Abstract: A circuit breaker having electrical contacts operable between a closed position in which a circuit is completed through the conductor and an open position in which the circuit through the conductor is interrupted. The circuit breaker includes a latchable operating mechanism operable to open the electrical contacts when unlatched and a trip bar rotatable from a biased position to a trip position to unlatch the operating mechanism. A magnetic trip assembly is provided including a frame, a stationary magnetic structure mounted to the frame and a movable armature which is attracted to the stationary magnetic structure by abnormal current through the conductor to rotate the trip bar to a trip position. The movable armature includes a nib extending angularly therefrom, the nib defining a detent. The armature is pivotably mounted to the stationary magnetic frame by a pin.