Circuit breakers are safety devices that shut off the electricity if there is trouble in a branch circuit. They are designed to protect wires from being overloaded and starting fires. They operate on temperature, building up enough heat until a circuit breaker trips. If a circuit breaker does not trip, you should let it cool, then flip it all the way off and back on again. Never flip the large breakers (30 Amps and above) off and on until you are sure that the air conditioning is not on, you could damage the air conditioning compressor if it is running.