60VAC in ceiling wires with the light switch turned off

[knuttle]

Was replacing a two-bulb typical ceiling light fixture as the bulbs keep burning out seemingly prematurely (although I don't count the hours).

With the light switch off, I remove the old and start to put in the new and as I do so my hand burns for a split second as it brushes against the black (hot) wire.

Whoa! I get down from the wooden ladder and grab my voltmeter.

Lo and behold, 57.8VAC between the black (hot) and white (neutral). I pull all the tangled wires out but I don't see a visible bare metal touching but I haven't checked the light switch as it just happened.

Do you think the constant 60VAC was why bulbs were burning out? (Most were the curly kind as I was trying to use them all up.)

The replacement is an LED Flush Mount Costco item 1600246.

If the 60VAC isn't coming from the one light switch in that side room, then I'm not going to be able to figure out where the ceiling fixture hot is getting the 60VAC from.

Do you think the constant 60VAC will damage the new LED light?

[Ralph Mowery]

Unless the switch going to the light has some leakage/feed through the voltage is probalby induced from other wires close by. If using one of the digital volt meters they often show voltage when there is actually very little current for the voltage. That is if you put a load on the wires such as a light bulb the 60 volts will drop to a very low value.

You say you were on a wooden ladder. Were you touching something else when your hand touched the black wire ? Such as holding on to the new light sockets.

[invalid unparseable]

The first thing I would check is the on/off light switch to see if it is not completely cutting off the current in the off position. Maybe it is still making a high resistance connection in the off position.

BTW, this is why you should always turn off the circuit breaker when working on wires !

[trader_4]

Right, disconnect the wire at the switch, see if the voltage is still there. Anything else that logically would be on that switch?

[trader_4]

I would agree, except that he says he felt a burning sensation on his hand. That suggests it's more than some induced voltage which would be very low current.

I doubt it has anything to do with the bulbs burning out, unless it's more current than we think. I would think it would have to be enough to heat the filament up considerably to get it to age. But the LED likely isn't going to like it. It will probably light up when off.

[trader_4]

I would agree, except that he says he felt a burning sensation on his hand. That suggests it's more than some induced voltage which would be very low current.

I doubt it has anything to do with the bulbs burning out, unless it's more current than we think. I would think it would have to be enough to heat the filament up considerably to get it to age. But the LED likely isn't going to like it. It will probably light up when off.

[Scott Lurndal]

Is it a 3-way switch? Is the traveller wired correctly if so?

[Dean Hoffman]

I'd be curious about the readings from hot to ground and neutral to ground also.

[Marilyn Manson]

Sounds like you might have an Edison Circuit, also know as a "shared neutral". That means that a second breaker needs to be turned off.

A Edison Circuit works as follows:

From the breaker, you run a 3 wire cable (2 hots and a neutral) to a junction box. At that junction box you create two branch circuits using two 2 wire cables (1 hot,

1 neutral, each) by attaching each branch circuit hot to a hot in the 3 wire cable and the 2 branch circuit neutrals to the single neutral in the 3 wire cable.

Each hot of the 3 wire cable would be tied to 2 different breakers. If any of the devices on the "other" circuit are on, voltage can be fed back through the neutral of the other circuit as you have found.

You either have to find that 3 wire cable and determine which other breaker is being used or just start killing breakers one by one until the "phantom voltage" goes away.

Remember... I said "sounds like". That is what I would look for first, but it could be something else that is actually a problem. Edison Circuits aren't a "problem", they are just tricky.

Stay safe!

[Marilyn Manson]

Turning off a single breaker might not solve the issue if it's a Edison (aka shared neutral) circuit. Sometimes you need to turn off 2 breakers.

That is why you always test the wires, even after turning the breaker off.

I recently ran into situation where the panel box was labeled such that Breaker 6 killed both fixtures controlled by a switch box with 2 switches in it. I shut off Breaker 6 then poked my non-contact tester into the switch box. One switch still had power.

Turned out there were actually 2 circuits in the switch box. Perfectly code compliant, which is why I always check for power before touching anything. I never trust somebody else's panel labeling and sometimes don't even trust my own.

[trader_4]

An Edison circuit doesn't explain getting a shock from the hot wire with the switch off. Also code going back a long time has required those circuits to have a simultaneous disconnect breaker, ie tied breaker. But IDK if very old ones required it.

[Marilyn Manson]

We don't know how the switch was wired. I'm not discounting any possibility at this point. I'm also concerned that the OP is replacing fixtures with just the light switch off.

Required vs. followed are often two very different things, especially when DIY'ers start messing with a panel.

[Dean Hoffman]

Peabody recently posted about having some breakers that didn't have the code required breaker ties.

[knuttle]

That's a given that there is something leaking into the hot wire.

If it's not in the ceiling fixture, and if it's not in the light switch, then my only other option is to crawl around in the attic (which is no fun) to see if the wires are visible.

The Fluke showed an almost non varying voltage of around 60VAC (I'm rounding off) where I've seen many cases of a few volts, maybe five or six, which jump all over the place. this was more stable than what I've seen in the past.

As noted there is no indication of current as I didn't put a resistance in between the leads as I'm looking for a high wattage resistor as we speak.

But just now, while I was typing that up, I decided to see if it would blow a fuse, and I touched the black to the white, and nothing happened.

No blown fuse. No spark. I checked afterward and it was back to 57.4VAC.

So the current is below the threshold of the circuit breaker which is probably 10 amps (maybe 15?) for a light circuit.

Nah. The wires are hanging down as I removed the old fixture and unscrewed the wire nuts to do so. The two wires and the ground are all there is now.

The ladder was wooden thank God just in case I got shocked.

And I know what a shock feels like as there is no mistaking it. We used to stick a butter knife in the sockets when we were kids so I'm well aware of that tingly sensation.

It was definitely the hot wire and there's no way not to be somewhat grounded in some manner by your feet unless you're suited up in rubber which I wasn't.

[knuttle]

Same. The ceiling box is the original which is grounded. The fluke read the same hot to ground, and hot to neutral.

And zero neutral to ground. Well, not zero. I just checked while writing this. 0.208VAC.

The advice to shut off the circuit breaker is right but I was being lazy. I "knew" the switch would be off and I even taped it in case the other half used it without me knowing about it. And I don't know which is the right circuit breaker (some day I'll label that damn panel).

I didn't "expect" any voltage on that line and even disconnected the wire nuts without any occurrence but when I brushed the back of my hand against the black wire, the hot sensation was unmistakable.

The Fluke confirmed it.

What I'll do, I think, is I'll first finish putting the new light on as the second unit will kill me if I don't do that. Then when she's not looking, I'll remove and check at the paddle switch. It doesn't switch anything else to my knowledge so it should be simple to check the incoming and outgoing voltage.

If that doesn't isolate the problem then I'll crawl up in the attic but I hate getting all that fiberglass all over me and it's in a narrow portion a few feet from an outside wall so it will be a tight fit for a fat man.

Or, I'll just leave it as I didn't realize until a few minutes ago that shorting the black to the white didn't even spark so there's not much current (just enough to feel, I guess).

I wonder though how 60 volts gets induced in a wire.

[Marilyn Manson]

In fact, required vs. followed are often two very different things, even when professionals are involved.

This is a true situation:

A buddy had his service upgraded by a licensed electrician. Now that he had a bigger service and more room in the panel, he asked me if I could help him run some circuits. So I go over and pull the cover off the panel. I looked at the neutral bar and find that instead of adding a second bar like he should have, the electrician doubled tapped most of the neutrals. 2 wires under almost every lug. Not this, but like this.

I told him to call the electrician and have him fix it before we do any work. The electrician started bitching about having to order parts, then extend the wires, etc. "It really doesn't matter. The way it's wired is fine."

My buddy: "Then you won't mind if I call the town and have them inspect your work."

Electrician: "I'll be over next Tuesday."

[knuttle]

House was built in the 1980s and is to that code. Nobody messed with the breakers, I'm pretty sure of that. I'm the second owner though but I have no reason to suspect the first.

And I'm not sure what all this edison stuff is about but I've never had to switch off a ganged breaker for just a light switch circuit (although I don't know what else is on this same circuit).

There are ganged breakers but they are for the AC and other 220VAC items.

I'm not worried about hitting the mains if/when I need to but the question now isn't about safety but about debugging. Once I hit the breakers, all I have is resistance whereas with the breakers on, I have telltale voltage.

[trader_4]

First thing I would do is disconnect the light wire at the switch, then measure at the switch terminal and at the light fixture end of the wire.

[Marilyn Manson]

First thing I would do is turn off the breaker. You may now proceed. ;-)

[Ralph Mowery]

I worked at a plant that had a licensed electrician and I would not let him change a battery in a single cell flashlight of mine.

Big differance in what works and what is legal and safe.