This article seems to only cover the residential distribution system. I say that, because it covers the single phase, center-tapped 240V (120V-Neutral-120) that

This article seems to only cover the residential distribution system. I say that, because it covers the single phase, center-tapped 240V (120V-Neutral-120) that's conventional in North American residential circuits. However, in commercial buildings, I've seldom seen single phase 240/120V service from the utility. Rather, I've seen 3-phase 480/277V. If 208/120V is to be used, there's usually another transformer on premise to step down the voltages. I wish the article covered how the secondaries for commercial distribution was done as well, but at least its coverage of residential service is informative.