Rag Wire question

[zcanyonboltz]

3 years ago I went through a friends rental property 1946 rag wire wired house and installed all new devices and fixtures. At about every outlet the wire was brittle and and the colored insulation was gone. I installed new pigtails to all devices and gutted the indoor panel and spliced new home runs to the outside panel. Everything has worked fine. I have another job like this coming up.
My question is, is the rag wire in the walls a hazard or is the hazard just at outlets were power is consumed. Also is there any reason to nolox the pigtails. Thanks.

 

[James L]

That all depends.

The wires in the box will heat up from sub-par connections, dirty, loose, etc. Or from having too many conductors in a 12 cu. in. steel box. Or both.

The whole wire length will heat up from continued load strain, bundling, etc.

I wouldn't use noalox, but if the conductors have really darkened, a few rubs with fine sandpaper or sanding sponge would help. Or electrical cleaner and a cloth.

 

[Dennis Alwon]

Usually the brittleness is at lighting outlets not at every outlet. The old wire was 60C rated so fixtures without insulation would heat up the insulation until it was brittle and feel off. I am surprised that this is an issue at outlet since the problem is only at the source of the heat.

I guess if the circuits were overloaded it could happen on the entire wire but not everywhere in the building.

 

[zcanyonboltz]

Usually the brittleness is at lighting outlets not at every outlet. The old wire was 60C rated so fixtures without insulation would heat up the insulation until it was brittle and feel off. I am surprised that this is an issue at outlet since the problem is only at the source of the heat.

I guess if the circuits were overloaded it could happen on the entire wire but not everywhere in the building.

Thinking back the lightning outlets were brittle ones, not all receptacle outlets were brittle but a few. The receptacle outlets wire insulation was gone at just about all outlets. The tenants were using 2 100W bulbs in most of the lights.

 

[user 100]

3 years ago I went through a friends rental property 1946 rag wire wired house and installed all new devices and fixtures. At about every outlet the wire was brittle and and the colored insulation was gone. I installed new pigtails to all devices and gutted the indoor panel and spliced new home runs to the outside panel. Everything has worked fine. I have another job like this coming up.
My question is, is the rag wire in the walls a hazard or is the hazard just at outlets were power is consumed. Also is there any reason to nolox the pigtails. Thanks.

Provided it hasn't been damaged and the circuit is/has been fused correctly, for the most part, the old nm is usually fine. The main concern w/ the old stuff is going to be the integrity of the insulation covering the conductors, and that insulation (cloth or rubber) tends to survive fairly well provided its been sealed up in a jacket, undisturbed and closed up in a wall-its when those cloth/rubber conductors get exposed to air (rec or switch box), or cooked (chronically overlamped ceiling fixture) is when there can be a problem- the wires may look like crap at one of those points, but you can skin a few inches of the old jacket back, and find fresh and still pliable rubber/cloth that is still more than capable of providing adequate insulation to the conductors inside of its original 60c rating-remember that even today in the age of 90c nm, we still follow the 60c column for nm.

And I see no need for the noalox- maybe clean the wire as mentioned above if dirty, but other than that, wire nut the connections and forget it- unless this is tinned copper that you believe is aluminum- and if thats the case, there is still no need.

 

[GoldDigger]

The tenants were using 2 100W bulbs in most of the lights.

Since most of those ceiling or wall mounted fixtures were only rated for 60W bulbs, I can certainly see a heating problem there!

I have some similar fixtures that have a foil coated fiberboard heat shield built into the wall side of the fixture. But that would not necessarily help with conducted heat down the wires themselves.

 

[James L]

Thinking back the lightning outlets were brittle ones, not all receptacle outlets were brittle but a few. The receptacle outlets wire insulation was gone at just about all outlets. The tenants were using 2 100W bulbs in most of the lights.

That is the most common scenario.

Light fixtures didn't have insulation in the base. And if it did, many times it was removed. Couple of 100 watt bulbs do a real good job of cooking the wires.