There seems to be a standard installation developing for domestic EV charge points where it is 6mm2 no matter what. I checked one installation which will have around 9v dropped on a 7Kw charger. Ok, I acknowledge that the full load current won’t be pulled at all times but it can be assumed that there will be long periods when it will. Multiply that by an ever increasing demand across the nation and we can expect to see considerable energy wastage. Perhaps, we should be setting tighter limits than 5%.
The payback of a larger cable to an EV charger cant be calculated exactly because we dont know the hours of use or future energy prices.
A payback time of some years is in my view acceptable, and may compare well with say double glazing.
If the car needs replacement before payback is achieved, that is not relevant IMO, the cable can be used for the new car.
Converting EXISTING services to three phase could be costly, and I do not propose this unless required. I do however suggest that most NEW services should be three phase. Three single phase consumer units should serve in most cases.
L1 cooker, EV charger, and kitchen ring final.
L2 Electric shower, water heater, second EV charger.
L3 Everything else, including any second electric shower.
Or some similar arrangement.
Otherwise, I foresee a lot of cooked 60 amp single phase services. AFAIK there exists an EV charger that monitors (via a current transformer attached to the meter tail) the total load on an installation. If the load would otherwise exceed 60 amps, then the EV charger slows or pauses charging to avoid operating the cut out fuse.
This could result in a 60 amp cut out and small service cable being loaded to a full 60 amps for hours on end.
The payback of a larger cable to an EV charger cant be calculated exactly because we dont know the hours of use or future energy prices.
A payback time of some years is in my view acceptable, and may compare well with say double glazing.
If the car needs replacement before payback is achieved, that is not relevant IMO, the cable can be used for the new car.
Converting EXISTING services to three phase could be costly, and I do not propose this unless required. I do however suggest that most NEW services should be three phase. Three single phase consumer units should serve in most cases.
L1 cooker, EV charger, and kitchen ring final.
L2 Electric shower, water heater, second EV charger.
L3 Everything else, including any second electric shower.
Or some similar arrangement.
Otherwise, I foresee a lot of cooked 60 amp single phase services. AFAIK there exists an EV charger that monitors (via a current transformer attached to the meter tail) the total load on an installation. If the load would otherwise exceed 60 amps, then the EV charger slows or pauses charging to avoid operating the cut out fuse.
This could result in a 60 amp cut out and small service cable being loaded to a full 60 amps for hours on end.
