Voltage Drop

[dav5y]

Hi All,

I have a voltage drop question. I have eight (8) 255 Watt fixtures at 277V with the first fixture being approx 200 feet from the Panel. My question is, do I calculate voltage drop using just the first fixture load (1 fixture) at 255 Watts or the total load of 8 fixtures at 2040 watts ???? If it matters, the lighting fixtures are mounted in an aisle configuration.

 

[don_resqcapt19]

You make the calculation based on the load on the conductor at that point in the circuit. For the voltage drop on the home run, that load is all eight fixtures. Then you look at the voltage drop between the first and second fixtures using the load of 7 fixtures. Remember that the stating voltage for this section of the circuit is in addition to the votlage drop on the home run. That is you add the home run voltage drop to this newly calculated voltage drop to get the voltage at the second fixture.