Panel Schedule, phase load calculation

[QUF]

How to calculate a Phase load on the Panel Schedule? Loads are 4x30hp motor and 2x 10hp

Panel board is 480v, 3p, 4w, 400A.



Thanks,

 

[charlie b]

Look at NEC table 430.250, and find the current values for the motors. Use the 460V column. Multiply that value times 480 volts and again by the square root of 3 (about 1.732). That tells you the total KVA for the motor. Show one third of that value on each of the three phases. Do the same for the other 5 motors.

 

[QUF]

Thank you sire,
I did that just to confirm,

40 (30hp)x 480x 1.7= 32640
32640 /3=
10880 pA
10880 pB
10880 PC

is that right ?

 

[charlie b]

You have the right idea. I would suggest using a number that is closer to the actual square root of 3 than just 1.7. Even using 1.73 would get you a bit closer. The difference is just under 2%, so I would not make a big deal of it.