Underground services

[Huge]

I'm starting to plan for re-running power to my workshop, which is some

35 metres from the house. This is being driven by the fact that all the electricity in there is hung off a single 13A switched fused spur from the most heavily loaded ring in the house, such that when I start the 4-post lift, the mains voltage sags so much the lights in the workshop (which are actually on a power circuit - something else to sort out) go out ...

I'm going to rerun the power as a spur from the integral garage which has its own dedicated 32A way in the CU - a complete waste, given that there are 2 twin mains sockets in there and that's it.

I was originally planning to run a single SWA cable in a trench across the concrete yard, but thinking about it, the single most painful part of this is digging up the yard (although I shall be re-opening a trench originally dug for rainwater drains, only this time refilling it properly!) It then occurred to me I might as well run a water pipe, too, so I can have a tap in the workshop. And then a phone/intercom cable. This morning it occurs to me I may as well run underground conduit and run the services through that. So ...

- Is it OK not to use SWA if the mains cable is in conduit?

- Is it OK to run mains, water, 'phone, etc., in the same conduit?

- My OCD says to run separate supplies for the power and lighting in the workshop, spurred from the appropriate supplies in the garage. Should I do this?

- The lighting in the workshop is pitiful. Are standard linear fluorescents still the technology of choice?

- Do I need any certification of all this?

- Anything else I should bear in mind?

[Chris Bartram]

I'm pretty sure you should have physical seperation between mains and phone/data, which is why you get compartmentalised trunking in offices.

[Huge]

OK, thanks. Two conduits, then?

Also, how the hell do you get the initial rope pull through the conduit so you can pull the remaining services?!?!?!?

[Huge]

SWA + conduit???

[Davey]

[Brian Gaff]

Yes Virgin has used the same bit of stuff on a neighbours system and now her phone sounds like its picking up weird digital modem like sounds all the time. It never did this before they tidied it up. I think the same rule applies to when you build things electronic all over a bench, they work perfectly, as soon as you put them in a smart box its not going to work. Besides, surely water and power need to be completely separate and given the low cost of plastic pipes these days, it seems daft to scrimp on this. as long as you keep safe what stuff runs in which bit of course! Brian

[Mark Allread]

*Before* installing the conduit drop the weighted rope/cord down the conduit when the conduit is as upright as you can get it.

Its probably worth putting a couple (at least) of small diameter cords down so that, later on, when you remember that 'this is an essential' you still have a pull-through in the conduit.

[Huge]

Cheers.

[Huge]

35 metres of it?

Yes, thanks, I was going to do that. Indeed, I was just describing the idea to my wife, who looked absolutely fascinated. Not.

[Bob Eager]

Thin string tied to a bit of cloth, vacuum cleaner?

[Bob Eager]

Mains and other stuff must be separated by a largish gap, so either partitioned conduit or just two of them.

I'd do a single sub-main and then a small consumer unit in the garage.

I'd like to know too. I'm about to do lighting in my (indoor) workshop.

[Nightjar]

Seal one end of the conduit around the hose of a powerful vacuum cleaner. Tie string to a light ball that nearly fills the conduit and feed that into the other end. Flake out enough string to suit the length of the conduit. Turn on vacuum cleaner and wait for ball to arrive at other end.

[Mark Allread]

Stand on the roof?

Sorry, I missed the bit about the length - others suggest suction; I'd try blowing a small ball with light line attached using a leaf blower with the outlet suitably adapted down and sealed to conduit.

A single run of 35m of conduit, in the diam you seem to be looking for, isn't going to be the easiest to handle (or find probably ) wouldn't you be better breaking it into shorter runs and properly jointing them together.

[Tim Watts]

Maybe tie a string to a ball of kitchen tissue and suck through with a vacuum? Or use a fish tape.

[Andrew]

You put the pull cords inside the conduit as you bury it !.

Alternatively, get some lightweight string (or even knitting wool), and affix to a ping pong ball or similar, which is a loose fit inside the conduit, then attach your Henry or Dyson to the other end and give a good suck.

dont forget to tie the other end of the string or wool to something before you start sucking.

Or borrow someones pet hamster or rat ....

[Robin]

I've seen drums of continuous conduit used often enough. And some even come with drawing tape fitted. See eg

[Robin]

I'm told a strong magnet and a large nut will pull a _thin_ (eg fishing) line through smooth-walled conduit that's flat-ish. But I've not seen it working.

[Mike Tomlinson]

En el artículo , Huge escribió:

That's a definite no-no

Physical separation required between mains and LV, so two conduits plus a separate water pipe, or SWA + conduit + water pipe.

Did you get your random RCD tripping resolved? (If you posted with a resolution, sorry, must have missed it)

I suspect that's so the lights don't also go out if the power goes off while you're working with a whizzy tool with sharp bits.

[Clive Arthur]

Use lightish string first, blow it through with compressed air. It'll go round corners and works much better than you might imagine.

Cheers

[Huge]

[20 lines snipped]

From what I've been reading, joints are something of a no-no.