Electrical Fault CheckHome electrical diagnostics

METHODOLOGY

How the Outlet tester result decoder works

The ranking is rules, not opinion — here is exactly how an answer set becomes a ranked result and a safe next check.

source-governed Diagnostic estimate. Not a quote, not a substitute for a licensed electrician. sources verified 2026-06-20 view sources ↓

Method

  1. The tester's printed legend is the authority: each named condition decodes to one wiring state, shown with the rule and weight that produced it.
  2. GFCI behavior is evaluated separately from the wiring lamps — a GFCI whose TEST button does not trip it is not protecting, no matter what the lamps show.
  3. A 3-lamp tester has documented blind spots (bootleg ground, reversed multi-wire, undersized wire), so a 'correct' read is reported as necessary-but-not-sufficient rather than a clean bill of health.

Sources

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.

Use the tool

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.