Damaged NM sheathing

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  #1  
Old 03-09-05, 09:06 AM
Beeek
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Damaged NM sheathing

When I was adding some crkts to my SE breaker box I noticed my dedicated microwave wire (10 gauge NM orange) on a 20 amp breaker had damaged outside orange sheath. About 14 inches away from the NM clamp on the entrance to the box the sheathing was damaged (about one or two 1/4" circles). This is something I didn't touch that far up, I am positive it was existing. The internal conductor insulations look fine, just looks like a pulling hiccup by the contractor who built the place in December.

I have my township inspector due in soon to check out my minor work (crkt additions), if he notices, what will happen? I am nervous enough about the inspections (first time).

More importantly what should I do with the piece of wire? Is there an approved fix?

Thanks,
Beeek
 

Last edited by Beeek; 03-09-05 at 02:56 PM.
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  #2  
Old 03-09-05, 09:21 AM
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It's hard to say what the inspector would say. You can always argue that it was that way when you bought the house.

The only real fix is to replace the cable. You could replace the cable all the way from the panel to the receptacle, but that would be overkill.

You could simply replace the last two feet of cable. Find a convenient location and install a junction box, then replace the last two feet (or so) of cable. make sure that you use the same size cable, 10-2.

Here's another thought. I'm not sure what the ruling would be on this, and I'd like some other opinions. What about not cutting the cable, but rather disconnecting it and running it through a box. End up with the bad section of insulation inside the box. Reattach the cable to the panel. put a cover on the box. Any opinions?
 
  #3  
Old 03-09-05, 09:30 AM
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Location: Fayetteville, NY, USA
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If there is enough slack to pull it through a box, this seems fine. If I did this, I would very carefully trim off some of the outer sheath so you could see the undamaged (hopefully) individual conductor insulation.

I would never substitute electrical tape for damaged conductor insulation, but I might use it to cover a nick in an outer sheath, since that sheath is only for physical protection from damage to the conductor insulation. anybody else think this would be OK? (P.S., being somewhat anal, I would buy some 3M orange electrical tape to make the job look good.)

Juice
 
  #4  
Old 03-09-05, 12:33 PM
jim97219
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Keep in mind that if you go the box route Racraft suggests, the box will need to be accessible; don't bury it in the wall.
 
  #5  
Old 03-09-05, 02:36 PM
Beeek
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Orange shrinkwrap? Should I let the inspector tell me what to do? Point it out, it is on the back side of the cable.

How about flexible conduit for a short run? My furnace has that stuff on it just up to the rafters and it isn't attached to anything.

I would track down orange 3m tape if it would make the inspector happy. I thought black tape would be tackey.

It's a wierd 10 gauge also, kind of spiral conductor, I think it may be 10/3, b/c I now remember a thicker unconnected red wire with a wire nut capping it inside the breaker box. What a waste, they ran 10/3 up to my attic and then back down to my kitchen when they could have just run it in the basement and up. Did that with my electric range cable too.

I am guessing I would have to attach the junction box to something, which may be trickey for this install.

Thanks for your thoughts,
Beeek
 

Last edited by Beeek; 03-09-05 at 02:47 PM.
  #6  
Old 03-10-05, 05:39 AM
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Location: Fayetteville, NY, USA
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Beeek,

I didn't mention orange shrink tubing, it was 3M orange electrical tape. home Depot carries this product line in all colors. Don't think the inspector will care what color the tape is, and I don't even know if he/she will approve. It was just a time and money saving idea.

Installing a junction box and running new flexible (type MC, often referred to as BX) from the new box to the panel would be acceptable, but there's no reason not to run a new section of NM.

Juice
 
  #7  
Old 03-10-05, 12:59 PM
Beeek
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I thought the shrink wrap would be more like the original sheath than the tape. But I'll try it!

The plastic conduit is just a flexible tube with a water tight screw fitting on the end--I don't know the techinical term for it, I have it in one of my books at home. Kinda like SE wire protection (gray and shiney). They ran the 14 NM for my furnace out of a metal swtich box mounted to the side of the furnace up to the rafters of the basement and just stopped the conduit at I level.

I don't know where I can get just a couple feet of 10/3 cheaply, they mostly sell that in 100 feet or 250 feet. I figgured out last night why they used 10/3 maybe. Some models of the advantium microwave are 240 volt, some are 120. So they covered themselfs by running the extra red wire. My advantium is a 120 volt model.

Thanks,
Beeek
 
  #8  
Old 03-24-05, 09:36 AM
Beeek
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Juicehead, just as a follow up, I did tape up the damage w/ orange electrical tape from HomeyD's. I wound it really tight and layered it several times in different directions. At my inspection today I took my hand and ran it over the "patch" job for the inspector to see, and he didn't bat an eyelash.

3M tape is so much better than the crap my father used to bring home from "disgarded" rolls from the U.S. Army.

Speaking of orange, he noticed I used 10/2 for my home theather run, and commented, "10 gauge huh, that must have been fun."

With the small amount of damage, and the conductor insulation untouched, I am going to leave this with the tape.

Thanks,
Beeek
 
  #9  
Old 03-24-05, 11:14 AM
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beeek,

Glad to hear your inspection went well, especially the patch job on the nicked NM sheath. With no conductor insulation compromised and the 3M tape serving as physical protection, which is what NM sheath does, I would personally be satisfied leaving it that way in my own home.

Yep, I am also a fan of the 3M tape. For everyday electrical work I use the 3M Super 33+. It's flexibility, stretchability and adhesion is superior, and when you use it on electrical work it is pretty much there for good. Never seems to peel or dry out, even years after a job I've done where it is subjected to extremes in heat and cold.

Also, the adhesive seems to be impervious to water, and it seals against itself to keep water out of your work. In fact, I have used it, stretched tightly and overlapped, to patch and seal holes in the bottom of a P-trap in the drain piping under a sink, and never actually had to replace the trap.

I think the colored tape is 3M 35 series, which I use as conductor marking, and for odd jobs, such as your NM sheath repair or as handle tape on my 10 year old's home-made sword.

Anyway, glad it worked out for you.

Juice
 
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