A device such as a contactor, switch, or tripping device that is used to make or break a circuit under normal or fault conditions. An unwanted arc is often produced as the circuit-breaker operates and this can be minimized using a magnetic blow-out device. This device is fitted to the circuit-breaker and produces a magnetic field in the neighbourhood of the arc, thus causing the pathlength of the arc to increase and thereby extinguishing it rapidly. When used for fault conditions an automatic break and manual make system is commonly used.