Sorry, not too smart electrician.
Almost all homes today are 200amp service, many (like mine) have 400 amp service. Many homes over $400k will have 400 amp service.
60 amp service homes are ancient, maybe 1 out of 1,000. Even 100 amp homes are rare, maybe 1 out of 500.
No one who can afford an EV will have a house with less than 200 amp.
Still, 50 - 60 amp charging system is max on a single phase 240v service. High speed charging takes 480v/3 phase service, almost never found in homes - even of the ultra-rich - because it is not available in residential areas. Only commercial/industrial.
Problem is utility distribution system. Expert utility folk say system will collapse when 5% of all vehicles are EV’s.
Only answer will be rolling black-outs, as both Cal and Texas have experienced.
Then, you’ll be so happy with your EV when you don’t have electricity to power it.
The chargers have step up transformers to reach high voltages. Good luck bumping em up to 3 phase. As far as service voltages go, a 400a single phase service is a rare animal in a residential building. The square footage would have to be 10000+.
More likely is 2 200a 40 circuit panels. In areas that use natgas for heating and cooking, a 400a panel is ridiculous.
A 100a sub branched off a 200a main doesn’t mean you have 300a.
Clown.
“Expert utility folk say system will collapse when 5% of all vehicles are EV’s.”
I am sure you can provide a list ...