High leg question

[LarryFine]

My question, concerning all this discussion of the "High Leg," is, why does the Code allow this type of installation at all? It seems to me that the three phases would go into a gutter, there would be a 240/120 panel for single phase loads, and the three phase loads would be in individual disconnects hanging off of the gutter. There must not be enough of a documented body count to get the Code to disallow this. This is one change i'd like to see in the 2011 Code.

I don't agree with your position, but for good reason. You're looking at the evolution of electrical systems from the present, but that's not how things have progressed through the years.

If you ignore the high-leg transformer(s) and conductor, what remains is exactly the same thing as a typical 120/240v 1-ph 3-wire supply. I don't believe this is a coincidence.

High-leg 3-ph (open Delta) systems originated by adapting existing 1-ph systems for 3-ph, simply by providing one more transformer and primary conductor.

If you think back to the "Delta breaker", it didn't even receive its third line from the panel bus, but from an external fourth terminal. The high-leg's supply was brought into the panel by an added conductor.

Today, nobody asks for a high-leg service. We get either Delta (if we're distributing big power and expect to supply large loads and/or transformers) or Y (if we're supplying mostly line-to-neutral loads).

But, to outlaw high-leg services implies condemning existing services, not preventing the installation of new ones. The only time I've installed new high-leg panels is when using existing services.