"Bob Eager" wrote in message
...
On Wed, 2 Feb 2005 00:56:11 UTC, Andy Wade
wrote:

"Bob Eager" wrote in message
...
Ducts presumably count as trunking, so the cables will have to be
derated as per the regs. So you'll need better than 2.5mm2 for a final
ring circuit, for example, unless protected at (say) 20A.

oh bum !

That's wrong though. The cable for a 32A ring only has to achieve 20A
in-situ rating, which a single 2.5 T&E cable in conduit, trunking or
duct easily does. You'd only have to go up to 4mm^2 if dictated by the
application of grouping factors with cables of other relevant circuits,
or unusually high ambient temperature.

I was assuming that there would be grouping if he was making ducts -
perhaps there isn't...!


thinking about it, the cable density is very low. The only problem I can see
is that the wide vertical duct will carry central heating pipes too - but
I'll insulate and keep them seperate. In essence my proposal isn't much
different from running cables behind drylining.

Is it possible to obtain meter tails longer than 1 metre ?

I would like to move my CU ...

thanks...

Jeremy