Consumer Unit Sizing and Cost - Help Please!

Discussion in 'Electricians' Talk' started by Baron88, Apr 15, 2020.

  1. Baron88

    Baron88 New Member

    Hello All,


    Need some help on consumer units. I’m renovating a house and it needs a rewire and a new consumer unit and I need advice of the correct sizing, understanding of costs and good brands. For reference its 3 bed semi-detached house in Coventry and below are a list of circuits that I think I may need.

    1. Upstairs ring
    2. Downstairs ring
    3. Upstairs lighting
    4. Downstairs lighting
    5. Upstairs bathroom (Fan, lights etc.)
    6. Downstairs shower room (Power shower, fan, lights etc.)
    7. Kitchen
    8. Outdoor garden socket
    9. Front door lights and security camera (ring or nest)
    10. Back door lights (flood)

    Many thanks in advance.
     
  2. Hfs

    Hfs Screwfix Select

    Why isn’t your electrician giving the guidance on what to buy or even supplying the gear?
     
  3. Baron88

    Baron88 New Member


    Hello. This is true, I'm getting my ducks in a row (so to speak) before having that conversation. Thus getting an idea of what I actually need and what its roughly going to cost so I dont get ripped off.
     
  4. sparky steve

    sparky steve Screwfix Select

    Depends on the electrician you employ, as to design of installation, example he may prefer to install radial circuits in preference to ring final etc, usually you would obtain three quotes and then decide.
    Regards
     
    Hfs likes this.
  5. Baron88

    Baron88 New Member


    Hi Steve, thanks for the info. As i'm not a sparky, what the pros and cons or a radial vs ring? It was my understanding that ring circuit was the defaut for UK houses, was that assumption wrong?
     
  6. Bazza

    Bazza Screwfix Select

     
  7. Hfs

    Hfs Screwfix Select

    Hager for the board, click or Schneider lisse for accessories, monsoon for fans, Collingwood for downlights and aico for smokes/heats. As a rough rule of thumb add up every point including sockets, switches,2 ways, pendants, downlights, fans, fan isolators, fan grills, smokes, heats, bonding to gas and water, appliance power, thermostat wiring, power to cameras, power for Aerial booster, tv points, bt points, Ethernet points, board, cookers, induction hob, outside socket, outside lighting and anything else you can think of. Times this figure by £60 and this will give you a rough estimate of where you should be on price. Obviously Then add on anything that you go above and beyond with such as if you went for a full RCBO board, USB sockets, chrome sockets etc.

    If it’s lived in then add on half the cost again .

    Get the electrician to supply the gear so he then provides a warranty if anything goes wrong. You will not save anything by trying to supply the gear.
     
  8. Comlec

    Comlec Screwfix Select

    @baron Stop wasting your time on the consumer unit and spend some time on this list.

    Read this guidance from Electrical Safety First then

    Draw a plan of your house (all floors) and external areas if required
    On the plan mark the following
    • position of incoming supply
    • position of the new consumer unit
    • position and power rating of all kitchen appliances (including ovens, fridge freezers)
    • position and power rating of shower
    • any dedicated heating (immersions, water heaters, under floor heating)
    • all electrical outlets (with intended purpose where known)
    • all lighting points and controls
    • all smoke,heat and CO detectors
    optionally
    • add all AV points
    • alarms, cameras and any other gizmos
    As all circuits need be protected by an RCD, your next action is to decide whether you want your circuits protected by its own RCD or you are prepared to have circuits share an RCD. The best, but more expensive option, is to opt for an all RCBO board but you could opt for the inferior dual RCD board.

    You also need to decide whether you wish to fit an SPD (Surge Protection Device) to the new consumer unit. All you need do ask for the electrician to quote for this. Then if you believe the cost of protection is a benefit then fit it.

    Spend some time drafting your specification so it an accurate description of what you want. You can then invite local contractors to quote based on your specification.

    Get quotes from three contractors.
    Ask for the quote to include a base price for standard white fittings from a manufacturer you specify (eg Schneider, MK, Contactum etc) standard pendant drops, an all RCBO board including the cost of the SPD.

    This will allow you to accurately compare quotes. You can then have the quotes amended if you select more expensive fittings or agree to have components omitted.
     
  9. Bazza

    Bazza Screwfix Select

    As for radial v ring. It’s a matter of circuit design. Socket circuits have traditionally been ring final for several decades, but we are one of the few countries who do this.

    Most of the World use radial circuits for socket circuits. It’s a matter of cable routes and types, loading and other factors that your competent and registered electrician will consider when he does the circuit and cable calculations. That’s his or her value added, and why electricians undergo training and competence testing.
     
    sparky steve likes this.
  10. SidDIYer

    SidDIYer Member

    Don't forget to ask for a charge point for your new electric car :)
     

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