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Generator powered installation within a house with mains supply?

I have been asked to advise on if it is possible to use a generator to power a small temporary installation within a building with mains supply. The temporary installation would be isolated from the mains supply via use of safe distance and physical barriers. There would be no possibility of equipment being plugged into both power supplies. Does anyone have any advice on this?

  • Yes, but how easy depends on the size of the install. More details please.

  • certainly possible and quite common for builders tools during refurbishment for example, or  if the temporary installation needs far more power than the mains can supply - like event catering or even theatrical lighting for a show on a remote site.

    The two cases are very different, and in either case some knowledge of the load, the location and power of the genset, earthing arrangements etc would help give more relevant advice. Then there are cable routes, voltage drops trip hazards, refueling procedures....

    All possible.

    Mike.

  • The temporary installation would consist of a 32A single phase power outlet and approximately 8x 16A sockets. A total power consumption of around 8kW. This would be within a large hanger that is partitioned off with any local mains supply sockets blanked off. Cannot find anything in the Wiring Regulations that stipulates you cannot do so?

  • no real need to blank off the house sockets so long as you can ensure the earth potentials are tied together, no worse than single phase sockets fed from more than one phase side by side then, perfectly acceptable since the mid 1960s -  I presume the genset is diesel and outside, so will need earthing to something solid anyway.
    Mike

  • Temporary installation would be insulated through distribution equipment to the diesel generator earthed outside the building yes.

  • Earthing (or bonding at least) would likely need to be common for the building and generator. (unless the two installations, including all extraneous-conductive-parts, were out of reach of each other, including any portable equipment)

        - Andy.

  • Earth outside but please also bond temp supply to building earth, either at MET or via suitable shared metalwork (girders, plumbing etc.)
    M

  • Begs the question - why not use the mains supply for the temporary installation?. 

    Jaymack

  • usually when the local supply is going to be off for a bit, perhaps being moved during building work, or inadequate capacity. He has not said which.
    M.

  • Earthing (or bonding at least) would likely need to be common for the building and generator. (unless the two installations, including all extraneous-conductive-parts, were out of reach of each other, including any portable equipment)

    If ADS is used, BS 7671 actually requires this. See Regulation 411.3.1.1