IIRC, in the EUSERC area (Western States) the upper limit for single phase service is 400 Amps.
If a mega-mansion needs more then it's going to be 3-phase: 208Y120 Volts.
Center-tapped delta 240 is no longer permitted in new installations -- as a rule.
(The machine tool industry has phased out 230V delta motors for quite some time. Dual voltage 230/460 is the norm. So, 480/277 Volt Services are the EUSERC industrial shop solution.)
EUSERC has banned/ shunned center-tapped delta Services because of their higher rate of risk for injury and damage. They are still available -- but only by exception/ convenience to the Poco.
When I look at the Service blues that pop up on ECN photo pages -- I'm pursuaded that the whole country ought to adopt EUSERC standards.
