In article , Puckdropper puckdropper(at)yahoo(dot)com wrote:
If you're running 2 120V circuits from a 12-3 cable, consider that the
neutral would have to carry twice as much current as it would in most
situations.

No, it doesn't, unless it's installed improperly. Properly installed (with
the two hot conductors on opposite legs of the service), the current in the
neutral conductor is the *difference* of the currents in the two hots, not
their sum. For example, with 11 amps on one leg, and 7 amps on the other, the
current in the neutral is 4 amps, not 18.