Domestic buildings are provisioned with 240v @ 50Hz single-phase boards, and commercial buildings get 415/240V @ 50Hz three-phase boards. The distribution network depends on the region, but is ...

Panelboards — Since 1975, panelboards supplied by a 4-wire, delta-connected, 3-phase system must have the high-leg conductor terminate to the “B” phase of a panelboard [408.3(E)]. Section 408.3(F)(1) ...