cctalk Digest, Vol 88, Issue 2

[Jonathan Chapman]

> I have seen some roads where the utility has 2 of the phases plus
> neutral going down them, not true 2-phase power, but 2 phases 120/240
> degrees apart with the third phase just not present.

Yes, that's open delta. There are one or two small commercial buildings here in town that still have open high leg delta service -- that's 240V delta, and one of the 240V transformers is center-tapped to give 120/240 split phase for small loads.

My guess is, aside from saving on wire, insulators, etc. (not significant in town), the real savings is on disconnects and the extra transformer.

Thanks,
Jonathan