What type of Insulation??

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brother said:
What type of Insulation is Knob and tube wiring?? is it RHW? TW? Im just curious thanks. :)
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It can be almost anything; K&T describes the hardware and method, not the insulation type. See Art. 398 and esp. 398.104 ('02 NEC).
 
brother said:
Ok let me put it this way, what is the MOST COMMON they used in these old houses???
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Of the KT systems I've seen, most of the wiring was degraded to the point of not having any visible markings. I would hazard a guess however, that whatever it's rating is, it wouldn't exceed 60c, and would not carry any "W" rating, due to the decay of the natural materials used when exposed to moisture.
 
LarryFine said:
Yes. Now, what type would that be? Dunno.
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I wanted to be more helpful, but couldn't. Almost every house I work on has some vestigial knob and tube wiring in it, heck, my own house still has some. I've ripped out miles of the stuff, even some in remarkably good condition, and have yet to see a visible marking. :(
 
ceknight said:
I wanted to be more helpful, but couldn't. Almost every house I work on has some vestigial knob and tube wiring in it, heck, my own house still has some. I've ripped out miles of the stuff, even some in remarkably good condition, and have yet to see a visible marking. :(
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Sorry, Chris. My comment wasn't aimed at you!

I meant that I've never heard of that kind of wire having a type, other than as you described it: cloth-covered rubber.

You were exactly right.
 
Ive always put 15 amp breaker/fuses on knob and tube. I was in a discussion with a friend of mine and even though ive seen people/homeowners put them on 20 amp fuses, I tell them its just good practice to have it on 15 amp.

Seeing how old this wiring is and insulation is probably no mor 60celcius. I forgot to say this IS number 12 wire. :) even though it can be 20 amp, this insulation is just too old in my opinion.
 
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In my folks' house, I ran across some cloth-covered two conductor cable. What is the technical term for this stuff? It had a black and a white conductor in the cable.

This appeared to consist of 14 AWG copper conductors, and they were on a 15A breaker. The connections at the receptacle were good, but there were indications of heating on the neutral, for about an inch from the receptacle. What could cause this?
 
georgestolz said:
In my folks' house, I ran across some cloth-covered two conductor cable. What is the technical term for this stuff? It had a black and a white conductor in the cable.
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Sounds like some form of NM to me.
 
georgestolz said:
In my folks' house, I ran across some cloth-covered two conductor cable. What is the technical term for this stuff? It had a black and a white conductor in the cable.

This appeared to consist of 14 AWG copper conductors, and they were on a 15A breaker. The connections at the receptacle were good, but there were indications of heating on the neutral, for about an inch from the receptacle. What could cause this?
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You really don't get out much, do you? (Just kidding)

If the cloth is that sticky, tar-covered silver stuff, that's NM from the late 50's and the 60's, and they often used either grounding or non-grounding, sometimes even on the same circuit.

The heat damage is from a loose connection, either the wire-to-screw connection or the plug-blade contact inside the receptacle.
 
What type of insulation.

What type of insulation.

Hi George, Would you believe, the cabling is probably an early Romex with silver outer woven sheath with inner two conductor PVC without Nylon insulation jacket, and jute wrapped filler. If no jute then you have a collector's item but still can be recycled for the copper.:) Southwire holds the ROMEX trademark since buying the rights from General Wire. Got this straight from Dave Mercier of Southwire. rbj, Seattle
 
LarryFine said:
The heat damage is from a loose connection, either the wire-to-screw connection or the plug-blade contact inside the receptacle.
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I didn't really think about the plug blade contact, thanks Larry! :)

Well, now I know what that stuff is. Thanks all. :)
 
hillbilly said:
I believe that the outer woven cover on that NM is asbestos. If I'm not mistaken.
steve
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I don't ever recall NM cable having an asbestos covering. Anyone else ever heard of this?
 
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