earthworks/lay cable now for Part P electrician to install later

Discussion in 'Electricians' Talk' started by egamar, Jul 3, 2019.

  1. egamar

    egamar New Member


    I am having some garden landscaping done in a fortnight with a view to installing a pond and a deck later in the year.

    The'site clearance' (removing leylandii stumps etc) and installing new fencing will be done in a fortnight, but the pond build will not start until October.

    I would like just to run a length of appropriate cable from the house end to the pond end (maybe 22m) while the landscaping is being done, leaving a suitable length of cable at either end for the Part P electrician to do what he needs to do to connect into the "house" and provide the necessary socketry in the garden. All I want to do is get the cable in place while the landscapers are on site.

    The "ideal" route (from my uniformed perspective) would be along the new fence line - concrete posts with 12" gravel boards) - at ground level snug to the concrete posts and gravel boards. A path will be constructed above the cable along the line of the top of the gravel board - so 12" or so above the cable. I'm happy to lay it in a conduit if necessary.

    i just don't want to have to dig everything up once the landscapers have finished!

    the supply would need to support a pond pump, a bit of outdoor lighting, and some electrical garden tools (hedge trimmer sort of thing) rather than running a long extension cable from the house.

    I'm not trying to shave pennies off the job here, I just want to get the sequencing right and not have to dig up a path or a flower bed that the landscapers have painstaking created.

    So I would really appreciate advice on:

    - cable routing - is what i'm suggesting OK, if not - what is the right way?
    - what sort of cable should I run?
    - should it go in a conduit?

    very many thanks!
  2. Get the Electrician round and discuss the job with him.
    He will then tell you what size cable he wants and where he wants it,he might supply the cable and warning tape or let you supply it.
    After you have laid the cable he can then inspect it,before it is covered in.
    It is his name on it,so do what he asks to get mim to finish the job and certify.
  3. egamar

    egamar New Member

    Ack: thanks! You make obvious sense, but I don't know which electrician will do the job!

    I haven't got that far in my planning/thinking process, and I don't want to get someone round to give me a quote and what-not and waste their time by giving the job to someone else later on if the nature of the job changes a bit after the blokes have built the pool.

    I appreciate why you're saying what you're saying, but I don't mind paying for a longer/higher-spec cable than might be recommended.

    Perhaps a silly question - but mightn't the electrician be able to 'test' the cable rather than actually looking at it before it's buried?

  4. ajohn

    ajohn Screwfix Select

    I'd suspect your best option would be to lift the path when the cable is needed and the things it needs connecting to are available. If the path is needed before this you could still bear lifting it in mind. Eg just put it in place.

    Reason - buried cable needs to be laid at a suitable depth to avoid damage. There isn't a specific requirement except in certain circumstances, When laid though there must be a warning tape above it. General idea is that if some one does dig they will notice that before hitting the cable, Without the path over it a guess depth would be in excess of 300mm in case a spade or fork is used in the area.

  5. Tony Goddard

    Tony Goddard Screwfix Select

    You could go with a 10mm2 3 core SWA cable, this would be over specced but give you plenty of scope for what to run off it, and it's not hugely expensive. Would satisfy anyone I would think.

    The electrician can test it in situ (for insulation resistance, continuity etc.) when the time comes.
  6. andyscotland

    andyscotland Active Member

    If you do run the cable before speaking to a spark I'd take photos of the whole run, showing it in the trench (with a marker/measuring tape showing the depth), and then separately with the first bit of backfill and warning tape. Otherwise the electrician can test the electrical properties of the cable but you're asking them to take the physical installation (which they're also responsible for) on trust.

    Another idea might be to just run a proper underground duct with a rope through it (again photographing the depth etc) and then the spark can pull in whatever cable they want to use. Also means you have the option to replace the cable in future if there's any kind of problem.
  7. egamar

    egamar New Member

    Thanks Tony Goddard and Andy Scotland. Exactly what I needed! I'm not sure which of the two solutions I'll use, but the suggestion of taking photos makes so much sense!

    SWA cable is what I was thinking of, and you're right - it's not hugely expensive.

    A conduit of scaffold poles should work :) (Only nearly joking).

    Thanks all who contributed.
  8. Tony Goddard

    Tony Goddard Screwfix Select

    Andyscotlands suggestion of a conduit is a good one, if anything ever goes wrong, needs upgrading, or you want to run an additional cable, makes it easy - and then its all buried out of sight.
  9. sospan

    sospan Screwfix Select

    As stated before put some trunking in the ground and leave a couple of draw wires in it. Then when you get an electrician in to do the work, he can pull the desired cable through. Just remember to cover each end to stop debris falling in.
  10. andyscotland

    andyscotland Active Member

    I'd go for proper (plastic) underground ducting. Anything metal would need to be correctly earthed along the complete length. Plus from experience, a badly deburred end of metal pipe cutting through your draw string as you're pulling in is only slightly more fun than an equivalent end cutting through and subsequently shorting the cable sheath. Though at least easier to dig it back up than get at it in a finished wall :(
  11. sospan

    sospan Screwfix Select

    Ah earth the continuous pipe in the ground to ground ;)
  12. Tony Goddard

    Tony Goddard Screwfix Select

    I've seen scaffold tube and joiners used as a conduit before on an instal done in the 60's, it had survived well and of course is very, very strong, the main issues are the risk of the cable catching on a burred edge and bending it to rise to the surface. The regular flexible plastic tube used by all and everyone is much better and I would think cheaper than even second hand scaffold tubes.
  13. Bazza

    Bazza Screwfix Select

    As above. Install service duct 450mm minimum deep with appropriate warning tape, etc.
    These guys sell the ducting by the metre.

    Attached Files:

  14. egamar

    egamar New Member

    "regular flexible plastic tube used by all and everyone"

    see, I'd thought metal = stronger = better. What do I know? which is, of course, why I asked :)

    Many thanks again to everyone - it's really appreciated.
  15. ajohn

    ajohn Screwfix Select

    SWA cable would be used. It has a very slow spiral steel closely wound wire reinforcement around it under a plastic cover. That is connected to earth. Your electrician might use either 2 or 3 core versions of it, That and size depends on distance and load. If it's a new circuit other things may need doing based on the current state of your existing electrics. Maybe not if it isn't. You should also get a certificate when the work is done.


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