50vac on EACH leg of 12/2 HELP


  #1  
Old 11-26-04, 08:38 PM
ibizian
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Question 50vac on EACH leg of 12/2 HELP

I had a light that worked but when I turned on another on the same circuit BOTH dimmed to less than Ĺ. I went up into my attic and re-ran new wires to the living room light. That one works fine now.
The light that powered the living room is a wiring mess. I have 2 14/3 with nothing on them I have a 12/2 with 50vac on BOTH legs (yep 50 on the black and 50 on the white!) for a potential of 110vac between them. I am not sure where either of the 50vac is coming from but nothing else in the house is acting funnyÖ I have NO 110vac at the switch. I now know why the lights dimmed but I canít figure out why the voltage drop of 60vac. Any help would be great as I will have great difficulty getting to this in the attic.
Thanks
 
  #2  
Old 11-26-04, 09:10 PM
R
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Is this something that just happened or are you working on the circuits and this was a result. When you say you reran new wires what did you do as to the existing wiring. Give us an inventory of the cables entering the switch box and light fixture/fixtures before you worked on them. If you are using a digital voltmeter dont use it they are near worthless on house wiring use a simple neon tester or analog multimeter.
 
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Old 11-26-04, 09:57 PM
5
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Sounds like you have one or more opens. The multimeter essentially becomes part of the load, hence 1/2 the voltage appears across it. If you remove the light bulb or anything plugged into the circuit, do the readings change?
 
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Old 11-27-04, 05:20 AM
R
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Put away your digital multimeter and don't use it on an ac circuit again. It does not work properly all the time, and you cannot rely on the readings unless you know what you are doing.

Yes, you hava a mess. You need to sort this out.
 
  #5  
Old 11-27-04, 07:26 AM
ibizian
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I will try to be more clear. The living room light is now on itís own circuit and not related any more.
The other light is the problem. In it there are 3 sets of wires. One is abandoned and used to go to the living room light. It reads nothing. The only reason I did not pull it is it is stapled to the studs ever 6 inches or so. The other goes to the light switch. It also reads nothing. The third comes in and is the questionable one.

I am not a licensed electrician but I do have over 10 years as an industrial and marine electrician. So I sort of know how to read my meter. Yet I have never seen anything like this. Either way I go to ground or to neutral I get 50vac on BOTH lines. I will have to go up in the attic again and see where the 50v comes from.

Thanks for your help and keep the ideas coming.
 
  #6  
Old 11-27-04, 04:12 PM
J
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Sounds like a possible open neutral to me or something wired in series.
 
  #7  
Old 11-27-04, 06:00 PM
ibizian
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Did some more digging. A fan/light combo was also on that circuit as is one more light. The fan was wired from the main panel and was wired correctly for a double switch. I did find that if I went from leg to leg I got my 121vac. HOWEVER when I went form the hot to the metal box that is NOT grounded (house too old) I found my 50vac. The wiring there is the armored cable obviously there is a voltage potential to an ungrounded box but how? Old wiring touching the box? I suppose since it is the armored cable the box would technically be grounded to the panel I checked the panel and no leakage there so it must be up in the attic.

Thanks
 
  #8  
Old 11-27-04, 06:08 PM
J
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I reiterate earlier advice you got to put away your digital multimeter. Once it is safely stowed out of reach, go read this article on phantom voltage.
 
 

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