Adding sockets into garage

Discussion in 'Electricians' Talk' started by tomosap, Jun 30, 2016.

  1. tomosap

    tomosap Member

    Hello all,

    Firstly, apologies if this question has been asked to death, I did do some searching but only found a thread which referred to adding sockets as a spur, but I think my situation is different.

    I have a garage attached to the house which has 1 socket and 1 light. I believe these form part of the downstairs ring as there are two cables running into the single socket on the wall.

    What I would like to do is extend this so that the single socket stays as it is (it will become an outside socket with built in RCD - do they exist? I think they do), and then add two double sockets in addition to this single socket to be placed elsewhere in the garage.

    Is this a simple case of splitting the existing input to the existing socket, or is there a more complex arrangement required?

    Thanks in advance,
    Tom
     
  2. tina lucinda lane

    tina lucinda lane Screwfix Select

    split it then link the two new ones in a loop back with this old one to create a dog leg ring or better yet take one of the two leads and wire it to the last of the two new sockets then link that to the next then back to the single socket (called extending a ring main) get a spark in tho to make sure the total area servered is not more than the cable size limits
     
  3. Coloumb

    Coloumb Screwfix Select

    You will also need to provide RCD protection to your newly installed extra cabling unless it's all surface mounted. Sockets will need RCD protection in any case.
     
  4. tina lucinda lane

    tina lucinda lane Screwfix Select

    thanks forgot about that silly me
     
  5. tomosap

    tomosap Member

    Thanks for the responses gents, appreciated.

    So based on what you're saying Alex, I've come up with the following (rather crude) diagram just to see if I've understood you correctly?

    Also, Coloumb, all the cabling will be surface mounted so when you say RCD protection, where should this go (if applicable)?

    Thanks,
    Tom
     

    Attached Files:

  6. tina lucinda lane

    tina lucinda lane Screwfix Select

    thats what i call a dog leg ring (best way is to extend the ring by extending one of the cables from the current socket to the 1st new socket then from socket 1 to socket 2 then from socket 2 back to the single socket) but as said make sure the total area covered is not more than the cable rating also make sure that the ring is covered by an rcd (as rcd socket faces can cost £50+ each)
     
  7. tomosap

    tomosap Member

    Ok, so it looks like I've got the jist of what you're saying :)

    I'll speak to an electrician about getting the dimensions checked, but I'd anticipate adding no more than an additional 10m of cabling at the absolute most. The garage is 17' x 9' and I'm only taking the cable from one wall to the wall adjacent.

    As for the ring being covered by an RCD, the house is almost brand new (built and signed off last October) and the main consumer unit has trip switches that feed all points in the house, so presumably that's what you mean and it should be ok right?

    Thanks,
    Tom
     
  8. tina lucinda lane

    tina lucinda lane Screwfix Select

    should be ok then a spark will know better tho
     
  9. tomosap

    tomosap Member

    Looking at this again, so reviving it rather than starting a new thread...

    I’m looking to add 8 sockets in total to the garage.

    The wiring is still as described above with no change, still 2 cables running into the current socket.

    Above it talks about installing RCD protection. Do I need to install an RCD in a box at the end of the two cables, then feed the 8 sockets?

    Apologies if it’s a daft question? I’m not looking to wire it up myself, but would like to know so I know how to route all the cabling and what equipment to buy.

    Thanks,
    Tom
     
  10. Jimbo

    Jimbo Screwfix Select

    If you have a RCD protection on this circuit in your consumer unit already then nothing further is needed.

    if you have an ancient consumer unit with no RCD protection, probably a good idea to get that changed tbh then the spark would be able to just get these sockets done too maybe.
     
  11. tina lucinda lane

    tina lucinda lane Screwfix Select

    I would recommend a second rcd in the garage to provide separate protection for the garage and help avoid triping the whole or part of the house circuits from triping out
     
  12. kirkdx

    kirkdx Active Member

    How far away from the consumer unit is your garage?

    When I was adding extra sockets into my garage I got the electrician to actually add it onto it's own ring main, with it's own MCB (none of the sockets are outside though). Depending what's in your garage, i.e what tools you use, and what you have plugged into the downstairs ring, you might find that adding a further 8 sockets to an existing ring is going to draw too much and cause the MCB of the existing ring to trip fairly often.

    I'm sure an electrician can provide other options if the consumer unit as no spare capacity or is too far away to easily run a new cable to, but this is the one that was strongly recommended to me
     
  13. It is not a good idea to have two RCD'S in series, design and carry out the job properly.
     
    Hans_25 likes this.
  14. Comlec

    Comlec Screwfix Select

    Hans_25 likes this.
  15. Hans_25

    Hans_25 Screwfix Select

    If you're not doing it yourself, why do you think you're best placed to decide what components are needed when the Spark "wiring it up" will need to sign off the design, installation and testing of said circuit?

    Seek professional advice.
     
  16. tina lucinda lane

    tina lucinda lane Screwfix Select

    trust me at one time this was quite possible using different trip mili amp ratings now its more difficult but still possible
     
  17. Blue89

    Blue89 New Member

    Just to point out that although ring final circuits are common, 2 cables entering a socket does NOT necessarily mean it forms part of a ring
     
  18. tomosap

    tomosap Member

    Didn’t realise this thread got some action, so will seek to address some of the comments...

    Garage is attached to the house. MCB has RCD protection on it already to the downstairs.

    Had two electricians out, both of which said that adding additional sockets should be fine and they were happy for me to run cabling based on what they saw of my existing work so no issues there.

    Both said that there was no need for additional RCD on the garage supply as there was no external cable.

    Hope that helps
     
  19. Hans_25

    Hans_25 Screwfix Select

    Even if there was an external cable, still wouldn't need additional RCD protection.
     

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