I am working on the relighting of a large prison yard & fence, and have multiple circuits with long conductor runs which I have sized for voltage drop. I have also derated the conductors per number in the raceways. These are 480 volt single phase lighting circuits with a maximum OCPD of 50A. The voltage drop calculations and quantity calculations independently indicate the same size conductor - #2CU.
I am going to use a single EGC for multiple circuits per 250.122(C), and resize according to 250.122(B). I'll increase the #10 EGC size interpreted from Table 250.122 by 640% according to the difference in circular mils between a #10 & #2 conductor.
But my question is - after derating for voltage drop... then derating for the number of conductors in a raceway... would you have to recalculate the voltage drop for the quantity derated conductors? And if so, how?
And then size the EGC by this final calculation?
Thanks for any help!
I am going to use a single EGC for multiple circuits per 250.122(C), and resize according to 250.122(B). I'll increase the #10 EGC size interpreted from Table 250.122 by 640% according to the difference in circular mils between a #10 & #2 conductor.
But my question is - after derating for voltage drop... then derating for the number of conductors in a raceway... would you have to recalculate the voltage drop for the quantity derated conductors? And if so, how?
And then size the EGC by this final calculation?
Thanks for any help!