I’m remodelling my basement and replacing my electrical boxes and moving them out 1/2 inch for drywall.
The box that contains the main switch for the basement and the staircase gave us big shocks. I investigated and found a loose ground wire. When I reconnected the ground, the shocks stopped.
I still think that there is something wrong. I don’t think there should be shocks even without a ground.
I have checked all the outlets connected to that circuit and I don’t see any loose wires.
What could be wrong?
It sounds like something hot has continuity to the box but the resistance is still too high to allow the leakage to trip the breaker. I’d shut everything down, take the wires off the switch and ohm everything out to find where you could have continuity. My guess is that either there’s continuity inside the switch between a terminal and the switch body, or else a bare wire is lightly touching something inside the box.
So you have a voltage on the metal switch box? Is this circuit connected to any 3 or 4 way switches? If so, I’d look for the following a nick in any the insulation on the hot wires or the wires used to connect the 3 or 4 way switches. If no nicks in insulation I’d tape the terminals where the hot wires connect to prevent inadvertent contacts.
There is a three way switch in the box and also just a standard switch.
Everything works as it should, just so you know.
It’s possible that when the switch was pushed back it the box thataground wire was touching a hot wire. Taping around the switch would fix that.
So there is no way that it is a problem with another outlet or switch in the same line?
Is it possible that the three way is wired wrong? I mean it works after all.
I had the exact problem of the bare ground intermittently touching and shorting to the untaped terminal at our house. They should be taped but sub-contractors and their labor force take a lot of shortcuts.
If all your switches work in the logical fashion they should and your ground wire is bare and your switch untaped I’d think taping would be the solution.
A hot touching the ground or box should blow the breaker. You have some type of indirect short. Is there a receptacle down stream that could be using the ground for a neutral, not enough wires pulled and someone cheated? Is something wet? How old is the wiring and other components? Something could be breaking down. Was a switch box or one of the lights opened and maybe pinched a wire when it was closed? Any vibration or heat on the circuit that damaged a wire nut or other splice point? Is the electrical box mounted to a metal stud? What ground wires enter the box from away from the breaker panel, such as the lights? How are the lights grounded? The ground path should be unbroken; in other words, all the wires should be spliced together and not using the box as a termination point. Whatever the problem is should not be between the switch box and breaker panel. Something is using the ground for a return path.
One possible test to isolate the problem:
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re-loosen that ground wire like it was before, so the box gives shocks again (but use a tester, not your body!).
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Disconnect everything downstream (might be easier to do at the next box, so you don’t disturb anything in the box in question.
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Then test: does the box still give shocks? If yes, the problem is in that specific box, not downstream. If no, then the problem is downstream (or you fixed it when moving wires around – that’s all too common with ‘intermittent’ problems like this).
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Reconnect the downstream circuit, then test again. If you now get shocks, then the problem is in the downstream circuit. If no, then it’s an annoying intermittent. Reconnect the ground wire, tape over the switch terminals, check (maybe even tape) hot wire nuts, test again to make sure it doesn’t give shocks now, and leave well enough alone.
I’m pretty sure that all of the connections are correct. During my reno, I have pulled all the outlets and switches. Certainly, the ground is not used improperly.
- Everything works as it should and there are no shocks. Should I be worried about anything?
- Are you saying that ground wires should NOT be connected to the metal box? This seems to be common practice in all the boxes I have opened. All the grounds are connected sometimes using the metal box as the connector. Why are there ground screws in the box then?
Code requires a ground on metal boxes.
It sounds like you have a neutral touching ground. Maybe a nick in the insulation.
A intermittent short can get hot and possibly cause electrical fires.
A nicked wire for example, could be partially shorting to the metal box. The gap creates resistance and that causes heat.
I’ve see charred wires several times. Thankfully no fire. Usually a loose wire nut connection caused it.
A toaster is just a coiled resistor wire that heats up. Same idea.
Technically, this isn’t proper according to the latest code. You should have a short pigtail screwed to the metal box, then the other end of that wire-nutted together with all the ground wires.
But in practice, lots were done this way, and sometimes still are – and the box functions effectively as part of the ground wire circuit.
Of course he does – the neutral & ground are bonded together back at the breaker panel. I’m not sure how this would cause the shocks.
Anyway, he’s now eliminated the shocks. I’d suggest leaving it alone.