How is electrical energy delivered to the end users?

End users generally subscribe to an electrical service according to their power needs.

A residential home, for instance, might have a three-wire, 220-volt, single-phase service rated at between 60 and 200 amps, to a service panel supplying 110-volt and 220-volt branch circuits.

A commercial end-user may need three-phase 277/480-volt system supplied on 4 wires, rated for 800 amps overhead or more underground.