Hello all,
I am working on an underground pull for a 400A service. The total distance is just over 600'. I have worked voltage drop calcs myself and compared to online calculators and either they are wrong or I am (probably the latter). I appreciate any input. Also, (and maybe this is where I'm getting confused), do I double the cmils in the calc if I'm parralleling a set of conductors? If not, how do you account for a paralleled set? And, I want to keep this under 3%. Anyway, here goes,
400' to first j box (the ditch isn't straight so I'm putting in pull boxes)
VD=2x21.2x1.028x400x400/750kcmil
VD= 9.29 (3.8%)
I know that is over 3%, but, I just want to be sure my math is right. If I parallel that 750 do I just divide the VD in half? The 1.028 is the Q factor (for conductors over 2/0) which is a new one for me.
I'll work on the remainder of the UG once I feel more comfortable about the calculation concerning voltage drop.
I am working on an underground pull for a 400A service. The total distance is just over 600'. I have worked voltage drop calcs myself and compared to online calculators and either they are wrong or I am (probably the latter). I appreciate any input. Also, (and maybe this is where I'm getting confused), do I double the cmils in the calc if I'm parralleling a set of conductors? If not, how do you account for a paralleled set? And, I want to keep this under 3%. Anyway, here goes,
400' to first j box (the ditch isn't straight so I'm putting in pull boxes)
VD=2x21.2x1.028x400x400/750kcmil
VD= 9.29 (3.8%)
I know that is over 3%, but, I just want to be sure my math is right. If I parallel that 750 do I just divide the VD in half? The 1.028 is the Q factor (for conductors over 2/0) which is a new one for me.
I'll work on the remainder of the UG once I feel more comfortable about the calculation concerning voltage drop.