Receptacle tester malfunction????

Hey All,

anyone ever had all three lamps light up when testing an outlet? Any idea what it means?
Tested several receptacles and only one in particular in this house caused all three lamps to light up. This happened last week, after several inspections since then no other readings like that.
As always, thanks and keep safe.

Mark Ellison

Every time I have had this occur, the receptacle was improperly wired with 240 volts. You should attempt to verify this with another instrument.

Never had all 3 light up. But I have had the small ‘Lowes’ testers fail when testing GFCI function. I always keep a spare and sometimes use a SureTest for confirmation.

Ditto down south of Jeff.

Yes, this schematic shows that all 3 lights would come on with 240 volts.

Three-prong tester schematic.jpg

Many thanks Gents!

Ever had one show very DIM center light when using…had an electrician do this on a MUNI-Inspection and plugged the tester in and one of the lights were dimmer than the other…ended up being a poor on the neutral at the device connection…