RE: External conduits

["Hawes,Timothy Edward \(GEG\)" <haweste@xxxxxxxxxxxxxxx>]

> -----Original Message-----
> From: Jim Noble  Sent: 15 November 2004 09:55
>
> I need to run some cables under some timber decking. I figure
> some kind of flexible plastic pipe would do the trick. You
> can get ~32mm stuff readily, but that won't carry much.
> Anyone have a source of  ~50mm stuff?

There's this brown stuff at TLC, but it's not very big :-(
http://www.tlc-direct.co.uk/Products/MTMIN2BROWN.html

I've buried some 50mm ID black twin-wall trunking in the garden for
mains and LV cabling (2x ducts). I got a 50m roll and paid about 55 plus
vat from a place in Farnham, Surrey (mail me off-list if you'd like the
no.)  or any builder's merchant should be able to get it for you.

I've also used the 40mm push-fit waste pipe inside the house for cable
ducts between floors (hidden in a stud wall).

> What's the best way to top water collecting inside it?

Don't have any low points / pockets i.e. don't start at a high level,
drop down, then rise back up. I've recently discovered that a tumble
dryer exhaust vent makes quite a neat cover for the hole through the
wall and lets you maintain the correct bend radius for the cables
without the whole thing looking like a dogs breakfast (bring ducting up
into dryer outlet & secure, clip ducting to wall).

> I suppose I could use a bit of drain or waste pipe to form a
> complete dry route into the house at both ends...?

Also a good solution, and probably cheaper than 50m of twin-wall conduit
if you're only doing a short length and you'll also get a choice of
joints, bends etc. Plenty of silicone on the joints should keep it
watertight. You might also get it in brown too to disguise it a bit.

You might also want to think about how to make it rodent-proof i.e. stop
rodents using the ducting like a cat-flap. Squirrels are a problem here,
rats would be more unpleasant.

> Fix it to the underside of the decking joists, or let it lie
> on the ground? (it's shingle)

I'd clip it to the underside if it were me.

HTH,

Tim H.

+