On Tue, Jan 4, 2022, 18:15 Jonathan Chapman via cctalk < cctalk@classiccmp.org> wrote:
> > High-leg delta exists so you can have 120/240 lighting and appliance loads > in a building that consumes mostly 3-phase, like a machine shop with an > office. In most areas you aren't allowed to have more than one type of > service to a building (not sure if that's true for double-fed sites, never > seen one with two kinds though). I've heard the Power Company usually > doesn't want to install high-leg delta anymore for a variety of reasons: > the load limit, people not understanding they need to skip a breaker, > 120/208Y having become the usual form of smaller service three phase, etc. For what it's worth, the building I bought has two services installed when it was built in 1921 - single phase 120/240 for lighting loads, and 240V Delta for three phase loads. It's the even more obscure corner-grounded delta, which requires even more care and can't provide 120V power, since the phase to ground voltage is 240V. Patrick Finnegan