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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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    vantech: 
     

    Why notify one and not the other? 

     

    The answer to this question is very simple.

    Whilst you may have a service head with a 100 A fuse holder, the fuse inside may well be 60 A or 80 A.

    There are a number of different reasons for this, but basically, for most properties, until an EV charger is required it's not really a problem.

    So, you notify the DNO if your MD (including EV) will exceed 60 A.

    The DNO will then be able to do whatever they need to do. In some cases, it's as simple as replace the fuse, in others it may involve upgrading the service cable, reinforcement of local network, etc.

    Occasionally there's a minor problem that some of the not-so-smart meters have to be protected by an 80 A fuse, and there's nothing the DNO can do about that. In those cases, the largest service fuse you will be given is 80 A.

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  • 0

    vantech: 
     

    Why notify one and not the other? 

     

    The answer to this question is very simple.

    Whilst you may have a service head with a 100 A fuse holder, the fuse inside may well be 60 A or 80 A.

    There are a number of different reasons for this, but basically, for most properties, until an EV charger is required it's not really a problem.

    So, you notify the DNO if your MD (including EV) will exceed 60 A.

    The DNO will then be able to do whatever they need to do. In some cases, it's as simple as replace the fuse, in others it may involve upgrading the service cable, reinforcement of local network, etc.

    Occasionally there's a minor problem that some of the not-so-smart meters have to be protected by an 80 A fuse, and there's nothing the DNO can do about that. In those cases, the largest service fuse you will be given is 80 A.

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