new consumer unit to outbuilding

Discussion in 'Electricians' Talk' started by switchoff, Oct 24, 2003.

  1. switchoff

    switchoff New Member

    I am providing power to a small ouitbuilding 6 metres from the existing house and existing consumer unit. I am intending to provide a sub circuit via a new 2way consumer unit. The supply will come from a spare mcb in the existing unit. As i understand it the wiring regs require the new con unit to be seperately earthed. The earth wire from the existing consumer unit will not therefore be connected to the new consumer unit but a seperate earth cable and earth rod will be used. The new con unit is rcd protected. Is this the correct/best way to provide this power to the outbuilding? If the supply cable earth core is connected to the earth in the old consumer unit do I need to terminate this in any specific way wherer it reaches the new con unit as it will not be connected?
  2. SteveC

    SteveC New Member

    Just connect the earth from existing supply into the earth bar on the new consumer unit as well as the new earth - it wont hurt to have 2. Also make sure your mcb in your main consumer unit is rated correctly for what you're planning to use in the outbuilding.
  3. Sparkyman

    Sparkyman New Member

    If you have an earth block at your existing main board then take your earth from there ...

    Is the supply to the outbuilding SWA (steel wire armoured cable, if so then you will possibly have to terminate into a junction box at the existing board and come out and into the MCB with a bit of T&Earth cable depending on the type of consumer unit you have
  4. switchoff

    switchoff New Member

    Using pvc sheathed in conduit. Will taking earth from existing con unit meet wiring regs?

    Thanks for your help
  5. Sparkyman

    Sparkyman New Member

    Another point to consider before you take the earth from the main earth connection at your board is whether you have a PME installation (there should be a yellow sticker stating this if you have)and if so then use the earth rod set up only as you could end up with a difference in potential between the 2-earths which is not a good idea
  6. Sparkyman

    Sparkyman New Member

    If a standard installation I personally would take my outbuilding earth from the main earth connection in the house but I would run a seperate 6mm earth cable in the conduit along with the PVC T&E supply cable
  7. Brightspark

    Brightspark New Member

    Good point sparkyman about the PME earthing arrangement and an often overlooked one by many a spark.

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