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Is this a fire hazard?

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streetcore

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I peeled back some insulation in my mom's attic today looking for places to air seal and found what looks like burn marks on some tar-paper faced insulation (see attached pics). The marks follow the path of a wire running to a track light in the kitchen. It used to run four 60W bulbs, but I recently switched them to 40W equivalent LED bulbs. The light is controlled by an older dimmer switch.

This doesn't look good to me. Could it indicate a fire hazard?
 

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wyliesdiesels

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IMPO that looks more like stains than burn marks.

Notice the water marks on the dry wall?

Im thinking that there was a water leak and the blackness was transferred from the wire to the insulation.

EDIT: Other idea is spray paint now that i look at the third photo.
 
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OP
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streetcore

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Thanks for the quick reply. I wondered if it might be moisture related. The attic is not well insulated and there are air leaks everywhere, which is why I started peeling back the insulation in the first place. When I saw those black marks it kind of scared me.
 
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LS6 Tommy

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I was thinking it's some sort of a stain from the insulation, too. I may very well be wrong, but I don't know if that type of wire is supposed to be used that with with that box, at least not without some kind of bushing. Please correct me if I'm wrong...
 
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KRB52

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Experiment time. Turn on the lights for that box, then go back into the attic. Give it a little bit, then touch the wire (insulated part). If there is a problem, you should feel it being too hot. Also, give the black areas in the insulation the "sniff test." If it smells burnt, eh, she may have a problem. If you try this, make sure you wear a dust mask so you don't inhale fiberglass.
 
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rlitman

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KRB52 said:
Experiment time. Turn on the lights for that box, then go back into the attic. Give it a little bit, then touch the wire (insulated part). If there is a problem, you should feel it being too hot. Also, give the black areas in the insulation the "sniff test." If it smells burnt, eh, she may have a problem. If you try this, make sure you wear a dust mask so you don't inhale fiberglass.
Click to expand...

I'd avoid touching the wire. If the insulation is going, it may flake off and shock you.

If you had a thermal camera, the solution is easy.

Barring that, I'd turn the power off, and give the wire some flexing. See if the insulation has gotten "crunchy" from being overheated.

To me, that looks like kraft paper faced insulation, and I'm not familiar with tar-paper faced insulation. But let's for a moment say that the fiberglass side of that paper were coated with tar. A warm wire could melt that tar and have it soak through the paper like that.
 
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wyliesdiesels

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To me, the third photo looks like the wire is glossy as in black spray paint.

If the wire was getting hot, the insulation wouldnt be shiny glossy like that.

LS6 Tommy said:
I was thinking it's some sort of a stain from the insulation, too. I may very well be wrong, but I don't know if that type of wire is supposed to be used that with with that box, at least not without some kind of bushing. Please correct me if I'm wrong...
Click to expand...

Good catch.

There should be clamps on that wire.
 
OP
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streetcore

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I double checked the wire insulation and it looks good. No cracking or flaking. The light was on when I first discovered this and the wire didn't feel hot to the touch then. There was some tar on the wire, which may have made it look glossy in the picture. I was able to wipe that off.

I moved the wire, put the insulation back down and will check it again later.

Unfortunately I don't have a thermal camera. I wish I did and I think it would really come in handy with this insulation project.

I wondered about the wire clamps as well. I'm hoping to get electrician friend to come over for a look on the weekend. There's a couple things in that attic that look a bit sketchy.
 
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DenisG

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Don't know if you can read any identification numbers on that cable, but if it's rubber insulation it's probably past it's lifetime. Rubber insulation was discontinued in the 60s.
 
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Dagny

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Your nose is the best detective here. Go to the end of a piece of insulation and separate it from the paper is there black stuff in between them? Also look at other wires see if they are doing that.
 
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MikeF2316

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That looks exactly like my attic. Electrical boxes too. My house was made in 1950, I would imagine this one is from the same era. My original wiring all has asphalt/cloth insulation, like the other wires in your picture. All my original wiring doesn't have a ground wire. :sad:
 
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NUTTSGT

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Cmreschke said:
That box is being used correctly. The clamp is internal, notice the screw protruding between the top knockouts.
That box is designed for that.
Click to expand...

I was going to mention that also. You can also see the galvanized plate of the clamp in the slots of the knock out.


OP, if you have the skill and for peace of mind, since you are pulling back the insulation, you could run new wire.


EDIT: Now that I look back at those pictures, does the wire in question have a crease/groove down the center ? It almost looks like the wiring I pulled out of our landscaping for some outdoor (low voltage ??) lighting.
 
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Whitworth

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Kraft paper backing is acidic. That explains the discoloration, a chemical reaction with the wire jacket. Moisture may also have been present and accelerated the effect.
 
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