Let’s look at a few of the differences between thermal and magnetic breakers. First, by the nature of their design, thermal breakers are temperature sensitive while magnetic breakers typically are not. Thermal breakers are not voltage sensitive and the same thermal breaker may be used for either AC or DC voltage. In contrast, magnetic breakers are voltage sensitive and different part numbers are required for AC and DC applications. Also, thermal breakers are offered with a set range of delay time before tripping at given over-current values while magnetic breakers can be built to provide various delays before tripping. This is useful when protecting a component such as a motor that might have a high inrush current that must be allowed before tripping. Additionally, Tyco Electronics offers 1- or 2- pole thermal breakers and magnetic breakers from 1-pole up through 4-poles.