Cable Conduit

[me]

I'm rewiring some security lights and PIRs and am thinking of putting in cable conduit to make it tidy. I've been browsing the Screwfix catalogue and I am considering using their 20mm conduit, three way tee-boxes ( containing terminal blocks) for exit of cable from conduit, inspection elbows etc.

How would I seal the end of the conduit where cable exits to make it weather proof - can you get grommets which will seal the end and allow cable exit - I can't see any.

When you join the conduit using couplers or tee-boxes what do you seal joints with?

What do you use the Screwfix Adaptors(D13910-79) for - to what do they screw?

[John Rumm]

Tis what I did with mine....

Ah, the trick is (if possible) not have the wire ever exit the conduit. So the conduit runs right upto and fixes to the equipment (i.e. light / PIR etc)

You would ideally need some form of gland. If you wanted a home made solution then a combination of keeping the exit point inverted (so the cable comes out downwards) and sealing with silicone ought to do it.

Glue it together with solvent cement like you would plastic waste pipe fittings. That way the whole lot is welded together.

These fit into the 20mm knockout that is provided in many electrical accessories. A small 20mm hole saw is very handy for opening suitable connection holes in the fittings (even if they were not designed woth a knockout!)

If you click on the "enlarge picture" link for this:

can just about see the knockout position at the top of the picture. You take out the blanking plug, and fit the terminating fitting into the hole and tighten it up. This leaves a nice 20mm female stub to stick your conduit end into.

[me]

On Sun, 18 Jun 2006 03:39:24 +0100, John Rumm wrote an excellent response to [e-mail]'s query on Cable Conduit:

You sir, are a gentleman - many thanks.

[Lobster]

Forgive me if I'm teaching grandma to suck eggs, but you do know this stuff is intended for use with single-core cables,

You'd have great difficulty using it with conventional PVC insulated twin-core and earth?

David

[ARWadsworth]

Not if it is only for one 1.5mm T&E cable. You can get two 2.5 T&E and a

10mm earth down one 20mm pipe with care. You certainly would not get them round any bends though.

Adam

[me]

Spot on - I was intending to use it with conventional PVC insulated t&e - what is the problem - tight fit?

[John Rumm]

If it is just one 1.0mm^2 then there won't be a problem. The more, or the thicker the cable(s) the harder it gets.

If needs be, assemble the conduit onto the cable rather than trying to thread the cable through the completed conduit.

[Nick]

On the subject of conduit.... what is the recommendation / regs regarding conduit for outside lights ?

The conduit would all be above ground by about a foot or two and largely in view, so no risk from spades / digging, and probably too big for the jaws of a hedgetrimmer - I would prefer to use plastic as it won't rust / need painting and can't "become live" if there was such a fault... but what are the ins and outs / regs stipulate ?

Thanks, Nick

[David Hansen]

On Sun, 18 Jun 2006 21:24:15 GMT someone who may be "Nick" wrote this:-

Don't attach it to a fence.

Make it waterproof, but so that any water can drain out at the lowest point(s).

Consider the effects of flora, fauna and sunlight.

Ensure cables can be drawn in properly.