Patent ID: 8766749

Claim:
A miniature circuit breaker comprising: a pair of openable contacts located in a main current path between a line terminal and a load terminal; a trip mechanism for opening the contacts if an overcurrent condition occurs; and an electric motor operable to close the contacts via a contact closing mechanism; wherein the trip mechanism includes: a trigger mechanism and a contact opening mechanism, the trigger mechanism being arranged to trigger the contact opening mechanism into opening the contacts if a trip signal is produced; a current sensor arranged to detect current through the main current path; and a control unit; wherein the control unit is: arranged to produce the trip signal to operate the trigger mechanism to trigger the trip mechanism into opening the contacts if it determines that a short circuit condition occurs based on an output of the current sensor; and is further arranged to operate the electric motor to trigger the contact opening mechanism into opening the contacts independently of the trigger mechanism if it determines that an overload condition occurs.