ECN Forum Forums Technical Discussion Electrical Theory and Applications Phase shift on transformers

That's because nobody ever runs a 240V WYE, there's not much point. (Wouldn't surprise me if there are a few out there, though!) If it's (normal) delta or wye, it's going to be 480/277V or 208/120. But if there was a 240V wye, it would be 240/139V.