Embodiments provide tripping unit of a circuit breaker. The tripping unit includes a magnet, a bimetal member extending alongside of the magnet, and an armature pivotable on the magnet, wherein the armature having an engagement portion engageable with the bimetal member at a moveable end of the bimetal member. Circuit breakers including triggering mechanisms and tripping units are also disclosed, as are low-profile, electronic circuit breakers including a maximum transverse width (Wt) limited to occupy only a single standard breaker panelboard location. System and methods are provided, as are other aspects.

A circuit breaker tripping mechanism providing relatively low instantaneous level tripping is disclosed. Circuit breaker tripping mechanism includes an armature with a first portion extending in a first direction from an armature pivot and a second portion extending in a second direction from the armature pivot, and a magnetic field generator configured as part of a line conductor. Magnetic field generator is operable to produce a magnetic field acting upon the second portion during a short circuit. Circuit breakers including the circuit breaker tripping mechanism and methods of tripping a circuit breaker are provided, as are other aspects.