DrewE wrote:
For conduit, you need four separate wires rather than 10/3 + G cable. The wires need to be rated for wet locations (which commonly available separate wires generally are). So you'll either need to run the conduit all the way to the main breaker box, or have a box midway at some convenient place to transition from the cable to the wires in conduit.
(I think the code doesn't technically forbid using cables in conduit, but it does impose some additional size and derating requirements. Regardless, underground wiring in conduit needs to be water rated, so ordinary romex is out of the question. Pulling individual stranded wires is also a lot easier than pulling multiconductor cable, especially as the cable usually has solid conductors.)
If your pedestal allows for it, and I suspect it probably would, I might consider installing a 50A dual breaker for the main in the house panel and, of course, running the appropriately sized wires for 50A. That way, should there be a desire at some point in the future to upgrade to a 50A pedestal, only the pedestal needs to be changed.
This works as long as the pedestal has its own breakers for the 30amp and the 20amp.