GFCI or Ground Fault Circuit Interrupters are an important safety device in a modern homes electrical system. Testing GFCIs to ensure they are in working order is an important part of the home inspection. The home inspector will use a simple testing tool to check the GFCIs for proper operation.
A GFCI can be thought of as a smart outlet or circuit breaker. It monitors the flow of current from the hot side of the circuit to the neutral. A difference in the amount of current could be current flowing somewhere it should not, such as into a wet hand touching a light switch. In as little as 1/40 of a second, the GFCI will trip, disconnecting the circuit and preventing a harmful shock.
GFCIs are required in all wet locations, such as outdoors, kitchens, baths and garages. Consumers will be most familiar with the outlet style GFCIs, with integrated test and reset buttons. It is common to find these in kitchens and baths. An outlet type GFCI may be wired as the first outlet on a circuit and will then protect each outlet wired “downstream” from that outlet. It is common to find multiple kitchen and bath outlets on the same GFCI circuit, so if you have a dead outlet in one of those locations, it is likely due to a tripped GFCI somewhere else in the kitchen, or in a bath, in another location entirely. Very often during a home inspection, I find a single GFCI outlet in a first floor powder room that serves every bathroom in the home. This can be quite a nuisance to the homeowner and I always point it out during a home inspection.
A less familiar form of GFCI is found in the main breaker panel. Breaker type GFCIs work in much the same way as outlet type, but are integrated into a circuit breaker. The test button will be found on the breaker itself, and will protect the entire circuit.
Whichever type is found in your home, it’s a good idea to test them periodically. Older GFCIS can become frozen and fail to trip, or once tripped, fail to reset. If you find either condition in your home, have the GFCI replaced by qualified electrician. For more information on GFCIs, visit OSHA.