PVC Cable and polystyrene insulation

[TerenceQ]

I have a load of 150mm HD polystyrene insulation board left over from a project.

I want to insulate my loft at ceiling joist level and floor it out for storage.

Somewhere in my head I think PVC Twin & Earth don't mix. Is this due to a reaction between the pvc and poly or does the cable generate enough heat to damage the polystyrene? Is there anything I could yous as a seperating layer where the insulation would be over a cable, cardboard?

Thanks for any advice

Terry

 

[ricicle]

You need to prevent the pvc cable coming into contact with the polystyrene. You also need to consider the possibility of cables overheating as well. (Lighting circuits are generally not a problem, but any power circuits will be)

 

[PrenticeBoyofDerry]

insulation over cables will reduce the current carrying capacity of the cables, generally lighting circuits on 5A or 6A are okay. but any power circuits such as sockets, shower, cooker etc will need to be laid above the insulation.
But the plasticizer in the PVC can react to polystyrene making it brittle, I believe the term to be marring!
So you must create a barrier between them, either clip above or lay above on some plastic sheeting.