&Kw chargers need a EV charging point put in. Not sure if they user 3 phase for themThe normal domestic supply for an average house in an area with gas supplies for heating is set at about 3KW average and 6KW peak. The substation and the main feeders will be scaled for that. That does not stop an odd house taking more that, provided the neighboring hoses take less. Some users like myself (single and careful) use less typically between 4 and 8 units a day. My maximum usage is a 7KW shower that is only used for a few minuets a day.
However if most the houses in my road start putting 7KW chargers on simultaneously for long periods the feeder cable to the road and substation could overheat and fail. This could be worse in some area where there has been infill development or more hoses added, for example a large hose demolished and a block of flats built in its place. With increasing efficiency of domestic appliances such as LED lamps they have been able to get away without major work. However if many of these houses start fitting electric car chargers overload problems could occur and they may need to replace the cables in the street and the substation transformer
No expert on the local grid but you can be sure the cable to the substation is not rated for every home to use near a 100A nor will the substation be rated to take that load
Most home now will have a shower it may be electric or may be gas. An immersion heater takes a hefty load as well but they tend not be used that often as the gas will be heating the water normally. Another big load is cookers. Increasingly people use electric ovens. Hobs tended to be gas as eclectic was not so good but induction hobs have changed that and more and more people are using electric hobs
Yoy dd al the other things up in the house and it is quite a load. Lighting. TV. Computer. Fridge Freezer, Washing machine tumble drier etc
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Actual data indicates 1 hour for a full charge. The range as well very much depends on weather, load in car and whether heating etc is in use. An EV should not be charged above 80% or run down to less than 10%