A branch circuit ... breaker) that opens all ungrounded conductors of the multiwire branch circuit simultaneously (common internal trip) under a fault condition. If the continuity of the grounded ...

This could be because the circuit breaker trips — interrupts the flow of electricity at specific circuits — to ensure the ...

Electrical current exceeding the breaker-overload rating heats the bimetal enough to bend it toward the trip bar. As the bimetal bends, it touches and rotates the trip bar to open the circuit.