I guess this is the place to bring this up:
Most old timers (of which I am one) would not install a single phase breaker in a 3 Phase delta panel where one of the phases is center taped and you have a high leg with 208 to ground.. There are several reasons for this other than the obvious. First of all it's not a violation when you don't involve the high leg. Second of all, you will have a problem if the circuit is 240v and you use the high leg. (see 240.85). I typically would install a 3 Phase panel rated 240/120v for the 3 phase loads and then a single Phase pane; rated 120/240v for the single phase loads and then you will never have a problem with the high leg.
If you have a single phase 240v. breaker with a "slash rating" the higher voltage is the voltage line to line and the lower voltage is phase to ground. If this helps.
