I have an instructor telling me that to do a VD calc, you use the following formula: VD=(Amps x 1 way Length x R)/1000'
Where R = ohm/kFt from NEC Ch 9, Table 8
It seems to me like you would have to double the length since we are only counting the resistance in one direction...is this correct? I have always used the online calculators, and I'm trying to learn how to do it on paper.
VD=(Amps x 1 way Length x R)/1000' This would be the correct formula if you are using a 240 volt 2 wire circuit. There is no return distance required. If you have a 2 wire 120 volt circuit then you need to count the return distance in the caculation.
Re: Voltage Drop Calculation #129900 11/09/0510:03 PM11/09/0510:03 PM