F shape extension power lead build

Discussion in 'The Projects Forum' started by Upex, Oct 22, 2015.

  1. Upex

    Thread Starter Member

    Nov 10, 2013
    67
    3
    Hi all,

    I want to build a power lead extension for 2 sheds, that will basically form an F shape. The lead will run down the fence and then to the right (longest leg and top fork of the F) but I want to also spur off half way down the longest leg (the lower fork of the F) if you see what I mean?

    Currently have 2 separate extension leads, 1 to each shed, but looking to tidy it up.

    My questions, which I hope you gurus can help with, are:

    What cable is best to use? I've looked at artic grade which seems ok and armoured but that seems excessive (there is no risk of it being cut etc, the fence isn't by a hedge etc).

    Whatever cable this transpired to be, will it be suitable to leave 'out' all year round?

    To make the spur off the main line, I assume its just a case of a waterproof junction box type connection, feeding live off live, n off n and linking the earth to earth?

    Protection - the lead will run from a standard switched house socket, and is on an rcd circuit, but should I also use a plug in rcd at the socket, or a fused switch at the house end etc, or are these not needed as on an rev circuit anyway?

    The longest leg (top of F) will be 50m, and Usage will be for some low power led lights (200w max if all on at the same time), 2 x 100w heater lamps and I want to add a couple of sockets (low use like charging a drill or battery charger etc) with the largest draw being 800w drill. Unlikely to be drilling whilst needing lights etc, but assuming I have everything on all at the same time (won't happen,but playing safe) I get a max draw of 1.2kw, so assuming 1.5kw to be safe, I think a 2.5mm csa cable would be a suitable size?

    Any other things I need to think about, or consider etc, plus any suggestions and corrections would be great.

    Thanks, Upex
     
    Last edited: Oct 23, 2015
  2. sirch2

    Well-Known Member

    Jan 21, 2013
    1,008
    351
    What country are you in? You should comply with local regulations but generally anything outside should be armoured.

    Ideally you would come off a separate breaker on the consumer unit but at least a double pole fused switch at the house end, no point in a separate RCD but if there is a fault on the cable/sheds then you want to be able to isolate it to prevent tripping of the main RCD.

    I would have thought it would be better to run the cable to the first shed, terminate it inside the shed and then run a cable from there to the second shed. It may well be worth getting a "garage" type consumer unit, they usually have two breakers and an RCD, and fitting that in the first shed.
     
    Upex likes this.
  3. Upex

    Thread Starter Member

    Nov 10, 2013
    67
    3
    Hi sirch,

    I'm in UK. Do you know if ill need some sort of certificate etc? I thought that by just plugging it in a normal socket that certs wouldn't be needed.

    Good shout about the shed panel etc, although its not ideally placed to do as you say, I could use a 3rd little shed that's near the bottom of the F, mount a board in there with 2 rcds, then have 1 run to shed, and the other run to other shed, that way each on there own breaker and although the power is coming from plug socket in the house, the lights and sockets in shed have a closer breaker.

    My isolation is to use the switched plug in the house, or to plug the plug out the socket on the house presently, but the switch in the shed is a good idea, although if have breakers as above, would the switch still be needed?

    Appreciate that armoured cable would be best, but I really don't think the additional cost is worth it for this use, especially as the green gets shifted round every few years and ill need different run length of cable again etc. And it gets very little use in summer (I currently for the extensions in and bring out when needed in summer, but leave out in winter.

    Thanks for your input, much appreciated.

    Upex
     
  4. blocco a spirale

    AAC Fanatic!

    Jun 18, 2008
    1,438
    368
    If you power the sheds from a 13A plug fitted in a socket in the house, you don't need to notify anyone and you don't require an inspection or certificate as it is not considered to be a fixed installation.

    Test the cable assembly with a meter before you plug it in and check the final installation with one of those little test plugs that indicate whether or not the sockets have been wired correctly and continue to do this regularly.

    http://www.screwfix.com/p/lap-ms6860d-socket-tester/91596

    Cable:
    http://www.theelectricalwholesaler....-Yellow-3183AG-3-Core-1-5mm-2-5mm-4mm-Caravan
     
    Last edited: Oct 22, 2015
    Upex likes this.
  5. sirch2

    Well-Known Member

    Jan 21, 2013
    1,008
    351
    As said above if you just plug it in then you don't need anything by way of certificates etc. Also as I said there is little point in having additional RCDs if the socket you are using is already protected by an RCD. There is no saying which one will trip first.

    The main reason I suggested running it into the first shed and then spurring off that into the other was to keep the junction out of the weather, even the best sealed things get condensation in them after a few years. That said you should get a good few years out of a decent quality IP67 rated junction box if you install it correctly.
     
    Upex likes this.
  6. #12

    Expert

    Nov 30, 2010
    16,257
    6,757
    I feel an objection to laying a power wire on the ground and leaving it there for years. It will either survive, or it won't. If it doesn't survive, the way in which it fails can be a danger to people. That is why I always use the correct cable and bury it according to the proper electrical codes.
     
    strantor likes this.
  7. strantor

    AAC Fanatic!

    Oct 3, 2010
    4,302
    1,988
    What is being described here is a half-ass.
    Don't half-ass. Either go full-ass, or no-ass.

    If laying wires on the ground is OK with you, then why not use extension cords as you're already doing? (no-ass).
    I don't see what you seek to gain by repeating the exact same setup, but with attic wire instead of extension cord.

    If extension cords aren't kosher for your taste, then you should do it (or have it done) right, with buried lines on a dedicated breaker. (full-ass).

    Here's another idea that's greater than no-ass, but less than half-ass:
    Put some poles by the sheds and run some wire rope between the tops of the poles. So, make your "F" out of wire rope lines in the air, a good couple feet above head-height, and then wrap your extension cords around the wire rope.
    That way they're up off the ground where dogs, lawn mowers, and toddlers might chew on them, they look semi-professional (especially if you use black UV-resistant extension cords), and you don't need to know a damned thing about 'lectricity to do it. You don't need to touch a single wire, just plug & play, no permits needed, no potential code violations, no haphazardly engineered non-GFCI protected dangerous nonsense, no impediment to pedestrians.
    It looks like a win-win-win from where I sit.
     
    #12 likes this.
  8. sirch2

    Well-Known Member

    Jan 21, 2013
    1,008
    351
    @strantor its a cultural thing. One of the things that struck me most on my few trips to the USA is the way you guys just love to hang things off things, streets littered with cables, traffic lights strung across junctions, fishing rods (poles?) hanging off the front and back of trucks. We just don't unless we have too and there are active programs to bury many of the above ground power lines, especially in scenic and rural areas.

    So while you and #12 have made some very valid points and regardless of the quantity of ass involved :) I imagine Upex and certainly if he listens to SWMBO, will not be stringing anything across the garden.
     
    Upex likes this.
  9. strantor

    AAC Fanatic!

    Oct 3, 2010
    4,302
    1,988
    Sounds like your trips to 'Murica and India have crossed paths in your mind LOL.

    So what do you guys do with Christmas lights? Spool them out into a pile on the lawn? Stack them neatly on the porch? Surely you hang those... right? ;)

    Enough jokes now, it seems if OP were willing or able to trench out and bury the lines, he wouldn't be on here asking for ways around it (it, being the obvious right answer, to bury the lines). So if burial is out of the question and the current solution is out of the question and OP's only thought (attic cord across the garden floor) is just a repeat of the the current solution, then what does that leave?
     
    sirch2 likes this.
  10. #12

    Expert

    Nov 30, 2010
    16,257
    6,757
    My street and a street in India:
     
  11. joeyd999

    AAC Fanatic!

    Jun 6, 2011
    2,675
    2,721
    We have to keep our campers behind a setback.
     
  12. #12

    Expert

    Nov 30, 2010
    16,257
    6,757
    If only that had anything to do with wiring it would be relevant to this thread.
     
  13. Upex

    Thread Starter Member

    Nov 10, 2013
    67
    3
    Thanks for the input all, and education on Indian wiring?

    To be clear though, I'm not proposing to put cable on the ground, I want to replace the cable to avoid this. It would be mounted alone a fence, at about 2-3 foot off the ground. The fence isn't on the edge of property and there is no risk of damage to the cable whilst on the fence, baring a freak plane crash or something (ie its not near a hedge to be trimmed through, its not near the carriageway or other access etc).

    I'd much prefer to bury and do properly of course, but it'll be up for a couple of winters then taken down and moved around to another shape and length etc. Presently the extensions are laid on the floor when used, I just want to have the same easy service but tacked to the fence so is tidy, safer (from tripping and standing on etc) and in a type of cable that can stand to be left out better than a normal flex can etc.

    I could tack the extension and be done with it, but I thought there maybe a better cable choice and opportunity to make a bit tidier whilst at it, e.g. by doing the consumer unit in shed type idea as above, and fitting sockets and light switch to the walls, rather than plugged into an extension real.

    I do appreciate that many electricians will be balking at the idea, but alas a full ass cable burial is far too costly and too permanent for what I need. Trying to establish a better cable to be left out is, in my view, not a bad thing and can only make the existing no ass solution a little more robust?
     
    strantor likes this.
  14. strantor

    AAC Fanatic!

    Oct 3, 2010
    4,302
    1,988
    Ah, well then in that case check out SO-cord. SOOW or SJOOW should work just fine, and you can put the screw tightening plugs on it. 3 conductor 12awg or 14awg. Of course you'll need to consult the AWG-metric table.

    ...wait, SO-cord is "a thing" in the UK, right? I'm sure they have it even if it's not called "SO-cord."
     
    #12 likes this.
  15. #12

    Expert

    Nov 30, 2010
    16,257
    6,757
    Exactly the kind of thing that stops me. I never know when I'm calling out a Trade Name that doesn't exist in another country.:(

    Oh well. The Brits will be up in 6 to 8 hours and they can clear this up for us.;)
     
  16. Upex

    Thread Starter Member

    Nov 10, 2013
    67
    3
    I can't seem to find these listed under the UK stores, not under the soow type names anyway.
     
  17. #12

    Expert

    Nov 30, 2010
    16,257
    6,757
    Well, SO cord is a very flexible cable often used for tools like a wet&dry vac or a Sawzall. Black, thick, abrasion resistant.
    What you call it in England is often a mystery in the colonies.
    When the lift stops, check the boot of your lorry...:confused:
     
  18. sirch2

    Well-Known Member

    Jan 21, 2013
    1,008
    351
    It's your call but that Arctic cable @blocco a spirale linked to might be as good as anything. It is commonly used for camping and caravaning.


    BTW, my recollection of Murican streets is a bit more

    [​IMG]
     
    Upex likes this.
  19. strantor

    AAC Fanatic!

    Oct 3, 2010
    4,302
    1,988
    While waiting in the car for daughter to pick out a Halloween costume (abt 45 min) I tried to find the UK/EU equivalent of SO cord. My Web search skills were inhibited by my allegedly "smart" phone, so maybe I got less than fair shot of finding it; I found NOTHING resembling a direct equivalent STANDARD product. I found some products that met the same specs as SO cord but they were not standardized across manufacturers, they were called different things by different parties, were hard to come by, and prohibitively expensive. I found most close relatives by googling "flexible trailing cable " and "elastomeric multiconductor cable ".

    Since SO cord seems to be a non-thing over there (which I can't wrap my head around since it's so common here, someone please prove me wrong), what you need to find is a cable that's UV and weather resistant. The Arctic cable mentioned earlier does not say anything about UV resistant. Maybe it is, I don't know. If I had time I'd dredge up the VDE or whatever standard on it and see. Maybe you can do that, or just find a product that explicitly states UV resistant.

    One thing that usually IS UV resistant (at least here in America - a caveat I guess I'll need to start adding to almost everything I say on this forum) is extension cord, which you already have. Why not just staple the extension cord to the fence?
     
    Upex likes this.
  20. strantor

    AAC Fanatic!

    Oct 3, 2010
    4,302
    1,988
Loading...