Cable running close to central heating pipe, de-rate it?

[Chris1234]

Evening, I’m normally an industrial electrician so never work in houses, but something I’m wondering about:

If you run a cable through space between ceiling and floorboards, do you de-rate the cable for ambient temperature if there are un-insulated pipes sharing the space? Obviously it’s going to get pretty warm in there!

 

[The Ghost]

Personally I would not. It is designed for an operating temperature of 70 degrees. I would attempt to make sure it is away from hot pipes by 50mm though. Insulation, yes I would derate it. Having seen cable running in conduit with hot water pipes and no appreciable thermal damage evident and various other such "atrocities" I tend to get a bit jaded about how exciting that isn't.

 

[Bellendian]

I reckon a lot of the de rating factors aren't really applicable to domestic stuff....
Regs have to account for circuits that will run at full design current 24/7 for months on end in industrial settings, this kind of thing just doesn't go on in a house!
Most domestic loads are running so far under the supposed design current, or are so intermittent that it's not likely to be a concern.

 

[robd]

I agree with the 70° rating wouldn't worry about derating it but wouldn't want it touching either so keep them apart.

 

[telectrix]

just stick a bit of asbestos between the cable/s and the pipe/s. don't forget your ppe. hard hat,gloves, eye and ear protectors steel boots ( bonded of course), dust mask, risk assessment , 2lb bar of CDM, horse fed and saddled.