gfcigrounding
I just finished a home wiring project which has a set of outlets protected by a GFCI outlet. I was testing them with an outlet tester and noticed something odd:
Immediately after a GFCI test, my outlet tester reported that the GFCI protected outlets had an open ground. If I did a second test, the error went away.
I was able to repeat this consistently – every other test I'd see an "open ground" indicator.
Is my GFCI outlet defective?
Update: I'm using a simple outlet tester, like this one.
The National Electric Code, these days, says garage receptacles are supposed to be protected by GFCI [NEC 210.8 (A)(2)]. That could be a GFCI outlet that is in the garage, or it could be a GFCI breaker in the panel. Anyway, if code was followed, that is. The branch circuit supplying the outlet in the garage is not supposed to supply outlets outside of the garage [NEC 210.52(G)(1)], but who knows, your garage could be tied to a GFCI outlet in another part of the house. Not very likely, but possibly. First, I would try checking to see if there is a GFCI receptacle in the garage. If there is, then make sure that it is reset. If it is a new GFCI outlet, then it may have something called Smart Lock, which means that you have to go back to the panel and turn the branch circuit off for about a minute, then turn it back on, then go out and reset the GFCI. My best guess, is that your problem has to do with a GFCI device that has tripped. It may be an outdoor receptacle that is causing this, even though there is not supposed to be outlets on that same branch circuit that are outside the garage.
GFCI plug in testers with a trip button won't work without some ground connection. When the test button is depressed it is basically a high resistance leak to the ground pin, with no ground wire connected the test fails.
Specifically this type of device:
Additionally: If the outlet is GFCI protected but has no ground it should be marked "GFCI protected No Equipment Ground" with the stickers that came with the device.
Best Answer
sounds more like something is wired wrong. The test button should drop the hot, not the ground. with the hot out, your tester would be dead all 3 lights. The black wire should go to the brass colored screw. The white wire should go to the silver screw. The bare copper should go to the green screw. these are on the feeder side, the wires to any other outlets follow the same color code but they should be fed from the bottom looking at the back of the GFCI outlet.