But already on our lane a householder has been told by the DNO that he can have either a car charger or a an air source heat pump, but not both, unless he pays £25k towards an upgrade of the local transformer and 3 phase power to the house: one phase for the traditional supply, one for the heat pump and one for the car charger.
That's not how the grid works - if he has been told he has to have 3 phases (which is understandable if you were going for a 10kW+ heat pump and a 11 kW EV charger and the existing 100A house load) then it means that the combined loads are spread evenly over the 3 phases, so each phase will consume roughly a 3rd of the load.
He would also need to allow for a new consumer unit in the house as the current single phase unit would need to be replaced by a 3 phase unit with all the house loads re connected to provide an even load over all 3 phases. Or rather that's the way it should be done...
