Input Protection Diodes Functioning with Circuit Breaker?
There is a mechanism that kicks the circuit breaker into action, and it relies on current (not voltage) in the traditional circuit breaker. When the current reaches a certain level a coil triggers the spring loaded switch to turn off. Some breakers also have a bimetallic that triggers when it gets to hot in response to current. 


Source: https://electronics.howstuffworks.com/circuit-breaker2.htm