The tester indicates reversed polarity. That is a wiring fault with shock implications; stop using the receptacle and have the wiring evaluated by a licensed electrician rather than opening the device or moving conductors yourself.
source-governedDiagnostic estimate. Not a quote, not a substitute for a licensed electrician.source pack dated 2026-09-13 · authority hashes pending
Where to stop. Reading a plug-in tester and using its TEST function as directed by the manufacturer are homeowner-safe observations. Do not open a receptacle box, move conductors, or attempt wiring correction; those are licensed-electrician tasks. The cited RT250 does not indicate ground quality, multiple hot wires, neutral/ground reversal, or most combinations of defects. This is general information, not a quote and not a substitute for a licensed electrician.
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.