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EV max demand vs. Normal high load reporting to DNO

vantech

Hi, 

A question that’s bugging me, if anyone can comment. 

We are required to notify the DNO if the maximum demand exceeds 60amps, when installing an EV charger (unless there is load management built into the EV charger). 

What I am trying to understand is how a load in excess of 60amp caused by an EV charger differs from normal, high power loads within a property. 

If we have for example: 

An induction hob/oven on a 32A circuit 

Spa/Hot tub on a 32A circuit 

Heater on a 13A plug top 

Our demand here would be 77A (plus or minus pending how the hob/tub/heater is switching its outputs - either way, it would be above 60amp give or take. 

Why doesn’t this need notifying? 

If a house with minimal loading reaches 28A and the EV charger reaches 32A, the total demand on the network is still only 60A, much less than the 77A taken in the first scenario. 

Why notify one and not the other? 

A consumer should be able to draw up to the maximum rating of the fuse surely, but is there a “limit“ when the DNO needs to be told? 

Thanks. 

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    perspicacious: 
     

    Why notify one and not the other?

    Simply because the sustained “domestic load” isn't 15 kW, roughly £3 an hour as this would equate to a weekly bill of £500…………………………………….. An interesting example would be to take your quarterly kWh usage and calculate your average load. It might be typically 0.6 kW.

    Yet, do the same for a 7 kW EV load charging a 50 to 90 kWh EV battery three times a week and see why the DNO have concerns……………………….

    Regards

    BOD

    Makes sense. 

    So it’s the continuous use that’s the issue and not the actual peak.

    For instance, the install could peak to 60-70A for a period of time, whist someone is cooking + showering + heating, but this would taper off as things are shut down. 

    An EV charger is different, if six houses all had EV chargers running it’s a continuous load for long periods of time. 

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  • 0

    perspicacious: 
     

    Why notify one and not the other?

    Simply because the sustained “domestic load” isn't 15 kW, roughly £3 an hour as this would equate to a weekly bill of £500…………………………………….. An interesting example would be to take your quarterly kWh usage and calculate your average load. It might be typically 0.6 kW.

    Yet, do the same for a 7 kW EV load charging a 50 to 90 kWh EV battery three times a week and see why the DNO have concerns……………………….

    Regards

    BOD

    Makes sense. 

    So it’s the continuous use that’s the issue and not the actual peak.

    For instance, the install could peak to 60-70A for a period of time, whist someone is cooking + showering + heating, but this would taper off as things are shut down. 

    An EV charger is different, if six houses all had EV chargers running it’s a continuous load for long periods of time. 

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