Getting 15.6V On Dead Circuit - Why ????

nasTTcar

I am showing 15.6 volts on my outlet hot wires, even though power is not on that circuit.
Here's the background.
I have just put in a new room in my basement. The room has 6 outlets around the perimeter and 10 "can" lights in the ceiling on 2 switches.
All electrical is run in conduit and the hot wire comes from a 20A circuit and all wiring is 12ga. solid copper. All is installed in metal boxes.
All commons are twisted tightly together and wire nutted.
I used a blue wire for one light circuit, a yellow wire for the 2nd light circuit, and black for the wall outlets.
When I have the lights on in the room, I get 15.6 V showing on the black wire for all of my wall outlets.
Because all of this is now behind sheetrock, and several of the runs are through flexible whips, it is impossible to pull out or pull back any of the wires.
What is going on, and what are possible solutions?

mickeyco

15.6 volts on the hot wire to what? I've never been able to get a voltage reading off just one wire, sounds spooky, maybe gremlins*(not the car). Sharing neutrals? Is the "black" wire in a conduit with other "hot" wires? Is every thing grounded? Was this installed by a licensed electrician (if so call him/her back)? What are the commons you speak of? Could be phantom voltages, that sounds spooky too, maybe time to call Ghost Busters.

The solutions:

Answer this guys (jadnashua) questions and maybe he can help:
http://www.terrylove.com/forums/show...ewpost&t=14146

Call an exterminator or Ghost Busters if it's something paranormal.

Call an electrician, they're real good at fixing electrical stuff.

Seriously, it's probably nothing** (what type of meter are you using), but with the lack of information I doubt anyone here could give you a definitive answer, if you don't know what you are doing and are concerned, call an electrician in to figure it out, that's what they do, and most of them are real good at it.


* A gremlin is a folkloric creature, commonly depicted as mischievous and mechanically oriented.

** May actually be something, could end up burning your house down, who knows.

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Speedy Petey

Wow. This sounds like it was extremely over-engineered.

Blue, yellow and black?
All "commons" tied together? Can you elaborate a bit on this one?

Still sounds like phantom voltage to me.

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mdshunk

Yup.

Read all about it:

http://www.nema.org/stds/eng-bulleti...ulletin-88.pdf

MSSI

must be that blue wire..maybe try using orange or purple ?

Sorry......But seriously. Try using an analog meter. I bet you get zero voltage.

HallisseyDesign

Agreed- I had one today that the breaker in the box a 20amp was off and that breaker fed the line I was working on.The line had 19.7 volts going to it. It was strange, I have been shocked plenty of times so I went back and turned off the switch and still had the same voltage. So I did the next best thing touched the wires so I knew my meter was working right. Well it was! If any of you guys think I am crazy well anything above 30 volts I am not touching on purpose! Ok back to your issue. It is probably just residual resistance. Nothing to worry about. The only time I would worry about it is if your power to the switch is off and the light still turns on because of that extra power running the line.

househelper

But since it had voltage, shouldn't it be residual voltage? Like leftover meatloaf?

boman47k

Is somewhere in these responses the explanation of how some copper thieves have been killed stealing ground cables?

HallisseyDesign

Yea sorry my bad. Wrong word! residual voltage is what i ment! i had one today I was working on. Everything in the box was off except for 2 breakers. Both sump pumps. I got shocked good! It had 57.8 volts in that line my fingers were tingling for about 20 mins after that! I am still trying to figure it out and that was around noon and it is 2:08am now!

boman47k

Twice within a week?? Whew! I always thought just throw the breaker. Makes me want to disconnect all wires on a circuit now at the panel.

mahlere

i hate when my old lady serves residual voltage....never as good the 2nd time around....

but seriously, i found that making sure all the wires are bent down allows all the residual voltage to fall out. makes it a little safer..

mdshunk

Yes. I think it's in the 2008 code that all cable wiring systems and raceways shall be arranged to drain. When this can't be done, a stop and waste valve shall be installed at the low points in the cable or raceway system. This permits ready draining of the residual voltage after the breaker is opened, and allows for safe repair of the wiring. It's kind of a complicated code section, but they snuck it in right under the no more than 12 devices on a circuit requirement.

mahlere

ya know, i vaguely remember a CMP proposal on that...i'm glad they passed it....

Celtic

Why are you holding out on me?
I was told I couldn't get the '08 until after I returned my '05 with all relevant sections highlighted.

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Magnettica

Current leakage?

I though that was what neutrals were for!

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A.W.Davis

troublemaker

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HallisseyDesign

I figured it out. I did just that and rang out every wire in the box and in the house. Found the problem. Damn backwired lines. Not enough neutrals he was missing like 6 or 7. The line I touched was backfed off of the pump that was still on. Somehow it was not a full charge persay but I fixed it by pulling new wire for it. The really funny thing is where I got shocked was 2 floors above the pump!

boman47k

I was wondering how it managed to leak uphill , but it seems this was not a leak afterall. Seriously, I bought an old trailer once and noticed someone had come off one side of dryer circuit to run a 110 somewhere (washer rec, I think). When I got this thing where I wanted it, I disconnected everything at the panal and ran all circuits down before having any power ran to it.

robertc65

Why did this thread die so soon. It was just getting fun. I think the OP was sucessfully scared off or maybe he got shocked by the 15.6 volts. He never mentioned what kind of engineer he was. I'm a computer systems engineer and we know all about residential power

Sparky Joe

I would definetly use purple wire in this situation, and instead of an analog meter I would just put my tongue to the wires, That's always been the best 'no lie' voltage tester to me.