Quick answer
A GFCI that keeps tripping is detecting a real ground fault — either moisture in a downstream outlet, an appliance leaking current to ground, or the GFCI itself has worn out. Diagnose by unplugging everything on the circuit and resetting; if it holds, plug items back one at a time to find the culprit. If it trips with nothing plugged in, moisture or wiring is the issue — call an electrician.
Key facts
| Common causes | Moisture in downstream outlet; Faulty appliance leaking current; GFCI worn out (end of life); Wiring issue downstream |
|---|---|
| DIY difficulty | Moderate |
| Time to fix | 20 min |
| Parts cost | $15–$25 parts |
| Tools needed | Non-contact voltage tester, screwdriver |
| When to call a pro | If new GFCI trips within days · wet-location issues |
What's happening
A GFCI monitors current flowing out on the hot wire vs coming back on the neutral. If more than ~5 milliamps flows to ground (i.e., through you or something wet), it cuts power in milliseconds. Bathrooms, kitchens, garages, outdoor, and basement outlets are code-required to be GFCI-protected because those are where moisture creates shock risk. Tripping isn't a defect — it's the point. The fix is finding what's causing the fault.
Common causes (ranked by frequency)
- Moisture in downstream outlet 40% of cases
Outdoor outlet, garage floor outlet, or basement outlet has water in the box. Common after rain, snow, or garage floor washing.
- Faulty appliance leaking current 30%
An old refrigerator, freezer, well pump, dehumidifier, or power tool with degraded insulation leaks current to ground. Unplug and retest.
- GFCI worn out (end of life) 15%
GFCIs have a 10–15 year lifespan. Older ones nuisance-trip more often. If nothing else explains it, replace the GFCI ($15–$25).
- Wiring issue downstream 10%
Cross-wired neutrals (neutral touching ground somewhere in the circuit) causes chronic tripping. Requires electrician to trace.
- Improperly wired GFCI (line/load reversed) 5%
During installation, if line and load terminals are swapped, the GFCI trips repeatedly. Verify with multimeter or call electrician.
How to diagnose
- Note when it trips. After rain? When a specific appliance runs? Right when you reset it? Each points to different causes.
- Unplug everything on the circuit — walk the house and unplug every load on outlets that go dead when this GFCI trips.
- Reset the GFCI. If it holds with nothing plugged in, plug items back one at a time — the culprit is whatever trips it.
- If it won't reset even empty, the GFCI itself may be faulty or there's a wiring issue. Kill power at breaker and inspect for moisture in downstream outlets.
The fixes
Fix #1 — Find and remove the load causing the fault Most common
Systematic unplugging identifies the offending appliance in 15 minutes.
Tools
Materials
- Reset the GFCI with all downstream loads unplugged.
- If it holds, plug items back one at a time, waiting 30 seconds after each.
- Whatever trips it is the culprit. Common: old refrigerators, well pumps, aquarium equipment, outdoor Christmas lights, power tools with damaged cords.
- Repair or replace the offending appliance. If it's an appliance you can't be without (freezer), an electrician can help you determine if the appliance can be salvaged or needs replacement.
Fix #2 — Replace the GFCI
If it trips with nothing plugged in and moisture is ruled out, the GFCI has failed. Replacement is $15–$25 and 15 minutes with power off.
Tools
- Non-contact voltage tester
- Screwdriver (Phillips + flat)
Materials
- Replacement GFCI outlet ($15–$25)
- Kill power at the breaker. Verify with non-contact voltage tester at the outlet.
- Photograph the existing wiring — note which wires are on LINE terminals (power in) vs LOAD terminals (power out to downstream outlets).
- Detach wires from old GFCI.
- Attach to new GFCI matching LINE/LOAD positions. Do not swap — this causes tripping and reduces downstream protection.
- Screw GFCI into box, install cover.
- Restore power and press reset.
Prevention
Cover outdoor outlets with weatherproof 'while-in-use' covers (bubble covers) — flip-lid covers only work when nothing is plugged in. Replace 15+ year old GFCIs proactively. Never use extension cords to power appliances long-term outdoors — they degrade fast and cause chronic GFCI trips.
When to call a pro
When to stop and call a pro
- New GFCI trips within a few days — indicates a persistent circuit fault, not a bad GFCI.
- You can smell burning or see moisture in any downstream outlet — kill power and call.
- The circuit has a bathroom, kitchen, or exterior outlet you can't identify — troubleshooting circuits requires expertise.
- You have aluminum wiring — GFCI installation on aluminum requires special care (AL/CU-rated devices, antioxidant compound).
Electrician diagnostic to find phantom GFCI trips: $150–$350. GFCI replacement labor: $100–$180. Circuit rewire if needed: $300–$800.
Cost estimate
Cost estimate
Frequently asked questions
Moisture is entering the outlet box or the connected extension cord. Solutions: weatherproof 'in-use' bubble cover ($10), replace old extension cords with outdoor-rated (SJTW cable), reroute cords so connections stay dry.
The tripping isn't dangerous — it's the protective function working. What's potentially dangerous is the underlying ground fault. Never bypass a tripping GFCI or replace it with a regular outlet as a 'fix' — that removes protection while leaving the fault in place.
Yes. Press the TEST button monthly — power should cut immediately. Press RESET — power restored. If TEST doesn't cut power, the GFCI has failed internally and needs replacement.
Code requires GFCIs on all bathroom, kitchen, garage, outdoor, basement, laundry, crawl space, and pool/spa area outlets. Bedrooms and living rooms typically don't need GFCIs, but do require AFCIs. Check your local code — updates over time have expanded requirements.