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Maximum Demand / ENA / EV Help!

D4G
Hello all,


This evenings issue relates to an EV charger install.

The supply cut out is labelled 60/80 amp so I called the DNO and asked if this could be uprated to 100 amp.

They have sent me the ENA EV application form which asks for the Maximum Demand including the new equipment.

The problem I have is the existing circuits are:


32A - 7.2 kW shower 

40A - 8.2 kW shower

32A - Ring main

32A - 7.9 kw cooker

6A - lighting

6A - lighting

6A - security


Additional 32A for EV charger


So even with diversity I'm way over 100A, obviously in reality the diversity calculations are not appropriate as the client has never blown the cut out.

The smaller shower is not currently in use although they want to replace it for another one, I have told them this may not be possible.

The EV charger will have load management but I still need to put a figure on the ENA form....


Help appriciated :)
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    John Peckham:

    D4G


    You have to notify the ENA if your MD will go over 50A and they will notify the DNO.


    The best way to verify your MD is not by calculation but power logging the supply over a week. either using a power logger or a recording clamp meter that will last a week on the battery and will not automaticay turn off after a set period.


    Having established your MD add the EV demand and you have your new MD. With a 60A main fuse you are going to need load curtailment or s supply upgrade.


    60a is the figure, if below 60 then you can notify DNO after installation but if above 60 then you should notify before installation. 


    Logging the consumption is the answer but not so practical and I doubt a common practice being as customers want answers today! 


    I believe the norm is to request a 100a upgrade before EVSE installation, this is what I asked for when was presented with the ENA form. 


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  • 0
    John Peckham:

    D4G


    You have to notify the ENA if your MD will go over 50A and they will notify the DNO.


    The best way to verify your MD is not by calculation but power logging the supply over a week. either using a power logger or a recording clamp meter that will last a week on the battery and will not automaticay turn off after a set period.


    Having established your MD add the EV demand and you have your new MD. With a 60A main fuse you are going to need load curtailment or s supply upgrade.


    60a is the figure, if below 60 then you can notify DNO after installation but if above 60 then you should notify before installation. 


    Logging the consumption is the answer but not so practical and I doubt a common practice being as customers want answers today! 


    I believe the norm is to request a 100a upgrade before EVSE installation, this is what I asked for when was presented with the ENA form. 


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