Circuit breaker is a device which opens an electrical circuit when an excess of current flows. A circuit breaker may be reset to restore the circuit after the fault causing the excessive current has been corrected.

A、Circuit breaker is a device which opens an electrical circuit when an excess of voltage.
B、Circuit breaker can be reset after the fault fixed.
C、Circuit breaker is no more serviceable and needs to be replaced at once after an excess of current flows that causes it open