On Tuesday, August 28, 2012 10:02:46 PM UTC+1, newshound wrote:



You may be thinking about the problem where *polystyrene* foam draws the

plasticiser out of PVC, making the cable insulation brittle so that it

fractures and "shorts" if it is deformed. This typically used to happen

in insulated ceiling voids and lofts where the cables are not usually

well fixed down, so that later modifications move cable some way away.

I'm not aware that polyurethane (expanding) foam does the same, but in

any case it is likely to be immobilising the wires here so that even if

the insulation all fell off it would not matter.



--

For every complex problem, there is a solution which is simple, neat,

and wrong.

H L Menken


Thank you.

Having started filling the hole today I decided to investigate relocating both 13A socket and timer spur and found that I was able to pull the ring cables supplying the 13A socket back under the floor. This means that I can relocate socket and spur timer with ease. Thus my concern about filler foam affecting PVC cable is irrelevant. However, yes, I was thinking about plasticiser migration so thank you for the info.

Rgds

Richard