A reversed-polarity tester reading on a GFCI that won't reset points to line/load reversal or a miswire.
Stop and call a licensed electrician or emergency services now if there's smoke, sparks, a burning smell, heat, shock, or water near the problem. Otherwise it's safe to answer the questions below.
The likely readout
Most likely cause
Line and load reversed, or a miswire (a GFCI cannot reset with power on the LOAD terminals)
Ranked by fit to your answers
1
Line and load reversed, or a miswire (a GFCI cannot reset with power on the LOAD terminals)
80
2
A downstream wiring fault (damaged/pinched cable or a neutral-to-ground contact)
40
3
The GFCI device itself has failed (will not reset with power confirmed and no load)
35
SAFE NEXT CHECKWith the power OFF at the breaker, verify the incoming feed lands on the LINE terminals (not LOAD). A tester confirms orientation after.
Where to stop. Resetting and plug-in testing are homeowner-safe. Opening the box, checking terminals, or rewiring line/load means live conductors — if you cannot do that safely with the power off at the breaker, stop and call a licensed electrician. Water plus electricity is a shock hazard; do not keep resetting a wet outlet. This is general information, not a quote and not a substitute for a licensed electrician.
Try the safe next check above. If it doesn't resolve it, or would mean working on wiring or a panel, stop and call a licensed electrician — don't replace parts on a guess. Open the full tool to change any answer for your exact situation, or try a related check below.
source-governed · verified 2026-06-20
Sources
code NEC 210.8 — GFCI protection requirements · verified 2026-06-20
standard UL 943 — Standard for Ground-Fault Circuit Interrupters · verified 2026-06-20
Electrical Fault Check provides general diagnostic information only. It is not professional advice, not a quote, and not a substitute for a licensed electrician. Do not work on live wiring. If you see smoke, sparks, burning smell, heat, shock, water exposure, or repeated tripping, stop using the circuit and contact a licensed electrician or emergency services as appropriate.