The circuit breaker according to the present invention comprises: a pair of contact mechanisms for switching a pair of circuits; a switching mechanism for driving the pair of contact mechanism to a circuit opening position or a circuit closing position; a trip bar rotatable to a first position for latching the switching mechanism or to a second position for releasing the switching mechanism; and an instant trip mechanism for pressing the trip bar to rotate to the second position, wherein the instant trip mechanism comprises a pair of armature assemblies and movable to a position for pressing the trip bar to rotate to the second position; and a pair of electromagnets provided to face the pair of armature assemblies and applies a magnetic attractive force to the pair of armature assemblies in response to the fault current on the circuit requiring an instant trip.

The circuit breaker according to the present invention comprises: a pair of contact mechanisms for switching a pair of circuits; a switching mechanism for driving the pair of contact mechanism to a circuit opening position or a circuit closing position; a trip bar rotatable to a first position for latching the switching mechanism or to a second position for releasing the switching mechanism; and an instant trip mechanism for pressing the trip bar to rotate to the second position, wherein the instant trip mechanism comprises a pair of armature assemblies and movable to a position for pressing the trip bar to rotate to the second position; and a pair of electromagnets provided to face the pair of armature assemblies and applies a magnetic attractive force to the pair of armature assemblies in response to the fault current on the circuit requiring an instant trip.

An overload protection device is disclosed, characterized in that, the overload protection device comprises a first heating band (i.e., a terminal); a second heating band; a bimetallic strip; a litzendraht wire; a lower part of the first heating band and a lower part of the bimetallic strip are mechanically connected with each other; two ends of the litzendraht wire mechanically connect with an upper part of the second heating band and an upper part of the bimetallic strip respectively.

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 including an adjustable instantaneous trip level. Adjustable instantaneous trip level can be applied to a one-pole and/or two-pole circuit breakers including a thermal and magnetic mechanism, including AFCI, CAFCI, and/or GFCI constructions. The circuit breaker includes a magnet position adjustment mechanism allowing an operator to adjust the instantaneous trip level to a desired setting, such as between about 5 to 10 times the handle rating. The design also allows for alternate magnets to be used for either an increased or decreased instantaneous settings as desired. In two-pole circuit breakers, the instantaneous trip level can be set independently for each mechanism pole. Multi-pole circuit breakers and methods of adjusting instantaneous trip level are provided, as are other aspects.