JBD,

Are you sure this also would apply to a 4 wire Wye transformer???
I could see it being done on a Delta 4 wire secondary where X0 is the center tap of one winding, plus the need for L-N loads is much lower than L-L and 3 phase loads.
Also could see a 3 wire Delta, even a Delta primary with a reduced size coil - but that shows how much I know [Linked Image]

To me, this would be an inadequately constructed secondary coil, since the 4 wire Wye is 3 separate 2 wire coils connected at a common point [which becomes the common Neutral, or X0], instead of a center tapped winding. Single coil's rating would be exceeded very quickly.

Let me know your thoughts on this, and if I am out of the world here, please direct me towards something that explains the reasoning behind it [AKA: What 'da heck is going on! [Linked Image]]

Scott SET

Scott " 35 " Thompson
Just Say NO To Green Eggs And Ham!