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Wiring in my extension

Discussion in 'Electrics UK' started by delboybully, 7 Nov 2010.

  1. delboybully

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    I am having a 7m by 4m extension built. The builder is putting up the shell to make it water tight and i will be doing the rest

    I am going to do the wiring myself and then get an electrician to put in a new consumer unit and to also sign it off for building control.

    All the wiring in the extension is going to be on seperate fuses in the comsumer unit. I have rewired a previous house so i know some stuff

    we will be having 7 sockets inside with one external socket. How do i wire this in with a switch on the inside to turn it off? Do i use a fused switch?

    For lighting we are going to have downlighters, I have been recommended to have one every metre which means 18 downlights, (these are going to have 3 switchs to turn different sections on/off). Is this too many or not enough lights. There will also be 3 wall lights

    We are also going to have 2 ceiling fans (without lights) and 2 outside wall lights (the sensor types). Will all these lights/fans be ok on one fuse in the consumer unit or should i put them on 2 fuses

    In addition we are planning to have lights in the garden. I am going to put this on a seperate fuse. For this i have been told to use armoured cable. How deep does this have to be dug and how to i wire in a switch. Would a junction box be ok (wired in the same as the lights in the house) or does it have to be different?

    Thanks
     
  2. sparkwright

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    That's a lot of basic questions.
    I can't help wonder if it would be better if your electrician carried out this work. Or at least you asked him how it should be done, since he's going to be 'signing' this off.

    Do you intend to carry out just the first fix, or the second fix as well?

    Are you aware of rules for RCD protection?
     
  3. Taylortwocities

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    Some, but not too much - judging by the questions.

    Sparkwright has highlighted your first hurdle. An electrician won't/can't sign off your work as his own. You'll need to engage an electrician now and see how much you can do under his guidance.

    An experienced electrician can also give you guidance on the stringent requirements for energy saving.
    Especially downlights. How many of those 18 will be energy saving as defined in Building Regulations Part L1B?

    LABC are very hot on energy conservation (pun intended). Drilling 18 holes in your ceiling and removing all the nice insulation will not endear you to building control.
     
  4. riveralt

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    Competent Person scheme members are not allowed to sign other peoples work off!

    From what you said here and

    here you haven't got a clue!

    Way too many lights and the wrong type but what about the Building Regulations?

    Add up the wattage of all the lights and work it out - after diversity of course - you know how to do it because you have rewired a previous house - !!!! I hope I'm not living in it!!!!

    What type of 'armoured cable' are you going to use, plastic, copper, rubber?

    Ye Gods - STOP - you haven't got a clue - How on earth are you going to design these circuits, construct them and then test them to the satisfaction of building control.
     
  5. Stoday

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    How on earth are your 18 downlighters going to comply with the lighting requirements of Part L1B? You have to have at least 75% low energy.

    You should be installing fewer and larger cfl downlighters. 4 or 6 26W is all you need.

    Your electrician won't need to sign off your wiring. You should already have paid the Building Control fee; your installing some of the electrics won't increase the fee. You must tell the BC what you will be undertaking at the start though.
     
  6. ban-all-sheds

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    If you haven't already found one to do that you will not succeed.

    When you applied for Building Regulations approval what did you say would be the way you'd comply with Part P?


    Do you know how you would you go about deciding what cable and protective device to use for a circuit to supply a given load?

    Do you know which circuits can be ring finals and which cannot, and what the advantages and disadvantages of each are?

    Do you know what the two main lighting circuit topologies are, and what the advantages and disadvantages of each are?

    Do you know how to calculate maximum demand and how can diversity be used?

    Do you know what the 3 different types of domestic single-phase supplies provided in this country are, how to you recognise them, and what differences each make to the requirements for the rest of the installation, particularly any outdoor supplies?

    Do you know how to correctly identify all components and connections of a circuit by method of testing or otherwise? In doing so can you identify or recognise anything wrong or dangerous with the circuit?

    Do you know how the way in which you install cables affects how much current they can carry?

    Do you know what the rules are concerning cables concealed in walls, partitions and under floors?

    Do you know what the rules are for cables run outdoors, buried in the ground or overhead?

    Do you know how to join cables where this is necessary, and how this should be done / not be done and in what circumstances are different methods acceptable?

    Do you know how to identify extraneous conductive parts, and do you know the requirements for main and supplementary bonding of them?

    Do you know which circuits should be RCD protected?

    Do you know what tests you would carry out on the installation - what sequence you'd do them in and at what point you would energise the installation, and for each test do you know what is being measured, why it is important, how you would carry out the test, and with what equipment, and what sort of results you would expect to get if everything was OK?


    I thought you considered yourself competent to design electrical installations?


    Far too many.

    When you applied for Building Regulations approval what did you say would be the way you'd comply with Part L?


    I thought you considered yourself competent to design electrical installations?


    I thought you considered yourself competent to design electrical installations?


    I thought you considered yourself competent to design electrical installations?


    Click.
     
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  7. Taylortwocities

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    Sneaky but :LOL: :LOL: :LOL:
     
  8. echoes

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    I fell for that - I take my hat off to you b-a-s!! :LOL:
     
  9. ban-all-sheds

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    It was actually meant for the OP to click, as he'd said "thanks" :LOL:

    I wish I'd taken a screenshot of it while it still had holmslaw's name in the list :LOL:
     
  10. ban-all-sheds

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    Anyway.

    Would the person who gave my post a thumbs down care to say why?

    A reasoned explanation of why the questions I asked should not have been asked would be useful, i.e. showing why someone embarking on a job of that magnitude doesn't have to concern himself about what he tells LABC, doesn't have to know how to design circuits, how to get cable and MCB sizes right, how to ensure they are safely installed and so on.

    Such an explanation would be very useful to a large number of people, because it would show that there really is a way to successfully carry out major installation work without having to know how to do it.
     
  11. delboybully

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    I already have an electrician and am going to meet up with him. He is happy for me to put the cable runs in and to wire the sockets switches, lights etc but he says he will need to check them.

    The house i rewired was a simple job that consisted of 2 ring mains and 2 lighting circuits with pendant bulbs. I had my work tested by an electrician and it tested good. I did say i know some, i didnt say i knew loads- if i knew all i needed to know i wouldnt of posted!!!!!

    I asked the questions to help with knowledge of how to wire these extension in correctly

    It would of been nice if someone would of answered my questions, and if they needed a longer explanation then that would of been nice.

    Instead all i get from you all is, do you know this and that

    Thanks for the answer about energy saving requirements and the number of downlighters.

    I moderate on a forum and we keep it friendly. We dont flame and have a go at people who have done stuff wrong, we point them in the right direction. There is no such thing as a bad/stupid question, it is stupid not to ask a question. I feel that you have been less than polite whereas you could of steered me in the right direction in how to wire this job.

    As for taking the mickey out of me for saying thanks, then that is apalling, you should be ashamed of yourself ban-all-sheds!! How can you take the mickey out of someone being polite!!!!!!
     
  12. riveralt

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    This problem with the questions you were asking is that you were leaping to the installation stage before completing the design stage of the installation.

    The design stage determines how the installation stage will be conducted - so without that knowledge giving you answers to your questions would be frutiless.

    The electrician you are hiring should have sat down with you and agreed your electrical needs - he/she should then have designed the circuits taken into account all the mitigating factors.

    He should have answered all the questions you raised - there is no need to ask a DIY forum for answers when you are paying a professional to give them to you. It is by asking these types of questions that people on this forum may doubt that you are going to hire a professional and instead do it yourself.

    If the electrician is a member of a competent persons scheme then he cannot sign off other peoples work - it is not allowed. The best he could do would be to do a PIR on the installation at the end and state whether it complied with BS7671 - this, however, would not satisfy building control.
     
  13. delboybully

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    ok that makes sense. I havent met the electrian yet, i just wanted to have some knowledge before i meet him. I find when dealing with tradesmen that if you have some knowledge before hand is a good thing

    The electrician wants to see the designs from building control but the architect left these basic as i said i would sort them out with the electrician

    Lets start with the sockets. I have decided to put in 7 double sockets and a outside double socket which i want to be able to turn off from inside. The inside sockets will be on a ring main on a RCD consumer unit. This needs to be on a 32amp fuse but this is the electricains job!. What is the correct way to wire a switch for the outside socket. From my basic knowledge the choices would seem to be either a fused switch or a seperate mini fuse box (if you know what i mean).
     
  14. riveralt

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    As Part of the design stage for any job I do, I would talk to the client about their needs - and then create the circuit designs to meet their needs.

    You keep talking about ring final circuits - this may not be the right type of circuit for you needs. They electrician may decide that two radials would be better.

    He may decide that it is not possible, practical or legal to do what you want with the outside socket. Personally neither of your two suggestions are practical under the circumstances you describe - a 20amp dual pole switch would be more value.

    Once I had understood the clients needs I would design the circuits and complete wiring diagrams that I would work from or supervise the apprentice from.

    Stop trying to second guess how the electrician will design the circuit and be guided by what he says - he is the one who will be signing the job off and therefore he is the one who must be happy with circuit design.

    If you want the knowledge you desire look up the relevant sections on wiki.
     
  15. delboybully

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    I just assumed to put the sockets onto a ring, i thought this was the best way to go.

    I get your point though, i will speak to the electrician
     

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