Craig,

First, I would run the new sander on the circuit you have. If the shop/house is wired correctly*, and it draws too much then the breaker will trip as it should, go protect the wiring and you will know for a fact the draw exceeds the breaker capacity, and likely the wire rating.

You say the sander draws 30 amps- that really means nothing unless accompanied with qualifiers- is that starting, under no load, under normal load, under max load (FLA- full load amps), etc. I suspect under normal load it draws less than that.

* I don't mean to criticize, but judging your questions, you should consult a certified electrician before doing anything, and maybe have him do the work.