To maintain a max. 3% voltage drop you'd need 12awg for 25ft. I personally would recommend using 6awg with a 50amp breaker in your sub and a 30amp time delay fuse in a disconnect switch. The surge current could be upwards of 30amps and electric motors can not tolerate a voltage drop for a length of time. Sounds like overkill, but it will save your motor.
Last edited by 53ussteel; 01-04-2007 at 08:27 PM.