Find out what the GFCI actually protects
The Consumer Product Safety Commission (CPSC) explains that a receptacle-type GFCI protects whatever is plugged into it and other outlets further "downstream" on the same branch circuit. Those downstream outlets look ordinary and have no buttons. The GFCI shuts off power when the current going out and coming back differ by as little as 0.006 amps, so a small leak in a single appliance two rooms away is enough.
Next time it trips, walk the house before you press reset and write down every outlet and fixture that lost power. Pay attention to things you forget are plugged in: a basement freezer, a sump pump, garage tools, holiday lights or a bathroom fan heater. Then unplug everything on those dead outlets, reset the GFCI, and plug items back in one at a time. If it trips right after one item goes back in, that item is your main suspect and should be checked or repaired before it's used again.
If you can't find the GFCI at all, start where the CPSC fact sheet says the electrical code has required them: outdoors (since 1973), bathrooms (1975), garages (1978), kitchens (1987), and unfinished basements and crawl spaces (1990). In older Philadelphia rowhomes the controlling GFCI is often in a bathroom or the basement, not next to the outlet that went dead.
Trips that follow rain point to moisture
If it only trips during or after rain, after hosing down the patio, or after a leak, moisture somewhere on the protected circuit is the likely cause. Outdoor outlets, garage outlets and basement outlets near a damp wall are the usual places. The CPSC's home electrical checklist says to keep electrical equipment away from water, including rain, leaks and spills, because the mix can cause a serious shock or fire.
Write down the dates of trips next to the weather. That pattern is useful information for an electrician, though it doesn't tell you which outlet is wet. Don't open outlet boxes to look, don't touch a wet outlet or plug, and don't try to dry one with a heat gun or hair dryer.
If nothing is plugged in anywhere, the GFCI may be failing
When all the downstream outlets are empty, everything is dry, and it still trips, the device itself or the wiring behind it is the next suspect. Don't guess by age alone; check it the way the CPSC describes. Plug a lamp into the GFCI and turn it on, press TEST, and the lamp should go off. Press RESET, and it should come back on. If TEST doesn't cut the power, the outlet is no longer protecting anyone, even though it still has power. The CPSC warns that GFCIs can keep supplying electricity after they've stopped providing shock protection, and recommends this test monthly.
Stop and call an electrician instead of resetting again if the outlet won't reset, trips the moment you reset it, feels warm, smells hot or shows scorch marks. The CPSC says unusually warm outlets can mean an unsafe wiring condition and should be checked as soon as possible. Our guide to warm outlets and switch plates covers what that can point to. And if the trouble is a breaker in the panel rather than the outlet's own button, see why a breaker trips when a kitchen appliance runs.
Who to call in Philadelphia, and what to ask
Call a licensed electrician, not a handyman. The U.S. Fire Administration says electrical work should only be done by a qualified electrician. In Philadelphia, the city's electrical permit page says a licensed electrical contractor must perform permitted electrical work, and the owner hires a licensed third-party inspection agency to inspect it. Simply replacing a receptacle counts as maintenance under the city's rules and may not need a permit, but repairing or rerouting damaged wiring, or adding outlets or circuits, usually does. Our guide on when Philadelphia electrical work needs an L&I permit walks through that line. In Bucks or Montgomery County, ask the electrician whether your township needs a permit for the repair.
Give the electrician your list of dead outlets, the weather pattern and your TEST/RESET result, then ask:
- Which outlets and fixtures does this GFCI protect, and where's the fault: an appliance, a downstream outlet or the GFCI itself?
- If water got in, what has to be fixed, such as a cracked or missing outdoor cover, before power goes back on?
- If the GFCI is replaced, how will you confirm it trips on test afterward?
- Does any of this work need a permit here?
If you're unsure whether a spot needs GFCI or AFCI protection in the first place, our guide on the difference between GFCI and AFCI explains both.