The other place to look is typical info from the pump manufacturer. As many pumps use Franklin Electric motors, taking from the "Aplication-Installation-Maintainance" manual, assuming that 5hp, 1-phase, and 240 VAC is correct, then for 450' from the service entrance to the motor they recommend #6 AWG minimum. This is for 5% Vd, for 3% a #4 is close but you would need to go to a #3 AWG.
The 27.5a would be maximum service factor load for "FE's" 5hp. The pump is rated for 3.7 KW and >0.97 power factor running.
I highly recommend getting the pumps data and verifying these numbers versus taking a wild guess on to little data.
Shane
Last edited by sabrown; 10/03/07 10:15 AM. Reason: Added voltage drop info.
