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Electrical wiring problem - 1937 house, appear to be missing wire, diagram link

Electrical wiring problem - 1937 house, appear to be missing wire, diagram link

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  #1  
Old 11-23-10, 07:17 AM
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Electrical wiring problem - 1937 house, appear to be missing wire, diagram link

Hello,

I am rather new to this site, but have found helpful information here in the past. I have a wiring problem in a 1937 house. Essentially I have a light fixture (and junction?) box with five wires coming through it. One wire is always on and hot.

One wire is a hot broken by a switch. One wire is a neutral, that when connected with the always on and hot powers an electric outlet and another switch down the line. The other two are unidentified, and do not create a circuit with a hot wire (which means by themselves not neutral or ground). I suspect these two wires feed another light fixture. I labeled these wires A B C D and E.

I have a diagram (rather crude) that I created of the entire circuit...it is in PDF format. Thanks very much for looking, any feedback would be appreciated.

http://freepdfhosting.com/e4817c9c8e.pdf

Chris
Arlington, VA
 
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  #2  
Old 11-23-10, 08:10 AM
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Wires

Give us some details about all the wires entering and leaving the switch on the right side of your diagram.
 
  #3  
Old 11-23-10, 08:50 AM
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More details....

Thanks for your response (and for looking!) The only information I have about the wires going into the switch and out of the switch is that one is an always hot and one is a hot broken by the switch (I added as much to the diagram).

I also changed the way A & B appear, as they are currently spliced in the box to give the outlet and basement power.

Here is the link:
http://freepdfhosting.com/8d9e2e1d91.pdf

Thanks again!
 
  #4  
Old 11-23-10, 10:17 AM
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I think you may be calling some of the neutrals "always hot" and that could be confusing.
 
  #5  
Old 11-23-10, 11:10 AM
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not sure...

How to respond...by "always on" i mean it is not interrupted by the switch.

In terms of confusing hots and neutrals, if I get a 120v reading from toughing the hot wire to the ground of an extension cord (there's no ground in this receptacle), I assume that the wire is a hot wire.
 
  #6  
Old 11-23-10, 11:36 AM
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Wires

Give us some details about all the wires entering and leaving the switch on the right side of your diagram.
How many wires and what color?

Does the power cable from the breaker panel go to the light fixture or does it go to the switch?
 
  #7  
Old 11-23-10, 11:44 AM
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more details...

All the wires are black fabric covered, rubber insulated copper. There is no distinguishing color or marking (ribbing, etc.) on any of them.

From my continuity testing, the line from the circuit breaker goes to both the switch and the outlet (one hot line to each). I cannot tell, at the moment, where it is split (there are several junction boxes in the basement, I imagine it is there).

Sorry, I said it in a previous post/diagram but it's worth repeating. The switch has two wires (appears to be a hot going in and a hot going out - and the switch simply "breaks" the line).
 
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Old 11-23-10, 01:00 PM
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How to respond...by "always on" i mean it is not interrupted by the switch.
All wires interrupted by a switch should be hot. If there are two wires then the other is neutral. That is modern wiring.

It sounds like you have K&T (knob and tube) wiring. Sometimes they put the switch on the neutral. That is now not allowed. Also at lights and receptacles they sometimes "borrowed" a neutral from another circuit. Never allowed now. Not saying either applies in your case but these and "California three ways" are irregularities you must keep in mind.
In terms of confusing hots and neutrals, if I get a 120v reading from toughing the hot wire to the ground of an extension cord (there's no ground in this receptacle), I assume that the wire is a hot wire.
That is a good method. You should also measure between the wide blade of the extension cord and a wire you believe to be neutral. If that is 0v and a measurement to the narrow blade is 120v then it is most likely neutral and should be marked white*.

I would mark all wires black or white using this method before trying to unscramble what is there. But that's just me. Hopefully Wire puller38 can help you with the given information.

*If a wire measures 0 or 240v to the narrow blade of the extension cord it should be marked black. Also mark the wire on the load side of the switch black.
 

Last edited by Gunguy45; 11-24-10 at 05:32 AM. Reason: Member request
  #9  
Old 11-23-10, 07:42 PM
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*If a wire measures 120v or 240v to the narrow blade of the extension cord it should be marked black. Also mark the wire on the load side of the switch black.

Ray, Wouldn't it be 0v or 240v if you are going to the narrow blade of a extension cord?
 
  #10  
Old 11-23-10, 08:41 PM
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Originally Posted by fubar2578 View Post
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Ray, Wouldn't it be 0v or 240v if you are going to the narrow blade of a extension cord?
Yes. I screwed up. Thanks for catching that.
 
  #11  
Old 11-24-10, 04:44 AM
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Thanks - finally got it working..

It was indeed a "borrowed neutral." According to my electrical engineer buddy it's not a fire hazard, but it's not done anymore. basically have one neutral (which he says can carry 240) supplying two hot lines.

Thanks for the feedback! Everything is now marked and labeled after the continuity testing, so if I have to rewire, I know what feeds what!
 
  #12  
Old 11-24-10, 05:45 AM
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Wiring

Good! Thanks for letting us know!
 
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