Calculating Voltage Drop for 200HP Motor at 480V

[vptran84]

Hi,

I was wondering if anyone can help me figure out how much voltage drop is happening in this particular scenario.

Here is my work:

Given 200HP motor at 480V that is 300 ft. away from the starter.

%VD(3phase) = [12(1.73)(300ft.)(240A)]/[(Circular mil) * (480V)] x100

I use 12 for copper, and with 200HP the Full Load Amp is 240A.

I have no idea where i can get the circular mil. Can someone please help me. I know that it's somewhere in the NEC.

thanks.

 

[nik282000]

You have to look it up in the American Wire Gauge chart (AWG). Take a look here http://www.google.com/search?hl=en&q=wire+gauge+chart&btnG=Google+Search