Abstract: A circuit breaker, notably breaking the phase and neutral circuit, contains a shunt circuit, constituted by a switching electrode disposed in proximity to the phase contacts to pick up an arc drawn between these contacts, when opening occurs on a short-circuit. Transferring the arc onto the switching electrode closes a shunt circuit, creating an internal short-circuit protecting the cables and receivers downstream from the circuit breaker. The shunt circuit is broken when the arc is blown out in the arc chute. Fast shifting of the arc protects the contact surfaces, notably of the neutral contacts, enabling these contacts to be used for an impulse relay or remote-controlled contactor function.

Abstract: The separation partition (44) of the arc formation chamber (38) from the mechanism of a miniature circuit breaker is formed so as to follow at least on a part of its length some equipotential lines generated between the separated contacts (20, 22) of the circuit breaker. This particular shape of the partition (44) increases the insulating level of the appliance after a fault elimination.