High Leg Delta with no Ground
The metal conduit, in good order, is the ground

This tends to gobsmack people with residential experience when they first see a commercial installation.  I have four buildings with less than 30 feet of green or bare wire in all of them combined.  You'd think it was an obsolete ungrounded installation, but actually the grounding is modern. 

Working in conduit is nice... Means never having to think about ground.  

It also breaks you of the bad habit of thinking of ground as an afterthought-- e.g. where someone hooks up the conductors, tests and passes, hooks up grounds at the end, and it fails.  He's like "why is my ground defective?"  Which is an upside down view of the problem obviously.