Underground Cable Ducting

[Chrisgr31]

I am looking at replacing the patio but before I do so I want put in ducting for electricity to light the patio and to my shed and greenhouse.

My thoughts are to have an initial duct from the garage to the edge of the patio where I plan a small shed containing a junction box and from there ducting to the separate locations.

When I installed a duct to allow the installation of a fibre internet cable the guy installing the cable complained as the duct was corrugated it was difficult to get the cable through. However most ducting appears to be corrugated.

So will I regret using a corrugated duct

[cml24]

Yes, you'd regret it. Get something like the below. Twinwall with internal wall smooth.

https://unitedcivilssupplies.co.uk/products/137-16...

[cml24]

Probably a smaller diameter for your use is more appropriate!

[megaphone]

You can get stuff that is corrugated on the outside and smooth on the inside. 'Twin Walled"

Eg. https://www.tlc-direct.co.uk/Products/FXKVR50.html

[Sylvias_Father]

Make sure that you get smooth bore. They are ribbed on the outside (to give them strength) but the inner is smooth.
(Likely to cost more thought)

https://www.pdmltd.co.uk/products/civils-landscapi...

[megaphone]

Or depending how many cables you are running , blue MDPE water pipe makes a good conduit. It is tough and smooth.

[dhutch]

megaphone said:

You can get stuff that is corrugated on the outside and smooth on the inside. 'Twin Walled"

Eg. https://www.tlc-direct.co.uk/Products/FXKVR50.html

This

[Mr Pointy]

Here you go, lots of colours, lots of sizes:

https://www.mjabbottdirect.co.uk/Products/DUCT,-PI...

[gtidriver]

I just had a large patio laid, I ran a couple of lengths of 2inch waste pipe from the house to outside our fence line, our bbq and bits will be infront of the fence so access will be fine, im also planning on a cctv upgrade and have run 22mm conduit from the corner of the house under the patio and then finishing next to the garage. I laid some lengths of old angle iron on top of them for protection.

[Chrisgr31]

Thanks all. I get the message!

[theboss]

50mm twin walled just as linked above would be perfect.

I buried ducts of various sizes between points on my plot when ground work was being done, the larger stuff is great if you need to pull really heavy cables and the ends are concealed / out of sight, but 50mm is probably the sweet spot between being easy to bury and discrete but still having the capacity to put whatever you think you need now, and still having the ability to pull something else through in the future.

If there's space and you bought more than you need, chuck a second one in for good measure!

[Belle427]

If you install draw ropes when putting it in and after cables are pulled its not really a big problem but smooth certainly is easier.

[gtidriver]

Double edged sword running conduit though, the wife knows its there and she's having ideas of what else could now go to the other side of the garden, sink with running water was one thing, I just think more work for me..

[Snow and Rocks]

What sort of length are we speaking about?

I recently run water, electricity and data through ~90m of 80mm corrugated stuff linked below. Despite it being corrugated internally and around various corners, it was relatively easy to pull through.

https://store.jdpipes.co.uk/80mm-unperforated-land...

What makes the difference is having a decent sturdy pull cord run through so that you can guide it through any sticky spots.

I used a leaf blower and a ball of tissue to pull light twine through before then putting in a long line of strong polyprop rope. Some ducting has preinstalled lime but I would always replace it with stronger stuff that won't easily rot.

[LooneyTunes]

Consider the size of cables, length, bend radii, and distance before deciding what size to go for.

Cables that would easily fit in say 63mm duct might not go round corners anywhere like as easily as they would in a 110mm.

Don’t forget too that as soon as you have a sock or bundle of rope/tape connecting your draw line to the cable, that adds to the overall diameter and will be harder to bend round corners.