A circuit breaker module (which may also be termed an interrupter) including circuit breaker contacts which are opened and closed by an electrically-activated magnetic actuator and capable of interrupting fault currents. The magnetic actuator is stable in either a breaker-closed state or a breaker-open state without requiring electrical current flow through the magnetic actuator. An externally-connectable mechanical drive is linked to the magnetic actuator in a manner such that movement of the externally-connectable mechanical drive can destabilize the breaker-closed state to open the circuit breaker contacts. An external actuator activated by an external condition is connected to said externally-connectable mechanical drive so as to cause said circuit breaker contacts to open upon occurrence of the external condition.