Quote Originally Posted by texie View Post
There are a number of reasons why a Y system would be better than a delta (even when there are only line to line loads). Among them, the phase to ground voltage is the same as line to line in a corner grounded system and thus requires equipment rated for this. In this day and age, corner grounded delta rated equipment such as panelboards, etc. is becoming less common. Also much load equipment these days, such as VFDs are not suitable for use in a corner grounded systems.
Given the same 3Ø voltage as a corner-grounded delta, a wye system will have 57.7% (1/√3) line to ground voltage.