Stray current in common wire

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Old 07-13-13, 08:31 AM
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Stray current in common wire

I was adding a new outlet and I had the circuit breaker off for that branch. Upon removing the wire nut for the common (white) wire I felt a slight tingle from stray current. This branch is passing through EMT and shared with two other 120v circuits plus a 220v for a heat pump. Thinking I might other problems, I turned off the other breakers for the corresponding branches in the EMT but when I touched the two common wires together a second time I still noticed a small arc. I had a freezer temporarily plugged into this same branch. Upon unplugging the freezer the stray current disappeared. Any possibilities as to what's occurring?
 
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Old 07-13-13, 09:00 AM
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This branch is passing through EMT and shared with two other 120v circuits plus a 220v for a heat pump.
Do the 2 other 120 volt circuits just share the same conduit or does one of those other circuits share the white neutral conductor as well? I assume you also turned off the 240 volt circuit to the heat pump, correct?

I turned off the other breakers for the corresponding branches in the EMT but when I touched the two common wires together a second time I still noticed a small arc. I had a freezer temporarily plugged into this same branch. Upon unplugging the freezer the stray current disappeared.
So, you are saying that when all breakers to circuits in this conduit were off, you had an arc of the white neutral conductor? Just curious, what prompted you to unplug the freezer if that circuit was turned off?
 
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Old 07-13-13, 09:56 AM
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A White circuit conductor , presuming the wiring is in accordance with the NEC , is the "Identified" circuit conductor , the color "White" indicating this is the "Grounded" circuit conductor.

If the Grounded circuit conductor is one of the three conductors that comprise a "Multi-wire" Branch-Circuit , it is the "Neutral" conductor in regard to the two "Live" conductors of the three-wire Branch-Circuit.

A break or open in the Neutral conductor of a three-wire Branch-Circuit can cause a voltage "un-balance" across the circuit loads; it's possible to have 180 volts across one load , and only 40 volts across another; 180 + 40 = 240 , the voltage across the two "Live" conductors.

You will have to determine if the White conductor of the circuit- connection you opened is the Grounded Circuit conductor of either a two-wire Branch-Circuit or a three-wire Branch-Circuit.
 
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Old 07-13-13, 02:10 PM
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The other two 120v circuits share the same conduit. I shut off the power to those two plus the circuit to the heat pump. I unplugged the freezer because I wasn't sure if the problem could have been within it's circuitry such as a capacitor or loose wire since the unit was moved recently. I called an electrician who I know and he said it could very well be a capacitor. This is at my second home and I'm not there now. Later next week I plan to go out with a meter, try to duplicate the problem and do some readings.
 
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Old 07-13-13, 05:41 PM
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By all means, please let us know what you find once you do some testing. Looks to me like you are in the Ballwin/Manchester area and I thought it strange you would have a heat pump there. Can I ask the approximate location of this second home, I am assuming it's somewhere in the country.
 
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Old 07-13-13, 06:43 PM
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The country place is located out near Hermann, MO. I'll let you know what I find out.
 
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Old 07-14-13, 06:23 AM
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Hermann is a beautiful little town, I've been there for Maifest, but that was many years ago, and used to know the people who had an ice cream shop there (30+ years ago). Do your testing before you go to the wineries!
 
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Old 07-27-13, 06:24 AM
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Joe, I opened the junction box, disconnected the wire nuts (after turning off the circuit) and checked the wires again for stray current but never found anything. I'm sure whatever was the initial cause had to do with the freezer. The freezer is over 20 yrs. old. With the new technology and the need for a smaller freezer, I'm considering replacing the unit. The freezer was a freebie (maybe a freebie for a reason).
 
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Old 07-28-13, 12:55 PM
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I'm sure whatever was the initial cause had to do with the freezer. The freezer is over 20 yrs. old. With the new technology and the need for a smaller freezer, I'm considering replacing the unit.
I'm not a fan of junking appliances just because they're older. That said, it sounds like this one has a problem, regardless of its age, and that it's in a home that no one may be in for longish periods of time.

I would hate to pull into my second home late one evening, relying on food I had left in the freezer, and find that it had failed and that I would have to buy new food as well as a new freezer.
 
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Old 07-28-13, 04:53 PM
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It does sound like there is something going on with the freezer. It is 20 years old so even repairing it may not be cost effective and a new one would probably be a lot more efficient to operate too. I also think I'd just get a new one.
 
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