Conduit drops: junction or loop?

[Alexander Lamaison]

When wiring PVC conduit drops to sockets on a radial circuit, would you loop the singles down the drop to the socket, then back up and on to the next? (i.e. 6 singles in the drop conduit)

_______ ______________ ______________ _______ ========. .================. .================. .======== ||| ||| ||| ||| ||| ||| ||| ||| ||| ||| ||| ||| ||| ||| ||| ||| ||| ||| SOCKET SOCKET SOCKET

Or would you make a junction using chockblocks in a BESA box at the top of the drop? (i.e. 3 singles in the drop conduit) ___ _______(...)_______________(...)_______________(...)________ =======|HHH|===============|HHH|===============|HHH|======== ||| ||| ||| ||| ||| ||| ||| ||| ||| ||| ||| ||| SOCKET SOCKET SOCKET

Or does it really not matter?

Thoughts appreciated. Alex

[Andy Wade]

The former, unless you're desperate to save on circuit length / voltage drop / Zs. Otherwise the solution involving fewer joints is preferable. Also there ain't a lot of space in a 20 mm round conduit box for connecting nine 2.5 mm^2 wires - you'd need to use adaptable boxes for that.

[harry]

a radial circuit, would you loop

rop to the socket, then back up and on to the

e. 6 singles in the drop conduit)

________      ______________      _______

===============.  .================.  .========

||  |||            |||  |||            |||  |||

||  |||            |||  |||            |||  |||

||  |||            |||  |||            |||  |||

SOCKET              SOCKET              SOCKET

ld you make a junction using chockblocks in a BESA box at the top

it)

__________(...)________

|===============|HHH|========

  |||                 |||

|||                 |||

                |||

              |||

         SOCKET

oughts appreciated.

Windows Explorer

will f ind it hard to pull the six wires down a single conduit e ven if quite short. Can be done but you need to keep the wires exactly parallel, straight and no twists.

[Alexander Lamaison]

Hmmmm. The conduit factor calculation suggests I'm well under the maximum of 11 cables.

6 x 43 = 258 < 460

I guess the proof is in the pudding.

Alex

[fred]

In case it helps, I've previously seen a plastic conduit run much as you describe and the installer had used 2.5mm2 twin & earth instead of singles and at the drops (of about 1.5m) had stripped back the outer to leave the insulated singles and had sleeved the earths. I thought it was quite a neat way of doing it and I assume it was because T&E is relatively cheap. It looked like there was plenty of room in the 20mm for the 6 cores, albeit 2 were in floppy sleeves.

[Alexander Lamaison]

Interesting approach. I assume only the drops were in conduit, and the T&E was cliped up round the ceiling?

I'll be using conduit all the way back to the CU so I'm using singles. They're more flexible than T&E, which I'm hoping makes them easier to draw in.

Alex

[fred]

It was all in conduit but it was a semi industrial location with long straight runs so I imagine they went in quite easily. Approx 4m between sockets so 8m or so pulled in leaving 2m each end to be stripped and dropped down as singles. Standard round junctions in the horiz line above the drops.

Prob easier if you have a lot of bends.

[Alexander Lamaison]

What's a good poor-man's cable lube? Will talc do?

[Tim Watts]

On Wednesday 20 March 2013 18:03 Alexander Lamaison wrote in uk.d-i-y:

I've used talc once - it seems to do the job.

[Alexander Lamaison]

Good enough for me. Thanks.

Alex

[harry]