circuit breakers
circuit breaker are a form of switch that opens when current passing through them exceeds some designed limit. There are two kinds of breakers, each with a different principle of operation. One type open when the temperature of the breaker reaches a predetermined level. The temperature of the environment around the breaker can affect is response, The second type is magnetic, which opens when a predetermined current level is reached. Environment temperature has less affect on this type of breaker. There are many different breaker designs. Codes specify what types to use in certain applications