Bill wrote:
1) Is the 6-3 Romex cable suitable for a feeder cable as described?


I found the following,and thought it was insightful. The way that I
interpret it, using only 2-pole breakers might raise the effective
ampacity of a "50 Amp subpanel" to 100 Amps (of course this ignores the
extra heat generated by having 2 hot wires "filled" at the same time).
Is there any fruit to be picked here?

-Bill



This provides two separate 60A legs of 120V. Usually, each row in a
breaker panel is on the opposite leg from the row above/below it. So if
you want three each of 15A and 20A 120V circuits, and they are all fully
loaded at once (and this rarely if ever happens), your loads will be as
follows:

Leg 1: 20A + 20A + 15A = 55A
Leg 2: 20A + 15A + 15A = 50A
Neutral load: 5A
If leg 2 goes to 0, then the neutral load would be the same as leg 1, 55A.