arm, moving the latter out of engagement with the catch, whereupon the contacts open. The contacts may be opened manually by rotating the time delay assembly, whereupon a portion of the assembly engages the movable arm and moves the latter out of engagement with the catch, and the contacts then also open. The contacts, in both instances, may be manually reclosed by moving the time delay assembly toward the contacts, if the electromagnetic device is no longer energized sufficiently to trip open the circuit breaker.