What kind of wire?

Specific Inspection Topics Electrical Inspections
1

Hey Guys,

I am a new poster here, and have a quick question.

What do you call the wiring typically seen in homes built post 1940 that is similar to knob and tube wiring, but there are no knobs or tubes. The 2 conductors are encased in a loom? The wire loom/ insulation is stapled to framing as you would see with Romex.

2

In the 1950’s they had a 2 conductor Non-metalic cloth wiring. It’s similar to Romex, but with no ground. They called it “cloth covered NM”. Is that what you are referring too? A picture would be helpful.

3

Mark, thanks for the reply.

This is the stuff that is much fatter (for lack of better word) than the older Romex. The sheathing is a waxy black cloth type material. I should have taken a pic.

4

I can visualize what you are talking about in my mind, but I’m not sure what it is called. One of the sparkies will be along shortly with a good answer for you.

I’d probably just call it a Non-Metalic fabric covered cable. The bigger question is what it is made up of. Solid aluminum, stranded aluminum, copper, or tinned copper.

5

Thanks Mark,

It is pre - aluminum stuff by far. It is either tinned copper or copper.

6

“braided romex”.

It was actually worse than knob and tube, in my opinion.

7

Thanks Marc,

That is the stuff I was talking about. Once I had the name of the wire, I was able to find a previous discussion on this site with the pictures.

PS- I asked a couple electricians what this wire was called prior to posting, and the only thing they could come up with was SH!T wire (their wording).

Thanks again,
Ward

8

Well, that’s about my summation of the matter too.

It sure seems like the inside conductors were basically the same conductors that were always used for K&T, which we know has insulation that will break down with heat and time. Then, they take those insulated conductors, parallel two side-by-side (to double the heat), and wrap them in a thick insulating sheathing (to keep the heat in). Does this sound like a product that would last very long? It was a necessary step in the evolution of building wiring, but I still maintain that the old braided romex with the non-thermoplastic insulated conductors is the most hazardous of all vintage wiring methods.