I used a standard three-lamp outlet tester on an GFCI outlet, and it shows "open ground". Should I be worried?
This is not a special "GFCI tester"; it's just an ordinary plug-in three-lamp receptacle tester. I have tried multiple GFCI outlets throughout my house, and some of them show "correct", but two show "open ground". I'm not sure whether to be concerned about that.
My impression is that GFCI outlets are sometimes used in places where there is no true ground available. So, this makes me guess that the outlet tester might indeed show "open ground" on such an outlet, and that it won't be a
problem. Is this correct?
(If it's relevant, these are pre-2016 GFCI outlets.)
Best Answer
You are correct, GFCI receptacles can be used to replace old 2-prong receptacles when there's no grounding conductor. If your home is old enough, you might assume that there is no ground at the receptacle. However, if you want to know for sure, you'll have to inspect the wiring inside the box.
A properly functioning GFCI receptacle, can provide ground-fault protection without a grounding conductor. So as long as you're not plugging in high-end audio/video equipment (or anything that requires surge protection), you're probably okay.
As @Harper mentions. Press the Test button on the GFCI, and make sure it trips and resets properly. Repeat this test every month, as these are likely not GFCIs that self test.