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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. 

 

 

Parents
  • 0

    Try this for domestic premises.

    0.02 A per installed lamp.

    0.5A per installed socket (double or single). 

    32A for a kitchen +utility room.

    13A for water heater.

    32A Oven/hob

    Multiply total by 0.66 above. Then add.  

    32A for heat pump or preferably rating of heat pump.

    13A for 3kW EV charger.

    31A for 7.2kW EV charger.

    For an all electric house you are highly likely going to need load curtailment/load shedding.

     

    No doubt forum members will disagree with my back of an envelope calculation and want to tinker with my numbers but I would value your views. I think the above is more realistic than using the OSG method which for an all electric house is going to need a 3 phase supply. Why in the OSG does the number or rings the sockets are connected to matter?  Why does the load go up for the same number of sockets spread over multiple rings using the OSG calculation? 

    Lights touch paper and retires!

    JP

     

Reply
  • 0

    Try this for domestic premises.

    0.02 A per installed lamp.

    0.5A per installed socket (double or single). 

    32A for a kitchen +utility room.

    13A for water heater.

    32A Oven/hob

    Multiply total by 0.66 above. Then add.  

    32A for heat pump or preferably rating of heat pump.

    13A for 3kW EV charger.

    31A for 7.2kW EV charger.

    For an all electric house you are highly likely going to need load curtailment/load shedding.

     

    No doubt forum members will disagree with my back of an envelope calculation and want to tinker with my numbers but I would value your views. I think the above is more realistic than using the OSG method which for an all electric house is going to need a 3 phase supply. Why in the OSG does the number or rings the sockets are connected to matter?  Why does the load go up for the same number of sockets spread over multiple rings using the OSG calculation? 

    Lights touch paper and retires!

    JP

     

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