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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 :)
  • 0
    wallywombat:

     That works out at about 3.5A per house.

     


    In theory ... but most cars won't charge at less than about 10 A, otherwise it kills the batteries.


  • 0
    Customers expectation will be that they can get home at tea time and leave the car on a quick charge whilst they shower in a toasty warm house and eat a meal, as well as having put a load of washing in, along with another load in the dryer before going out in the car again.


    All achievable with an endless supply of electricity.
  • 0
    wallywombat:

    If you make the rough assumptions that the total mileage of each household is 10,000 miles per year and that EVs do about 5 miles per kWh, then the existing domestic infrastructure can just about cope as long as cars are given a slow 7 hour-ish charge each night when the local network would otherwise be mostly unused. That works out at about 3.5A per house.


    What about diversity? If everybody charges slowly at the same time, there is none; but if cars are charged quickly quite a lot of diversity could be applied. Granted we might all try to travel at the same time, but that doesn't mean that we would all plug in at the same time.


    I don't know how far the average car commute is, but 20 miles is more than enough for me. That's 10 kWh (for both ways) or about an hour and a half on a 7 kW EVCP.


  • 0
    Another point worthy considering is that the voltage drop on the DNO network is going to be a problem at the remote end. Here at least assuming  the TX is set at 250 volts we get around 18 volts drop at peak times and thats with normal load not an EV in sight
  • 0
    A related issue today in the dorset Echo if you can google it do t know how to post a link
  • 0
    These new petrol stations are actually a nuisance, even if they have pay at pump you end up waiting to use the pumps because cars have been left on them whilst their drivers are getting a Subway or Greggs sandwich and a Costa coffee.


    I actually prefer and choose to use the filling stations with less “facilities”and food outlets as you can be five miles or more closer to home without the delays.
  • Former Community Member
    0 Former Community Member
    I think that the next big shock will be the level of tax for electric vehicles once they become a significant proportion of vehicles. Interesting times ahead!


    Well they did it in the late 80's early 90's when petrol was £1.75 a gallon but diesel was only £1.50 a gallon. As the revenue fell due to less petrol being sold, the price of diesel increased to be where we ae today with diesel being dearer than petrol. The same happened with LPG and as David indicated, the loss of fuel revenue will no doubt come from the alternative source/use of energy...........Unless St Greta can make up the lost revenue.................


    Regards


    BOD
  • Former Community Member
    0 Former Community Member
    And no doubt the price of electricity will sky rocket
  • 0
    Red dye in domestic electric might make lighting a nice rosy colour.
  • 0
    Thanks for the input, although we did go off at a slight tangent ?

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