Many larger Apt. buildings (Some of which I have done) have 3 phase 208 wye as a service for mixed commercial/residential, or even all residential if large enough. But the resi units only get two of three phases at the panels. All common areas and commercial units get 3 phase.
A guide to rules for such are at the last 2 pages of this doc.
PGE doc Edited to shrink page
[This message has been edited by Roger (edited 01-21-2006).]
