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Multiple 3 phase supplies

Sparky Dan

I’ve got some works to do at a hotel/restaurant. The hotel is on a 3 phase supply and the restaurant on a separate 3 phase supply.
They’ve asked me to wire in a large induction hob in the restaurant kitchen but unfortunately the load is already at capacity in the restaurants main board so was going to come off the hotel board to a new 3 phase board in the restaurant kitchen and to the induction hob.

I can’t see this being an issue if everything’s labelled correctly etc but would I have to connect the two METS together?

Thanks Dan

Parents
  • 0

    Apart from the earthing considerations there is also the question of the lack of a single means of isolation.  Whilst this isnt a specific 7671 requirement it could be an issue in this sort of environment.  Labelling and notices will be OK for a situation where people have the time and inclination to read and understand them but in an emergency such as fire or electric shock it needs to be instantly clear how to turn off the power in my view.  Tin hat on....

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  • 0

    Apart from the earthing considerations there is also the question of the lack of a single means of isolation.  Whilst this isnt a specific 7671 requirement it could be an issue in this sort of environment.  Labelling and notices will be OK for a situation where people have the time and inclination to read and understand them but in an emergency such as fire or electric shock it needs to be instantly clear how to turn off the power in my view.  Tin hat on....

Children
  • 0 in reply to statter

    This may be a situation where the 'my oven  is on fire' sort of isolation needs to operate appliances on both supplies , or be to isolators side by side so it is obvious on inspection how to turn off which item- the argument  'no local isolation needed it can be switched at the MCB' looks weak if it is in another building or unclear which board.

    Mike

  • 0 in reply to statter

    Thanks for replying there will be an isolator, correct cable used, MCBs etc  

    I’ve spoken to the DNO and have a site visit soon to discuss.

  • 0 in reply to Sparky Dan

    sounds like you have it all under control - especially the DNO visit part - a good chance to pin them down on what they want to see.
    Mike

  • 0 in reply to mapj1

    I agree Mike.  Arguably reg 12 of the Electricity at Work Regulations requires a single point of isolation/disconnection in this sort of installation given the likley knowledge and experience of those needing to cut the supply in event of an incident. 

    Historically a number of DNOs refused to provide multiple supplies because of this and preceeding regulations but I am not sure what the policy(ies) is/(are) now. 

    I have always been surprised that the need for considering a single point of isolation doesnt feature more in the regulations.

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