I finally saw how a 'clean' cable run could be a total fire hazard

I was checking out a new apartment complex last week in Portland and noticed the installer ran all the coax and ethernet tight against a heat duct in the basement. One side says it's fine because it's not touching any electrical, but the other side says the heat alone can degrade the jacket over time and cause shorts. I've seen it go both ways in the field where some guys swear by zip ties near vents and others refuse to do it. What do you all think, is it a real risk or just overly cautious? Has anyone here actually had a jacket fail from heat exposure?

3 comments

3 Comments

emmaclark4h ago

Man that's a good point about the heat rating on the cable itself, most people grab whatever cheap spool is on sale and don't even think about the temperature spec printed on it. I've pulled old coax out of crawlspaces near vents where the jacket was so brittle it cracked just from me bending it a little, and that's the kind of slow failure that can turn into a short or signal loss without anyone knowing. It's not gonna cause a fire tomorrow but over a few years it's just stupid to gamble on cable sheathing that's not rated for the heat you're packing near it.

kimr742h ago

Had a buddy who ran HDMI cable through his attic and six months later the picture would flicker anytime the AC kicked on. Pulled it out and the jacket was literally flaking off in his hands near the flex duct.

quinna896h ago

I've seen this same debate play out in attic spaces where people run speaker wire near furnace exhaust pipes. A buddy of mine had a cable in his own house that got brittle and cracked after four years of being within a foot of a heat register. The outer jacket just turned into dry, crumbly plastic. It's not an immediate danger like touching a live wire, but it's one of those things where you're betting the heat rating on the cable matches what the duct puts out over a decade. Most people don't check the temperature spec on their coax, they just assume it's fine.