On Saturday, May 23, 2015 at 11:22:49 AM UTC-4, HerHusband wrote:
Ivan,

After running two separate circuits for my daughter's dishwasher and
waste disposal, I was told that I could have simply run a three wire
cable (still 2 breakers) from the panel box and fed the appliances
separately. I understand the concept, but, there would be 2 hot wires
and only one neutral. Would not that neutral carry twice the current
it is designed for?

For that kind of "Edison" circuit, the two breakers must be on opposite
sides of the incoming 240V supply. That way each 120V "hot" leg is out of
phase with the other as the AC cycles back and forth. When one leg is
positive, the other leg is negative. The neutral never has more than a
single load on it.

AFAIK, there is no other kind of Edison circuit. The whole point
of an Edison circuit *requires* that it be on opposite legs.