Interesting. THE Boat Safety Scheme (Inland waterways) does not permit
PVC cable layed in polystyrene insulation foam as conatact makes the
PVC brittle and a fire hazard.

On Mon, 13 Oct 2003 00:19:24 +0100, "Andy Wade"
wrote:

"Martin Angove" wrote in message
...

Hmmm... come to think of it, what the OSG probably means is not to
lay cable and then pour concrete all over it. It is possible that
something in the unset/setting mix will react with the PVC. I really
don't know, and someone else here can probably advise better. When
putting cable in channel, the stuff is already set and so presumably
more-or-less inert?

I suspect it's more physical than chemical. Concrete (as opposed to sand &
cement screeds or plaster undercoats) contains stone chippings with sharp
edges. You wouldn't want to put a relatively fragile cable through mass
concrete which is going to be poured by the barrow load (or more) then
tamped or settled with a vibrating poker. The (un)delicacy of the
concreting operations just isn't compatible with the cable - even 10 mm^2
T&E starts to seem small and fragile in those circumstances...

In the floor screed I'd still use PVC conduit though - it's cheap and saves
an awful lot of hassle if you need to replace the cable.

Lawrence

usenet at lklyne dt co dt uk