3 phase to single phase (sub-main)

Discussion in 'Electricians' Talk' started by Emre, Sep 26, 2019.

  1. Emre

    Emre New Member

    I have a greenhouse and received a quote from the Scottish hydro for a new electric connection.

    Here is the details:

    Connections: 1 Com/Ind three phase 50kVa connection for a greenhouse, no abnormal loads.

    The connection will be three-phase, 400/230 Volts, and alternating current at 50 Hz, with a maximum capacity of 50kVA. Where your connection involves multiple phases you will need to balance the electrical load evenly across the phases to avoid overloading.

    My question is:
    I am planning to build a shed and keep the main meter there so that I can accept this offer and get connected quickly.

    Greenhouse is about 140 meters away. Just now I don't need a 3 phase electric in the greenhouse. I am planning to have lots of grow lights.
    Can I sub-main a single phase from the main meter to the greenhouse? I am guessing I would use max. 20kva in the greenhouse.

    Also what does 1 Com/Ind three phase mean?
  2. Commercial/industrial.
    Emre likes this.
  3. HappyHacker

    HappyHacker Active Member

    They are expecting you to balance the load across the phases so you should spilt your green house lights in to three sets each set on a different phase.
  4. Peterdevon

    Peterdevon Active Member

    It will be cheaper to run all three phases as the cable size will be considerably smaller, you will probably have to TT it so that saves a core.
  5. Emre

    Emre New Member

    What do you think the size and cost of the cable will be if I go for the 3 phase?
    The length is around 140 meters?
  6. Peterdevon

    Peterdevon Active Member

  7. sinewave

    sinewave Screwfix Select

    I'd have your DNO supply located nearest the highest load.

    If this is going to be the greenhouse then build a DP Cupboard just outside and have the new supply installed here.
  8. sparky Si-Fi

    sparky Si-Fi Screwfix Select

    What you growing in that lot? ;) standalone meter cupboard so they can bring in cabling, Distro board inside for final circuits

    Hello Sine me owd cable joint, whats occurin'?
  9. sinewave

    sinewave Screwfix Select

    Alright Si-Fi!

    Thought I'd drop in, been a while lol! :)

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