I stuck my 3-light tester in this receptacle at an inspection this morning while holding the exterior cover open with my hand. As soon as I pushed the test button on the tester, I got a jolt through the metal cover.
So, it would seem to me that there is an issue in the ground path, since the tester uses the ground to trip the receptacle.
Other observations; the receptacle did not trip when I pushed the test button on my tester, or when I got shocked. The receptacle did trip using the test button on the receptacle. The 3-light tester showed a good receptacle when I initially plugged it in.
Any additional thoughts by the electrical gurus? I just found it interesting, and glad I found a serious potential issue for my client, at the expense of a slight rise in pulse, lol. But would be curious if there are some other considerations here.
Of course I wasn’t about to pull the cover or anything to check that, but I wonder if instead of a bootleg, just a short from the neutral to ground could cause it? Such as if someone stripped too much off the neutral and then the bare ground crossed it when the wires were tucked? This was a newer home with grounded NM cable, so it would unlikely be an actual bootleg ground.
This was actually steel siding. But I like your picture, and I suppose it’s possible there is damage from a fastener.
My main thought is; how would the tester show a proper ground, yet current was fed through the metallic box cover and me when I pushed the test button on the tester? And also, why didn’t the receptacle trip when I was shocked, but did trip using the test button on the receptacle?
That’s fine and all, but actually, this condition wouldn’t have been found by only using the test button on the receptacle. This condition indicates two things to me. We have an issue in the ground path, and the receptacle did not detect a “leak” in the current.
We can play guessing games all day long about what “wouldn’t be found if I didn’t…”
Maybe it’s wired incorrectly, maybe it’s operationally defective, maybe there’s some other unknown circuit issue. All maybes, and yes, you might not have found one or two (without getting zapped a bit while holding a metal cover attached to metal siding).
I’ve read that GFCI’s do not guarantee to prevent all shocks, FWIW.
I can’t answer that question, my case was the outside light was flickering, I changed the light bulb and it was still flickering so I tested the wire from the switch to the light and found low voltage in the ground wire, I was baffled for a bit and decided to open the wall behind the light and by shit luck I found a nail in the wire, for some reason it did not trip the breaker, I cut two holes in the wall and replaced the wire to the switch. Not to say that is what is happening with your case.
I agree. I’m just saying that “use the test button on the receptacle only” doesn’t really address my question or explain the condition. It’s fine words to live by though, even if it would have a left a potentially dangerous condition undetected.
I think the reason I typically use the test button on my tester is because it can be hard to press the test button on the receptacle with the tester plugged in. So pushing the test button on the tester is just easier. Many times, I pull out the tester and then re-test with the button on the receptacle, which is also a good practice.
Except that, a bootleg ground has a path to ground, through the neutral conductor. Pushing the test button on a 3-light tester on a receptacle with a bootleg ground should not normally energize the gang box and cover. But, it typically won’t trip the GFCI either.
It would only become live in a ground fault in that circumstance, but you are going down the same path I am. However, that would also mean the ground path might be compromised, as the case should be grounded (in contact with the grounding conductor) anyway, since it is metal.
The ground path is definitely compromised. The box itself is clearly floating and isolated. The ground pin and wire are passing voltage to the case either through the socket or the wire inside is touching the case.
Also understand that you probably didn’t get the full ~120v jolt. Some probably did flow out the neutral and when the resistance matched you, you got some to.
Pushing test button on 3-light tester sent some (how much?) current to the grounding conductor.
Grounding conductor found me as the best path to ground, through the gang box and cover.
Then my last question, why didn’t the GFCI receptacle see this “leak” and trip? Bad receptacle? Or something else? Note; the GFCI did trip properly using the built in test button on the receptacle.
Since the ground pin is probably tied to the neutral, the test current flowed from hot to neutral instead of hot to a proper ground. The GFCI sees this as normal current flow (hot out, neutral back). It’ll trip when it sees an imbalance from hot to neutral. I.e. the current is running to ground so the neutral is in most cases seeing nothing or very little, but it will detect even minor changes.
