I got shocked by a neutral wire on an outlet that was shut off at the panel once. That doesn’t make any sense. It’s a rare condition, but it can happen. It shouldn’t happen, but here’s why a neutral wire can shock you.
Can a neutral wire be hot?
Under ordinary conditions, the neutral wire shouldn’t be hot. The black wire should be. But not every house is normal. Sometimes you run into what my house inspector calls an Uncle Louie Special, where the lights and outlets all work, but the electricity doesn’t take a normal path from the box to the outlet or fixture and back. This creates an unsafe condition called backfeeding.
What causes electrical backfeed?
Electrical backfeed is a condition where the normal flow of electricity gets interrupted. In a normal household electrical circuit, a sheathed cable consisting of two or three wires runs from the panel up to your outlet or light. The power flows from the panel to the outlet through the black wire. Then the power returns through the white wire in the same cable back to the electrical panel.
When that normal flow along the same cable gets interrupted, the electrons are going to find their way home somehow. Tying all the white wires together is a common practice, and normally there’s no problem with doing that. But when there’s a stray black wire somewhere in the house that doesn’t have a corresponding white wire going back to the cable, the power takes a convoluted route back. It will find whatever white wires are tied together and take that route back to the panel. The power works, so it may not even be clear there’s a problem.
You find out there’s a problem when you go to make a change to an outlet. You’re minding your own business, doing everything by the book, shut off the power to the outlet, take off the wire nuts, brush up against the white wire and POW! For an instant, the easiest path to ground is through you, and you get a shock.
And that’s how you learn the hard way that a neutral wire can shock you.
This is the main reason why a bootleg ground is illegal and dangerous. This condition is even more fun when the ground wire and all the pipes in the house are also hot.
How to find a hot neutral wire
If you have a neutral wire shock you, you usually don’t want to have it happen again. I don’t remember every time I’ve been shocked by a black wire but I sure remember that time I got shocked by a white one. That one hurt worse.
The easiest, safest way to find a neutral hot wire is to use a non-contact voltage tester. After you cut off power to the outlet, run the tester over all of the wires to look for current. If the wires aren’t all dead, then you found a neutral wire that can shock you.
If you don’t have a non-contact voltage tester, you can use a regular multimeter. Remove the wire nuts, then measure for 110 volts between the bundle of white wires and ground, and between the bundle of white wires and the black wires. If you get 0 volts, you’re fine. If you get a 3-digit reading, you found a problem.
What to do about a neutral wire that can shock you
When you find a neutral wire that’s hot and shouldn’t be,it’s likely because there’s an unequal number of black and white wires running to and from the panel. Electricity will take the path of least resistance. And if we make it get creative, the patch of least resistance can become you or me, and that’s when we get a shock.
If you open up all the junction boxes and all the outlets, you can look for the telltale sign of a white wire not connected to anything. Hopefully it at least has a wire nut on it and it’s not a bare white wire sitting somewhere.
If you’re super lucky, you can tie that stray wire into the other white wires in the same box and fix the problem. But that probably won’t fix it. It’s more likely to break something else, which is why that wire was sitting bare in the first place. Uncle Louie didn’t plan it this way. More likely, he took everything apart just like you did, tried dozens of things, and this was the one thing he found that let all the lights and outlets work.
When I find this problem, I call an electrician. It usually requires running a new length of wire somewhere, and having a licensed professional figure out the corrective action is the best thing you can do. A good handyman can usually figure it out, but an electrician will probably figure it out faster. Now if I can find the stray wire, I go ahead and mark it to save the electrician some time.
How to work on a hot white wire before the electrician arrives
Of course, you may find this issue on a Saturday, and won’t be able to bring the electrician in until Monday at the earliest. If you find a problem like this in the middle of replacing an outlet or something else, and can’t leave the house torn apart all weekend, I get it. I’ve been in that situation too.
The easiest course of action is to wear rubber gloves while you’re working on the outlet. It doesn’t prevent every possible problem. But it reduces your chances of getting shocked considerably.
The other thing I’ve been known to do is shut off the main breaker at the box. This cuts off power to the whole house, but it ensures all of the wiring is electrically dead. This is an inconvenience because the whole house loses power, but it will usually only be for a few minutes, so it’s usually worth it.