Open Delta for 3phase 4 wire 120/240V service

[fossil112]

Hello all. First time post on here, but I've done a lot of reading thus far.

My latest project has this type of service installed and I'm having difficulty learning how to properly load the panels in the building. This is all new loads, nothing existing.

I understand that I must be careful in determining the panel schedules as each phase can handle only so much load before overloading due to phase imbalancing. This service has the b phase as the wild leg.

My question is how do I properly load the 3-phase panels? This is a maintenance garage, so I'll have both single and three phase loads.

I've read other threads regarding this issue (on here and other sites) and can't seem to find a good answer how to balance the loads.
Is there a definitive answer, or a reference material?
Your thoughts?
Thanks!

reference:
http://www.eng-tips.com/viewthread.cfm?qid=130677&page=1
http://forums.mikeholt.com/showthread.php?t=106976

 

[steve66]

If the B phase is the high leg, all the 120V loads will have to be connected to the A & C phases. I would try to put half of the 120V loads on the A phase, and half on the C phase.

Of course the 3 phase loads connect to all three phases, so there aren't any options there.

The only real choice you are left with would be where to connect any 240V, single phase loads.

Steve

 

[jim dungar]

I suggest two separate panels. Use one for three phase (no neutral pulled), and the other for single phase only.

A little cost up front, but it can save a lot of headaches latter on.