ECN Forum Forums Code Related Discussion NEC & other Code issues Sizing Conductors for Voltage Drop-K value

K=12.9 Copper

K=21.2 Alum.

Both at 75'C

Single Phase Two wire
Vd= 2K X L X XI over CM
CM= 2KxLxI over VD

Is what I use

I got it out of Ugly's 2002 edition page (48)