DIY fire hazard question

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  #1  
Old 03-13-06, 10:40 PM
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DIY fire hazard question

Wiring safety / fire question:
I have a newly constructed drywalled basement room, where a 3 way switch was planned. 4 conductor romex wire is running above the ceiling, to each of the junction boxes where the switches go. It appears that a drywall screw hit the 4-conductor wire.

I got an extra piece of wire and a multi-meter, disconnected all switches, and found on the 4-conductor wire:
From the white wire in junction box 1, I get a reading of zero ohms to any of the (white or black or ground) wires in junction box 2. I get a reading of 1 (infinity) from the white wire (in junction box 1) to the red wire (in junction box 2)

I'd much rather have a single 2-way switch than to wreck the finished drywall. (but I'd rather wreck the drywall than have a fire hazard).

So the question: Can a set of shorted (black, white, ground) wires be the neutral wire, then the red wire be the hot wire? If a screw is shorting the wires, is there any fire/electrical hazard?

Here's more detail:
junction box 1 needs a working light switch and is inaccessible (drywall on cement & foamboard wall). The feed wire goes to junction box 2. The only wires between the junction boxes is the 4 conductor wire - which is shorted to act like 2 conductor wire. There are pipes and sheet-metal ducts in the ceiling. The can lights are now using the ground wire (which would act like a normal white wire). All the drywall screws are covered in mud (can't touch any of them). If I don't use the shorted 4-conductor wire, I have to damage the drywall and snake another wire...


Please help - I'd hate to create a fire hazard. Thanks.
 
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  #2  
Old 03-13-06, 11:39 PM
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You have to replace the damaged section of cable. You are opening yourself up to all sorts of problems if you don't, including the fact that there still may be more damage than you are detecting.

And are you saying the you are using a ground wire as a neutral? And THEN not having a ground?
 

Last edited by MAC702; 03-14-06 at 08:55 AM.
  #3  
Old 03-13-06, 11:55 PM
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Thanks for the reply.

The 4-conductor wire acts like 2 conductor wire (due to damage like a screw, I'm assuming). With an ohm-meter, the white on one end has conductivity (zero ohms) with the white and black and neutral on the other end of the wire.

The ground-black-white will effectively all be the neutral (unless I rip out the wire). I'd connect the hot black feed to the red of the damaged 4-conductor wire.
 
  #4  
Old 03-14-06, 04:22 AM
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You already know what the correct answer is: don't use this cable without repair. The insulation is damaged and the _conductors_ may be damaged.

You have no way of knowing if the wires that are shorted together are also cut most of the way through, which means that they could form a 'hot spot' when current flows through them, and you have no way of knowing if the wires are about to touch the red wire creating a further short circuit.

You should either replace this cable, or use junction boxes to jump the damaged section.

-Jon
 
  #5  
Old 03-14-06, 04:24 AM
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Replace the cable. There is no room for debate. You are creating numerous safety risks and code violations by continuing to use the damaged cable.
 
  #6  
Old 03-14-06, 04:31 AM
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Originally Posted by steveInSolon
Can a set of shorted (black, white, ground) wires be the neutral wire, then the red wire be the hot wire? If a screw is shorting the wires, is there any fire/electrical hazard?
You've been given the answer, so I won't repeat it.

Instead I will ask the question, What do you think the inspector will say during the inspection?
 

Last edited by John Nelson; 03-14-06 at 07:27 AM. Reason: Don't ridicule the posters
  #7  
Old 03-14-06, 09:45 AM
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Originally Posted by steveInSolon
It appears that a drywall screw hit the 4-conductor wire.
It appears that either the screws you used were longer than 1.5" or the cable was improperly installed.

How do you know how many screws there are in the cable?


I'd rather wreck the drywall than have a fire hazard
You have a fire hazard.

You have a serious fire hazard.

You have no choice that does not involve wrecking the drywall.


> Can a set of shorted (black, white, ground) wires be the neutral wire,
> then the red wire be the hot wire?

Never.

> If a screw is shorting the wires, is there any fire/electrical hazard?

Yes! Both!


> I have to damage the drywall and snake another wire...

Correct.


> I'd hate to create a fire hazard.

It has already been created.
 
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Old 03-14-06, 07:03 PM
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Agreed with all above !

Now, what type of ceiling ? drywall, drop, spline etc.. If you have access above the ceiling at the sw. locations you have hope, even with the foam in the walls (that I hope is flame retardant).
Step back and explore your options. But disconnect the damaged cable first!
 
  #9  
Old 03-14-06, 07:40 PM
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Thanks for the replies. I'm not going to use the damaged wire. Will bypass (causing some drywall work, which is fine).
 
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