How do you diagnose a faulty breaker?

Answer by  tracker76 (135)

Check if it trips with no load on the circuit (nothing plugged in, all lights off) and/or there is no voltage from the load terminal.

Answer by  fancbiz (952)

By trying a small overload and watching how it reacts to it. A faulty circuit breaker never trips at the time it is required to do so. It would be dangerous to induce a short circuit but a small controlled overload on the circuit breaker would give the required signs of good working.