old NM wire-has small ground wire

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Old 10-19-08, 11:01 PM
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old NM wire-has small ground wire

As I am remodeling/putting on addition, I am trying to update electrical. I have found lot of dead wires, old bx with very fragile rubber insulation, old NM with cloth wrap that is very damaged (mice in past?) and some old NM that I thought was OK, but it has very small ground. the 12-2 wire has what looks like maybe 18 gauge ground that is wrapped around the outer jacket and then tightened against the metal box with clamp. I don't like how it is just wrapped and would pigtail a ground to the box, but with the ground being so small, I was concerned that maybe need to replace the wire. There are several circuits using this type of wire. That is my last post tonight! thanks guys
 
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Old 10-19-08, 11:39 PM
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That sounds interesting!

Does the ground wire wrap around the wire for its full length? (Was the wire manufactured this way?)

Or is the ground wire from inside the jacket and someone installing it wrapped it around the last few inches or whatever?

In any case I would replace the wire.

If the wire was manufactured that way, it would be interesting to see a picture of it.
 
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Old 10-20-08, 12:02 AM
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The uninsulated ground is inside the jacket. It looks just like modern NM, except the ground is small. Someone took about 4 inches of it and would it around jacket where it enters metal box and then clamped around it so that box is grounded. In one location, there is bx connected to box, so the ground is the armor (there isn't any ground inside the armor) and if there is more NM leaving the box it has ground done same way. at boxes, they are relying on the connection between yoke and box to carry ground. Probably best to just replace it.
 
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Old 10-20-08, 07:04 AM
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Since it sound like you have exposed the wires I would just go ahead and replace it. That wire is 40 some years old.
 
 

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