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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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    Chris Pearson: 
     

    BOD makes a good point. Another high consumption load would be a swimming pool heater. Daughter's first quarterly leccy bill was £900, but that's a nice steady load.

    When I discussed load with SSE, they seemed to be concerned about large motors - you don't want the neighbours' lights dimming - but 3-phase seemed to be much more acceptable. I can draw 69 kW (or more briefly!) but the agreed ADMD is only 30 kW. If it ever got that high for a significant period I would wince. ?

    What if the maximum demand is already above 60A and the consumer wants to add an EV charger? 

    The rule is that you have to get permission from the DNO if the “new” maximum demand is >60A, but what if the current (before EV charger is installed) maximum demand is already above 60A? 

    An energy management solution in the EV would stop the charger if it measures a load over 60A, so adding an EV charger would have little to no impact on the current, household maximum demand. 

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  • 0

    Chris Pearson: 
     

    BOD makes a good point. Another high consumption load would be a swimming pool heater. Daughter's first quarterly leccy bill was £900, but that's a nice steady load.

    When I discussed load with SSE, they seemed to be concerned about large motors - you don't want the neighbours' lights dimming - but 3-phase seemed to be much more acceptable. I can draw 69 kW (or more briefly!) but the agreed ADMD is only 30 kW. If it ever got that high for a significant period I would wince. ?

    What if the maximum demand is already above 60A and the consumer wants to add an EV charger? 

    The rule is that you have to get permission from the DNO if the “new” maximum demand is >60A, but what if the current (before EV charger is installed) maximum demand is already above 60A? 

    An energy management solution in the EV would stop the charger if it measures a load over 60A, so adding an EV charger would have little to no impact on the current, household maximum demand. 

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