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Maximum demand calculation

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. 

 

 

Parents
  • mapj1: 
    It may help to consider how much floor area are you serving - there is a limit to the number of kW anyone will dissipate in a small space for very long without overheating and turning things off - the 32A per 100m2 rule may be more realistic for domestic regardless of how many circuits  it is divided over.

    That depends very much upon the insulation, but the likes of Grand Designs suggest that a few kW can be sufficient.

    Let's not forget that the heat emitted by a cooker stays in the house one way or another, be it during cooking, whilst the food is on a plate, or even after being eaten. Same for your tea and coffee, and even when using a food mixer (a Kenwood as we used to say).

    Of course if you don't pay for your heating directly, it is easiest to regulate the temperature by opening windows. ?

Reply
  • mapj1: 
    It may help to consider how much floor area are you serving - there is a limit to the number of kW anyone will dissipate in a small space for very long without overheating and turning things off - the 32A per 100m2 rule may be more realistic for domestic regardless of how many circuits  it is divided over.

    That depends very much upon the insulation, but the likes of Grand Designs suggest that a few kW can be sufficient.

    Let's not forget that the heat emitted by a cooker stays in the house one way or another, be it during cooking, whilst the food is on a plate, or even after being eaten. Same for your tea and coffee, and even when using a food mixer (a Kenwood as we used to say).

    Of course if you don't pay for your heating directly, it is easiest to regulate the temperature by opening windows. ?

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