I see that most of us (including Mike Holt) use the old formula for computing voltage drop. VD = I*K*2*L/CM (change 2 to 1.732 for 3 phase). "K" has been defined equal to from 10 to 12 for copper and from 17 to 21 for aluminum.
Wouldn't it make sense for us to change to the charts used in the NEC for these computations? Chapter 9, Tables 8 & 9 give a hundred different values for "K" (you have to do the math). Could it be there is a more accurate method of doing our computations?
VD = I*2*L*R/1,000 the value of "R" would be determined from the Table. Use Table 8 for DC, and Table 9 for AC, (using Effective Z at 0.85 PF for Uncoated Copper Wires as "R")
BTW, coated wires are varnished wires used in manufactured transformers and coils and the like.
