Insulation and Cables

[Pat Tester]

We all know you should not run PVC cables in Foam insulation (Kingspan etc) as the foam
attacks the pvc. However is this the case for Upvc ? Can you use conduit or trunking
or even 1.5" domestic waste pipe to run cables through this. I have a job and need to
run pvc and some swa through the 100mm underfloor insulation, it will be laying onto the concrete slab. Will the foam attack the Upvc ? Any ideas ? regards

 

[Skotz]

PVC that is used to make conduit and trunking is different from cable sheath PVC. In cables a plasticiser is used to keep the cables flexible and its this plasticiser that migrates on contact with polystyrene causing the cable sheath to become sticky and eventually brittle. The PVC used to construct conduit and trunking is unmodified and is a hard brittle material. So my thinking is that by protecting the cable with either conduit or trunking should be ok. Hope this helps.