Answer what you can see below. This ranks the likely causes, gives you one safe next check, and tells you clearly when to stop and call a licensed electrician.
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.
What can you see?
Diagnosis
Example result — change the answers on the left and the ranking updates for your situation.
Most likely cause
Open ground — the receptacle has no equipment-grounding path, so surge and fault current has nowhere to divert
Ranked by fit to your answers
1
Open ground — the receptacle has no equipment-grounding path, so surge and fault current has nowhere to divert
80
SAFE NEXT CHECKStop using it for anything that needs a ground (surge strips, computers, metal-cased tools). The grounding conductor is missing or broken; locating and restoring it means opening boxes with the power off.
Where to stop. Reading a plug-in tester is homeowner-safe; correcting any miswire means working at the receptacle terminals with live conductors — if you cannot do that safely with the power off at the breaker, stop and call a licensed electrician. A 3-lamp tester cannot detect a bootleg ground, a reversed multi-wire circuit, or undersized wiring. This is general information, not a quote and not a substitute for a licensed electrician.
Rule trace — why this ranking
Tester legend indicates "open ground", which decodes directly to this condition. +80
What to do next
Try the safe next check above. If it doesn't resolve the problem — or if sorting it out would mean opening a panel, touching wiring, or anything past a simple visual check — stop and call a licensed electrician. Don't replace parts on a guess.
Confirm it with
Plug-in outlet/GFCI testerMultimeter
Not your exact situation? Change any answer above and the ranking updates — or try a related situation below.
source-governed · verified 2026-06-20
Sources
code NEC 406 — Receptacle wiring and configuration requirements · verified 2026-06-20
standard UL 943 — GFCI TEST-button protection behavior · verified 2026-06-20
Named standards and manufacturer guidance, re-verified on a freshness schedule. When a source cannot be re-verified, the dependent rule is suppressed rather than asserted.
My tester shows open ground. Is the outlet safe to use?
It will power most things, but anything that relies on a ground — surge protectors, computers, metal-bodied tools — is unprotected. An open ground means a fault can't be cleared the normal way, so it should be corrected rather than ignored.
The tester says correct. Does that mean the wiring is definitely safe?
Not fully. A 3-lamp tester confirms hot/neutral/ground positions but can't detect a bootleg (false) ground, a reversed multi-wire circuit, or undersized wire. 'Correct' is a good sign, not a guarantee.
Which result is the most dangerous?
Hot/ground reversed. It can put voltage on the grounding conductor and on a device's metal case, so exposed metal may be live. Shut the circuit off at the panel and correct it before using the outlet.
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.