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Maximum demand calculation

vantech

Hi, 

I am trying to calculate a realistic and sensible maximum demand for a project:

Ring final (kitchen) - 32A (100%) 

Socket radial 1 - 20A 

Socket radial 2 - 20A 

Socket radial 3 - 20A 

Lighting 1 - 10A (2A) 

Lighting 2 - 10A 2A) 

EV charger (with load curtailment) - 40A 

Cooker - 15.3Kw = 10A + (30%) 16.95 = 27A. 

Can anyone advise what should be applied to the socket radials? These cover sockets on the ground and first floor of the property. I have allowed 100% of the kitchen ring, but what would be appropriate for the other radial socket circuits?

I am temped to treat them all as a single 32A ring circuit, and base this on the 40% value, equalling 12.8A.

Am I also safe to allow 40% for the kitchen ring, this allowing a maximum socket outlet value of 25.6A? 

Thanks. 

 

 

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  • 0

    mapj1: 
     

    The problem is with a 40A EV charger and a 65a cooker, there really  is not a lot of slack. I presume the place is heated by gas or oil, or at least not electricity, but the cooker is not gas so maybe not. If the sockets, and on the 100m2 rule of thumb, yes it could be seen as 40 odd amps worth of final circuits,  but of course that can be further diversified, (for a safe example 100 % of first 10 A +50% of  current demand in excess of 10A is the generic OSG way - that gives 10A+15A ) so more like 25A for all the socket circuits  into the full sum.

    Even so it will be hard to get it to add up to be much less than the full 100A, but we know that is not very realistic either, in the long term electricity bills see to the consumption being curtailed.

    Mike.

    Thanks. The cooker is 27A after diversity, so this is OK.

    The properly is gas but the plan is to add a hybrid heat pump for reduced gas consumption. 

    If i assume 25A for sockets this seems realistic.

Reply
  • 0

    mapj1: 
     

    The problem is with a 40A EV charger and a 65a cooker, there really  is not a lot of slack. I presume the place is heated by gas or oil, or at least not electricity, but the cooker is not gas so maybe not. If the sockets, and on the 100m2 rule of thumb, yes it could be seen as 40 odd amps worth of final circuits,  but of course that can be further diversified, (for a safe example 100 % of first 10 A +50% of  current demand in excess of 10A is the generic OSG way - that gives 10A+15A ) so more like 25A for all the socket circuits  into the full sum.

    Even so it will be hard to get it to add up to be much less than the full 100A, but we know that is not very realistic either, in the long term electricity bills see to the consumption being curtailed.

    Mike.

    Thanks. The cooker is 27A after diversity, so this is OK.

    The properly is gas but the plan is to add a hybrid heat pump for reduced gas consumption. 

    If i assume 25A for sockets this seems realistic.

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