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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: 
     

    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.

     

    is the 2A the real max load on the lights? - if it is LED or even CFL, you get a lot of lighting for an average current of an amp. 

    Mike

    The house is 150m2. That would be 48A for socket outlets as a maximum demand calculation - that’s 11kw of power from socket outlets, seems a bit high to me? 

    The loading on the lighting circuits would be around 1amp. The customer wants to add an air source heat pump onto the 100A supply and I need to calculate the theoretical maximum. The heat pump draws a maximum of 28A when less than 5 degrees outside. 

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  • 0

    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.

     

    is the 2A the real max load on the lights? - if it is LED or even CFL, you get a lot of lighting for an average current of an amp. 

    Mike

    The house is 150m2. That would be 48A for socket outlets as a maximum demand calculation - that’s 11kw of power from socket outlets, seems a bit high to me? 

    The loading on the lighting circuits would be around 1amp. The customer wants to add an air source heat pump onto the 100A supply and I need to calculate the theoretical maximum. The heat pump draws a maximum of 28A when less than 5 degrees outside. 

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