Doug Miller wrote:
.... To be Code-compliant, at a minimum, the two 30A circuits would
have to share a
common disconnecting means (i.e. throwing *one* handle turns off
*both*
circuits simultaneously).

I can't imagine that what you propose is permitted by the NEC, but I
can't at
the moment find anything in the Code that explicitly prohibits it.
The closest
I can come is:

"In no case shall the load exceed the branch circuit ampere rating."
[Sec.
210-23, 1993 NEC -- the most recent one I have at hand.]

That's a good point about having one breaker turn off the circuit.
I'll be sure to do that. Perhaps I'll have to run a single cable
rated for 50 amps rather than having the conductor split, so to speak.
The only other alternative would be to have a 50 amp breaker at the
service box that then splits into the two 30 amp runs, and the
recombines at the end to the 50 amp cable, taking into account proper
derating factors.