Discolored kraft-back paper on insulation where it lays against romx

[ozark01]

I cut out a section of drywall today above a panel and when I pulled back the insulation the paper backing was dark (scorched?) where the romex was laying against the insulation. Some of the tar in the kraft-back paper was stuck to the outer jacket of the romex but otherwise the romex looked ok. It was #14 romex on a 15 amp breaker and this problem exists on all the wires leaving the top of the panel (about 6 cables)....each on their own breaker.

I looks like the wires may have been hot and I am wondering if anyone else has seen this occurrence and what was your opinion? The house is about 16 years old.

 

[renosteinke]

Maybe, maybe not.

Don't forget that the jacket of the Romex 'outgasses' a variety of chemicals known as 'plasticisers' over time. It would not surprise me that the tar and the vinyl have a chemical attraction to each other. Another possibility is that moisture accumulated just a bit longer behind the plastic.

 

[ozark01]

That's the kind of information I am looking for.....thanks! It doesn't look like the wires have been hot other than the discoloration so there has to be other explanations I would think.