Now that Ron has pointed out the section that covers overload protection of transformers, I see that I was far too conservative in my breaker ratings. [Linked Image] Good job, Ron! (Although, I don't know it those are the right answers, either. But at least they're reasoned from applicable provisions in the code.)

I note that, unless there are high harmonic currents, the neutral on the secondary doesn't count as a "current-carrying conductor", so there are only three CCCs in that conduit. [Linked Image]