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.)