A circuit breaker is a thermally operated mechanical device that replaces the functions of a fuse and is today the most commonly used overload protection device. Once operated because of excess current, the device can be reset only once.

If a circuit breaker trips while you’re flying, it’s okay to reset it after allowing a minute or two for it to cool, even if you have no idea what caused it to trip and cut off electrical power to a particular circuit. Only if the breaker trips a second time should you not try to restore power by resetting it. Excessive resetting of the circuit and therefore allowing the potentially overcurrent to flow could damage systems and electrical damage could potentially become worse.