Question Adding electricity to outbuilding

Discussion in 'Home Cinema Buying & Building' started by xar, Sep 30, 2017.

  1. xar

    xar

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    Not sure this is the right forum area, but is related to a wider build question. I want to put a shed outside my garage so I can fully convert the garage itself. See first picture below: the shed will run from the garage door to the end of the sand pit. In the middle of this area on the fence is a driveway light, and ideally I would want to lose the light but reuse the cabling to put electricity points into the shed. Questions are:

    - any reason that cable can't be used for plug points? I.e. lighting cable not as powerful as 'socket' cable
    - the light is the first of 6 on the drive, any reason it would stop the rest working?
    - assuming it can work, could the sparky 'make it safe' so that the shed can be installed and a hole cut for the cable without them being on site, and with cutting the power to the garage in the meantime (where the cable is wired too). I.e. the sparky would come later to fit the sockets in the shed (I ask this because getting multiple trades together at the same time / same day has been difficult in previous experience).

    Thoughts / knowledge appreciated.
     

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  2. Ambienz

    Ambienz
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    Lighting circuits would be 6 amp, power 13amp.

    A sparky would say no, but reality is you would just keep tripping fuses if drawing too much power.

    I have a low amp power outlet in bathroom running off lighting circuit. However that is for particular use, not general power.

    The fix is to run 13 amp 3core from either a fuse box or close power socket
     
  3. grahamlthompson

    grahamlthompson
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    Lighting circuits are 5A, BS1363 ring main circuits are 30A with individual fusing in Plug Heads or in fused spur units with there own fuses. Fuses are useless for overload protection, they only work during short circuit conditions. A modern installation will have RCD (Residual Current Protection) which compares the Live and Neutral connections any difference results in an instantaneous disconnection of the power. Main problem with external supplies is mechanical protection with buried cables that normally use wire armoured cables. However a modern installation with a split load RCD protected system should be pretty safe. If it's an old fashioned fuse box do not consider it unless you give the circuit it's own RCD protection. You can buy kits to provide safe external supplies with a built in RCD. To the OP ignore this post, it's made by a poster who clearly has no knowledge and is peddling potentially lethal advice. Bathroom outlets have a isolating transformer built in that means even if you come into contact with the live terminal that no current can flow to earth so you are perfectly safe.
     
  4. xar

    xar

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    Thanks. I have an RCD box in the garage from which the wired external lights cable runs. Sounds like I will just get a professional out and run a new cable for me.
     
  5. ufo550

    ufo550
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    Final circuits come in different sizes & specifications, so dependant on the design and overcurrent protective device (OCPD), you could have a 5amp circuit, 6amp circuit, 16amp circuit etc etc. A BS1363 accessory is normally used with a circuit designed from 16amp (or 15amp) ocpd upwards. However, there's no regulation (as far as I'm aware) that prevents the use of a BS1363 socket on a lighting circuit. It's not good design, as dependant on the load, could cause unwanted tripping of the ocpd. I suspect there are hundreds of domestic properties with a socket outlets connected to a 1st floor lighting circuit, to provide power for a loft aerial booster etc. I make this point, for clarification, should others use this thread as guidance in the future.

    Fuses or ocpd are designed to provide overload protection as well as fault current protection, not sure if there is anything else? A BS1363 socket outlet, should not be installed within 3m from the edge of a bath or shower.

    To the OP, I'm not quite sure what you requirements are, but I would employ the services of a competent electrician. There are a few considerations for supplying a shed or outbuilding, outside of the equipotential zone (i.e. your house).
     
  6. xar

    xar

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    Thanks. Good info. I fully intend to use a pro, was just trying to figure out how feasible the idea is up front.
     
  7. ufo550

    ufo550
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    Not quite sure what you are trying to achieve?
     
  8. xar

    xar

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    Sorry. I have a driveway light on a fence where I am about to install a big shed. The light needs to go in order to get the shed flush, but I wanted to see if I could repurpose the connection to get a feed into the shed for both lights and mains. Consensus seems to be maybe for lights, prob not for 'mains'.
     
  9. ufo550

    ufo550
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    It is difficult to tell from your picture of your light, as to whether the cable is suitable or has a larger enough current carrying capacity (ccc), for your new intended use. Generally a steel armoured (swa) cable would be used, but consideration would also be needed for the intended load and possibly volt drop. There are also other considerations, dependant on the type of supply you have and of any extraneous pipework in your shed/garage. The best way to provide for an outside shed/garage supply, is from a non RCD supply in your house consumer unit (CU) with a swa cable, to a small RCD CU, or CU populated with RCBO's.

    I see you are from Scotland, you also have to be aware that a building warrant may be required, but I have no knowledge in that area.

    Best speak to a local competent electrician.
     
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  10. xar

    xar

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    Thanks. Will get someone local out to take a look.
     

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