Abstract: A circuit breaker includes a main case; a switching mechanism accommodated in the main case, and having a mechanical part for opening and closing a circuit; a trip mechanism configured to trigger the switching mechanism to a circuit interrupting position upon detection of an abnormal current on a circuit; and an external device detachably mounted to the main case, wherein the circuit breaker includes an interrupting means configured to interrupt the switching mechanism by contacting at least a part of the external device when the external device is mounted to the main case.

Abstract: A circuit breaker includes a main case; a switching mechanism accommodated in the main case, and having a mechanical part for opening and closing a circuit; a trip mechanism configured to trigger the switching mechanism to a circuit interrupting position upon detection of an abnormal current on a circuit; and an external device detachably mounted to the main case, wherein the circuit breaker includes an interrupting means configured to interrupt the switching mechanism by contacting at least a part of the external device when the external device is mounted to the main case.

Abstract: A bimetal assembly includes: a heater connected to a movable contact to be provided with power; and a bimetal having one end portion coupled to the heater and disposed to be spaced apart from the heater, wherein the heater includes: a coupling portion coupled to the bimetal; a separation portion spaced apart by a certain distance from the bimetal; and a connection portion connecting the coupling portion and the separation portion, wherein at least one projection is formed to be protruded from the separation portion toward the bimetal.