What size armoured cable for greenhouse electrics?

Discussion in 'Greenhouse Growing' started by Sheps, Apr 21, 2017.

  1. Sheps

    Sheps Keen Gardener

    Joined:
    Mar 30, 2017
    Messages:
    382
    Gender:
    Male
    Location:
    West Yorkshire
    Ratings:
    +1,101
    Hi everyone,

    I'm going to buy all the bits for my greenhouse electrics in the coming days, so can anyone please tell me what size armoured cable would be best for the job?

    The job will be carried out by a qualified electrician once I have bought all the bits.

    Thanks

    Sheps.
     
  2. Hex_2011

    Hex_2011 Gardener

    Joined:
    Apr 8, 2011
    Messages:
    194
    Gender:
    Male
    Ratings:
    +134
    Cable size will depend on what you plan to run off it and how long the cable is. Cable length affects the voltage drop. This calculator will give you some idea but always best to double check with the sparky before buying
    Voltage Drop Calculator | TLC Electrical
     
    • Like Like x 2
    • Agree Agree x 1
      Last edited: Apr 21, 2017
    • HarryS

      HarryS Eternally Optimistic Gardener

      Joined:
      Aug 28, 2010
      Messages:
      8,906
      Gender:
      Male
      Occupation:
      Retired
      Location:
      Wigan
      Ratings:
      +16,246
      Check with your electrician on the SWA cable size . For the cable , glands , waterproof socket etc etc go to a good electrical factor . This should be cheaper than going to the big sheds. Screwfix prices will be good , but not sure they sell SWA by the metre ?
       
      • Like Like x 1
      • JWK

        JWK Gardener Staff Member

        Joined:
        Jun 3, 2008
        Messages:
        30,678
        Gender:
        Male
        Location:
        Surrey
        Ratings:
        +45,618
        Personally I'd let the sparky buy everything, they know what they need and saves you having to do the sizing calculation from scratch. Plus they will probably be able to buy it all cheaper from a factor.
         
        • Agree Agree x 3
        • Like Like x 1
        • Scrungee

          Scrungee Well known for it

          Joined:
          Dec 5, 2010
          Messages:
          16,524
          Location:
          Central England on heavy clay soil
          Ratings:
          +28,996
          Do you have a spare way in your consumer unit for this circuit?
           
          • Like Like x 1
          • Sheps

            Sheps Keen Gardener

            Joined:
            Mar 30, 2017
            Messages:
            382
            Gender:
            Male
            Location:
            West Yorkshire
            Ratings:
            +1,101
            Thanks for the advice, it's appreciated...I think it might be best leaving it to the Sparky :blue thumb:

            Hi Scrungee...yes, I have spare ways in the CU in the house and in the old type fuse box in the garage, I was planning on having the power supply to the greenhouse coming from the garage fuse box, but now that I think about it I might have to have the old fuse box changed out for a new CU before the Sparky will even think about doing the wiring for the greenhouse :yikes:

            Think I might have started running before I could walk on this particular job :redface:
             
            • Agree Agree x 1
            • Scrungee

              Scrungee Well known for it

              Joined:
              Dec 5, 2010
              Messages:
              16,524
              Location:
              Central England on heavy clay soil
              Ratings:
              +28,996
              Are they RCD protected?
               
              • Like Like x 1
              • Sheps

                Sheps Keen Gardener

                Joined:
                Mar 30, 2017
                Messages:
                382
                Gender:
                Male
                Location:
                West Yorkshire
                Ratings:
                +1,101
                The Consumer Unit in the house is one of the new, 17th edition, metal types and has dual RCD's, with the power supply for the garden / garage running off this on its own MCB.

                So, with that being the case, is the old type fuse box ( pull out plugs with fuse wire ) in the garage protected by RCD? or does this still need replacing with a new one with its own dedicated RCD.
                 
              • Vince

                Vince Not so well known for it.

                Joined:
                Mar 10, 2008
                Messages:
                1,861
                Gender:
                Male
                Occupation:
                Retired
                Location:
                North London / Lincolnshire Fens
                Ratings:
                +3,499
                Best not say what I do, but it works!:snorky:
                 
                • Like Like x 1
                • Sheps

                  Sheps Keen Gardener

                  Joined:
                  Mar 30, 2017
                  Messages:
                  382
                  Gender:
                  Male
                  Location:
                  West Yorkshire
                  Ratings:
                  +1,101
                  When first thinking about it I probably had a similar idea, Vince :yikes:...mine was heavy duty rubber pond cable, plug on one end and a waterproof socket on the other, running through some black flexible conduit and into a circuit breaker in the garage :hapfeet:

                  But in the end I thought I better have it done all legal like.
                   
                • ARMANDII

                  ARMANDII Low Flying Administrator Staff Member

                  Joined:
                  Jan 12, 2019
                  Messages:
                  48,096
                  Gender:
                  Male
                  Ratings:
                  +100,834
                  I bought all the electrical gear and armoured cable for installing into my Observatory and carried out all the work fitting it. I'm an ex-RAF Radar Technician and so my certification still stands despite the recent changes in the qualification system. But, even so, I had a friend who is also a qualified working electrician to check my work as it never harms to do so. I'd definitely make sure that the power source is RCD and any sockets you installed are "weather proof" and also RCD.:coffee::snorky:
                   
                  • Like Like x 1
                  • Sheps

                    Sheps Keen Gardener

                    Joined:
                    Mar 30, 2017
                    Messages:
                    382
                    Gender:
                    Male
                    Location:
                    West Yorkshire
                    Ratings:
                    +1,101
                    Thanks for the advice, Armandii...I'll make sure that RCD's are fitted.
                     
                    • Friendly Friendly x 1
                    • HarryS

                      HarryS Eternally Optimistic Gardener

                      Joined:
                      Aug 28, 2010
                      Messages:
                      8,906
                      Gender:
                      Male
                      Occupation:
                      Retired
                      Location:
                      Wigan
                      Ratings:
                      +16,246
                      For my outside electrics I have RCD protection for each of the three circuits . Last year my new kitchen electrics were fitted and certified by an electrician , we also fitted anew consumer unit.
                      I asked him that with the modern breakers fitted in a CU do I still need RCD protection for my outside electrics ? The answer was not really but it does no harm to have double protection .
                      So do you need RCD protection for outside electrics ?
                       
                      • Like Like x 1
                      • ARMANDII

                        ARMANDII Low Flying Administrator Staff Member

                        Joined:
                        Jan 12, 2019
                        Messages:
                        48,096
                        Gender:
                        Male
                        Ratings:
                        +100,834
                        I think the answer to that, Harry, lies in my left hand where the shape of a male/female connector was burnt to the bones of my fingers and palm of my left hand. Many years ago, while abroad, I was called straight from servicing an aircraft to repair some machines in a Commcen. When getting there I noticed that someone had left a wired connector lying on the floor of a working area. I picked it up only to have it fall apart in my hand.........I still have the scars after all those years and I can still remember the smell of my burning hand. So, you can understand why I trust no one's work but mine and have the greatest respect for electricity.
                        Electricity is not like water or gas. You can't see, smell it, hear it, or taste it.............but you can feel it.
                        You can do electrical work yourself, if unqualified, but you do have to have a professional electrician check and verify your work. That is not as easy as it sounds as most electricians won't verify the work and will want to do it themselves.
                        If the sockets are going to be outside, including in a Green House, then they need, in my opinion, to be doubly safe and going the extra mile to install weather proof RCD sockets is something you won't regret. There is the possibility of other members of the family, over time, going into the Green House and using the sockets so everything has to be doubly safe to give peace of mind.
                        I'm sure the Electrician that Shep will use will do the job to the highest safety level and decide how much he will put in, but I'm also sure the provision of weather proof RCD sockets will meet his approval as an extra safety check. I had my friend check my work as it was a long job and I was also doing several other jobs at the same time and there were several days when I had been working 12 hours on my knees or back to get the jobs done, and that's when you get tired and make mistakes. My friend wondered why I had asked him and I told him about it being a one man job . After inspection my friend grinned and told me I'd put in more safety checks that he might have done when working on a job but approved of them.
                        Are Weather proof RCD sockets necessary?.........the age old scars on my left hand make me nod my head, Harry.:dunno::coffee::snorky:
                         
                        • Like Like x 2
                        • Sheps

                          Sheps Keen Gardener

                          Joined:
                          Mar 30, 2017
                          Messages:
                          382
                          Gender:
                          Male
                          Location:
                          West Yorkshire
                          Ratings:
                          +1,101
                          I already have one of these in the garden, fastened to the outside of the garage and it has worked spot on for many years.
                          ae235.jpg
                          So, I was thinking 2 of this type in the Greenhouse would be sufficient, giving me enough sockets for a Fan, Heater, Heated Propagator and Radio, but if anyone can recommend a better type, then feel free to comment :)
                           
                          • Like Like x 2
                          Loading...

                          Share This Page

                          1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
                            By continuing to use this site, you are consenting to our use of cookies.
                            Dismiss Notice