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100amp fuse overload

Discussion in 'Electrics UK' started by Sid1968, 28 Aug 2021.

  1. Sid1968

    Sid1968

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    Hi need some advise please
    Attended property to re wire 5 flats.
    The flats has electric only single phase 100amp fuse.

    Now the owner wants in each flats 5 of each
    8.5kw shower x 5
    5.5kw water heater x 5
    2 kw wall heaters x 10 plus
    3 kw hob x 5

    Thats over 100kw from each flat an thats not taking power and lighting circuit into account.
    That equates to well over 400kw from a 100amp fuse??

    Oh not to mention all flats will be submetered.

    Will a 3phase supply application suffice?
     
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  3. Guitarguy

    Guitarguy

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    I’d say a 7 way ryfield distribution unit supplied by 95mm cable would be what’s needed, a standard 3 phase supply would struggle, you’d have to share two of the phases not to mention overloading the neutral conductor
     
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  4. aptsys

    aptsys

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    You may need a separate supply for each flat, or suggest other forms of heating, but you don't just add up the rating of every appliance to work out the supply requirements.
     
  5. Sid1968

    Sid1968

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    Hi aptsys
    For future reference how to do u calculate the max load?
     
  6. flameport

    flameport

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    Double insanity.

    6x new supplies required.
    5 flats plus one for the common parts.

    If they want to reduce costs, say goodbye to instant electric showers and instant water heaters.
    One hot water cylinder per flat will reduce the total load significantly.
    However still needs individual new supplies for each flat.
     
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  7. oldbutnotdead

    oldbutnotdead

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    Landlord is being a shoddy so & so. If there's gas to the house he'd be far better off putting a gas boiler & a good sized cylinder in & using hot water meters to each flat. Cost for 5 new supplies could be very high....
     
  8. flameport

    flameport

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    It certainly will be.
    Landlord either pays for it, or sells the place if they really can't afford it.

    Regardless of the heating or fuel arrangements, 5 individual flats requires 5 individual supplies.
     
  9. JohnD

    JohnD

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    Apart from the landlord being barmy, he is assuming that he can find good-quality tenants willing to pay four or five times as much for energy, as they would if they lived in a home with gas heating.

    Good tenants will be looking for a better home no later than the day the first winter bill comes in.
     
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  11. AdrianUK

    AdrianUK

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    Care you explain how you think that's possible?
     
  12. wundaboy

    wundaboy

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    Not doubting you but I find this hard to believe, could you clarify?
    Is all this entirely correct? 5no 3kW hobs in one flat??

    1) What exactly is the size of the current incomer

    2) What is the total load (leaving aside diversity) per individual flat?

    3) What would be the total building load (leaving aside diversity)?

    If this is accurate, it sounds like each flat would need its own 100 amp 3 phase supply, and even then with diversity it would barely be sufficient. Sounds terrible!
     
    Last edited: 30 Aug 2021
  13. Sid1968

    Sid1968

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    Orginal post it states 5 flats off one 100amp supply so all appliances x 5
     
  14. winston1

    winston1

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    No it doesn’t. It states 5 flats with 5 of each item in each, that’s 25 of each item. Badly written but that is what it says.
     
  15. Sid1968

    Sid1968

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    D
    Sorry yes yur correct incorrect info

    Tot 5 flats each appliances in each flat
     
  16. wundaboy

    wundaboy

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    Reading between the lines I'd guess the owner won't want to pay to have this done properly, i.e. supply upgrade. I'd walk away from it.
     
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