Greg here. Just remember that VD is equal to (2) "licks" over a "Cool Mama". Now this applies to your personal life as well as electric work.
The above formula is for single phase applications.
For three phase applications use the following:
VD=Voltage Drop (or it could be you know, V.D.)
L=length of circuit from source to load (one direction only, thus the "2" in the formula)
I=current in amperes
K=constant for either copper or aluminum
Acm=Area of conductor in circular mils (or it could be "A cool Mama")
The .866 is thrown into the formula for 3 phase applications, and is equal to the square root of 3 divided by 2.
The constants for copper and aluminum may vary depending on who you ask, but I was taught that Copper is 10.4, and Aluminum is 17.1.
If you want to avoid "VD" in your personal life, stay away from those "Cool Mamas", but if you want to avoid "VD" in your electrical work use the above formulas, and I'm sure that you will be O.K.
Always, always remember, "Proper electric today, keeps The Watt Doctor away."
And by the way, The Watt Doctor only does check ups on one kind of VD, and it has to do with the kind where electrons, conductors, difference of potential, etc are involved, not the other.
Best Voltage Dropological Regards,