Circuit breakers are the functional combination of a fuse and a switch. They have the
advantage over a fuse of being able to be reset. When the current rating of a circuit
breaker is exceeded, a switch is automatically opened which breaks the circuit. The
switch can be manually actuated, and the circuit breaker reset to again perform its function.
It does need not be replaced after functioning as a fuse does. Circuit breakers are
designed with one of two actuating mechanisms; thermal and magnetic.