I have a #3 THW Cu, 3wire 120/240v single phase feeder 219' in length. If I wanted to find the Ampacity per phase I should use this formula right?

I= VD*CM/D*K

CM- cmil of 52,620

D- 219'

K- (approx) 25.8

VD-(Voltage Drop) should I use 120v or 240v to get my 3% from 210.19(A)FPN:

why use one over the other? If this is a stupid question I'm sorry, I just don't understand

I= VD*CM/D*K

CM- cmil of 52,620

D- 219'

K- (approx) 25.8

VD-(Voltage Drop) should I use 120v or 240v to get my 3% from 210.19(A)FPN:

why use one over the other? If this is a stupid question I'm sorry, I just don't understand

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