OK, so last question. I have seen 3-phase services where the single-phase systems that have been pulled off the 3-phase gear were done using three-phase breakers and just running a pair of conductors off the two 120 legs. Seems like a waste of a breaker to me. Is there any switchgear you are aware of where the system main busing is three pahase, with a combination of busing where you can pull single-phase secondary feeders off the system?
Seems like somewhere someone should have a need for that and the mfrs have come up with something like this.
Thanks.
Bob
If we are talking about panelboard type distribution equipment on a hi-leg system, and you want to connect a 1? load, you can simply use a 2-pole breaker. However, for 120/240V split-phase circuits, they must be in the C-A positions (B being the code-compliant hi-leg)... and can be 'slash'-rated breakers. Any breaker connected to the B leg must be full 240V rated. And more to the point, I don't know of any two-pole, 3-space breakers offhand...
This issue is part of the reason I wanted clarification on 120 or 240V lighting. With the latter, you could pull circuits off with either 2-pole breakers and better balance the loads on a 3? service, and run 3? subpanels.
An alternative is to supply two mains with the SE conductors: one 3?, the other 1?... but will likely have to use MCB if panelboard type. Using MLO would likely put you over the six-disconnect rule.
Another approach is to get approved for two services: one 240V 3? 4W and one 120/240V 1? 3W. You could then use MLO mains with 6 breakers each. But POCO and/or AHJ may be uncooperative in this approach. And monitoring usage per suite is another issue if the AC units are divvied up.