But in the wolrd of Power Companies/Utilities, the IEEE designations are not commonly used. If you look at Cooper utility transformer literature it seems to be based on the type (one or two insulated connections) of single phase transformers which could be used to create the three phase service.
Originally Posted by Jraef
Also, I first sold a slash rated 480Y/277V breaker when Square D introduced their NEHB lighting panel in the early 80's.
Just because you can, doesn't mean you should.