Romex: Burn or manufacturing defect?

[kallisti5]

Lets play a round of burn or manufacturing defect. Trying to decide if calling in an electrician is in order. That romex supplies the AC blower / natural gas heater.

Builder ran, unmodified.

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[kallisti5]

I should mention it is more purple in color vs brown (which is why originally I thought it was simply an error in manufacturing)

[Jim Katen]

Can't say I've ever seen anything like it. When you saw it up close, did it look burned?

If I hadn't seen the title of this thread, I would have thought that someone drew a sharpie across it.

[Jim Katen]

Your average air handler draws 11 amps or less. Hard to imagine it pulling enough power to heat up the cable.

[Marc]

I've seen something very similar many times when I pulled the romex too tightly up against something metallic (partially driven staple, nail, plumbers plates, etc) and created the marks you see. When I see it, I look for sheathing torn open and insulation damaged. That's about it.

Marc

[Rob Amaral]

something got on it in the process of fishing???

[Marc]

something got on it in the process of fishing???

It caught on something during the pulling.

I start my new construction wiring jobs by bridging an inside corner nearest the SE with a pipe that has a 1000' ft spool of 12/2 wg on it. I pull all the home runs first. Some runs might go clear across the house and will snag sometimes. If it snags on metal, it'll make those marks if I pull too hard.

Marc

[kallisti5]

something got on it in the process of fishing???

It caught on something during the pulling.

I start my new construction wiring jobs by bridging an inside corner nearest the SE with a pipe that has a 1000' ft spool of 12/2 wg on it. I pull all the home runs first. Some runs might go clear across the house and will snag sometimes. If it snags on metal, it'll make those marks if I pull too hard.

Ah. That makes sense and explains the odd shape of the marks... I took a close up gander and while there is some disturbance of the surface, it doesn't seem very deep.

Thanks for the input! Given the close proximity to the natural gas line I just wanted to be *sure*

[Speedy Petey]

This is extremely common, which is unfortunate since folks immediately think burning when they see it.

Most times I see this associated with older craft faced insulation. There is a tar-like substance somewhere in the craft that will impart these marks on white NM cable.