Socket in CU cupboard

Discussion in 'Electricians' Talk' started by Shaun G, Sep 22, 2021.

  1. Shaun G

    Shaun G Member

    I am wanting to put a socket in the same cupboard as my CU. I would like a socket in there to charge my dyson hoover as i dont really have another place for the hoover to go. I am reading up about conecting sockets directly to the CU off an MCB. Is this do-able? Seems like theres some mixed oppinions about this with regs and what can be done by DIY as supposed to a PRO.
  2. ElecCEng

    ElecCEng Screwfix Select

    You are installing a new circuit so it’s notifiable. Even if you’re competent and have the required test equipment, then the LABC fees are probably going to be prohibitive.

    An alternative would be to add a 5A fused spur to the lighting circuit that serves the CU location.
  3. Bob Rathbone

    Bob Rathbone Screwfix Select

    Shaun, you may spur off or add to an existing socket circuit by connecting directly to the appropriate breaker in the CCU. This is not counted as adding a circuit and does not need LABC approval or any of the other 'Guilds of Compliance' certification. Do not be tempted to install a new breaker for your socket, that would be counted as a new circuit.
    seneca, Shaun G and ElecCEng like this.
  4. Shaun G

    Shaun G Member

    This is what i was intended on doing, basically adding an fcu then onto the double socket to the MCB in the CU to sockets downstairs. I just wondered if it was ok to do this myself. Not adding any new circuits or anything
  5. Bob Rathbone

    Bob Rathbone Screwfix Select

    To keep to the Regulations (BS7671), you must be competent and be able to test the installation before use. However, the Regulations (BS7671) are not enforceable in Law, it is only when the requirements of BS 7871 are supported by the Buildings Regulations that statute law become applicable.
  6. Coloumb

    Coloumb Screwfix Select

    ElecCEng likes this.
  7. Shaun G

    Shaun G Member

    would a simple fcu spur be adequate enough
  8. ElecCEng

    ElecCEng Screwfix Select

    Taken from the loop of a lighting cct yes.

    Extending a radial socket circuit, not required.

    Extending a ring final socket circuit, yes ideally, but you need to make the FCU part of the ring.

    If you are planning on adding to a breaker which supplies a socket circuit, a FCU would only be required if it was >16A breaker. If you are doing this, turn off all power by opening all breakers then RCDs, then turn off the main switch. Be very careful that all wires are clamped in the correct part of the breaker, ideally to the manufacturer’s recommended torque. “Loose wires cause fires”

    Hope that’s clear!

    Shaun G likes this.
  9. adgjl

    adgjl Member

    Why? Electrically it is no different to an unfused spur from a socket on a ring.
    Shaun G likes this.
  10. Shaun G

    Shaun G Member

    This is what i thought
  11. Coloumb

    Coloumb Screwfix Select

    I think the confusion is the way the op posted.

    If you add a new breaker in the CU then its a new ctt = notifiable, if you add a single socket spur at the origin of the ctt, (ie the ring final mcb) then technically its a spur as it's an addition to an existing ctt.
    Shaun G likes this.
  12. Shaun G

    Shaun G Member

    Ok so i will not be adding a new mcb just to be clear.

    All i want to do is add a double socket in the same cupboard as the consumer unit. I have no space for one in my kitchen now its all plastered and tiled so in this cupboard is the best place for what i need the socket for. I want the easiest route for wiring which will be directly to the consumer unit as its less than 3 foot away from were i need the socket. I just wanted to know what the easiest way was to go about this is, if its possible and possible by law. If so is it possible for me to do this work (diy) or do i need a pro? And if anybody had any info of how it shall be done. Cheers hope this clears a few things up.
  13. ElecCEng

    ElecCEng Screwfix Select

    What are the options in your CU? Sockets should normally be on a 16 or 32A.

  14. Shaun G

    Shaun G Member

    All my sockets seem to be on 32A
  15. DIYDave.

    DIYDave. Screwfix Select

    OK, I’m strictly diy but this is how would add/have added an additional socket in same position -

    Main switch to CU off

    Identify MCB that supplies sockets on same floor as this additional socket your planning

    Likely to be 2 wires terminated at MCB - either 2 reds or 2 browns

    Neatly feed a length of 2.5mm T&E into CU at convenient position and strip away enough outer sheath to allow each core to be terminated - outer sheath must be intact as cable enters the CU

    Connect live to above MCB. Ensure all three cores sit in a row inside the clamp of MCB and are not twisted together or overlapped and no copper on show

    Make N & E connections - obviously sleeving the bare E core

    Now give each of these cores a tug and visual inspection and check again all firmly clamped, good contact onto copper - not outer insulation, neatly routed inside CU, etc

    Decide on new socket position inside cupboard and plan cable run. Either run cable inside trunking/conduit or clip to surfaces. If cable exposed, ensure its out the way and unlikely to become damaged by simply using the cupboard / getting things in and out of space / feet / shelving / etc (this also goes for socket position)

    Fit socket to planned position and connect up the cable, check all connections, as above (As you’ve only got 1 core going to each terminal in socket, strip off more insulation and double over each core to give more copper for the screw to bite onto - also stops a single piece of copper shifting sideways inside the terminal as screw is tightened)

    Power back on and that’s it
    Enjoy your new socket :)

    I’m assuming you have a straightforward CU fitted, all MCBs in 1 row - not a split load board or anything ‘fancy’ ! ?
    Starslikedust and Shaun G like this.
  16. Tony Goddard

    Tony Goddard Screwfix Select

    Spot on, good description of the task, two points to reinforce, 1/. turn off the whole board before working and remember the main tails are still live. 2/. ensure the wires (all of them, not just the new one) are tightly clamped in the MCB.
    DIYDave. and Shaun G like this.
  17. Shaun G

    Shaun G Member

    How would you go about terminating the E & N? In the same terminals and as the mcb is connected to or its own terminal?
  18. Tony Goddard

    Tony Goddard Screwfix Select

    Yes, in the same terminals on the busbars as the existing N & E for that circuit is in - in theory the earths and neutrals are supposed to be in the same order as the MCBs - in practice it sometimes gets muddled up, but we aim for perfection!!
    Shaun G likes this.
  19. ElecCEng

    ElecCEng Screwfix Select

    Also the sort of thing the AM2 gods love to needlessly fail apprentices for… :rolleyes:

  20. MGW

    MGW Screwfix Select

    The operative word is "New" so connect a socket to the ring final and not a new circuit, and it can be connected in the consumer unit, at least BS7671:2008 shows it as an option not got 2018, so once used once then you can transfer to spare MCB/RCBO as now not a "new" circuit, which is clearly crazy.

    The big question is who would know? And the case law is unlikely to exist, for it to come to court in the main some one must die. So we have cases like Emma Shaw which show a semi-skilled worker (electricians mate) can't be used to plug in a tester and record the reading. But until Emma Shaw's death I know I used electricians mates to plug in a machine and take readings.

    A consumer unit is a type tested distribution unit designed to be in the control of an ordinary person, if it requires a skilled person to work with a consumer unit, then what is the point of the type testing?

    Some times you look at laws and wonder why worded that way? Why even call the distribution unit a consumer unit in the law? Would make sense to call it a distribution unit then it would cover old and new units, before and after type testing came in, maybe it was called a consumer unit so we could get around the law and fit some thing not recommended by manufacturer which removes the type testing so makes it a distribution unit only?

    So if you connect into the CU and you kill yourself you will likely be quoted like Emma Shaw as we talk about the laws, as you will likely make case law. HSE says we should always isolate elsewhere, in my home I have an isolator before the CU so I can isolate elsewhere, but many homes are lacking this isolator so following HSE rules you should don all the safety clothing, turn off isolator on CU then draw the DNO fuse, and clearly that would break the DNO seal, so again it needs a court case to say if the DNO have not supplied an isolator can you draw the fuse?

    Personally I do not want to have to justify my actions in a court of law, be it right or wrong I don't want to have to argue the case. Neither do I want to be accused of killing anyone, even if I can prove not my fault, I don't what to have to stand up in court.

    Ionisation is the biggest fear of the electrician, under some conditions the atmosphere can become conductive, this causes a big bang, and can throw people across a room, lucky not very common, but all it takes is one spark to start it, so forget about the law, think of your own safety, don't remove the lid of any electric box which has power in it, so best option is to get a scheme member to do the work, 230 volt is potentially dangerous, leave it to people trained to know how to reduce risk to a minimum.

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