I have a 3 Phase 4 W 1600A Over Head Service going into a Pull Section then
there are 2 service Over Current Device,one is 1200A and the other 400A.
The largest phase conductors are set of (3)750 Kcmil per phase.
I applied 12.5% x 3x 750 Kcmil which equals to 281,250 Kcmil,because phase conductors are over 1100 Kcmil per 250-28(D).I came up with a MBJ size 300 Kcmill. Is this right approach or based on Table 250-66 the max size shall be 3/0 regardless of service phase conductor.
Thanks
there are 2 service Over Current Device,one is 1200A and the other 400A.
The largest phase conductors are set of (3)750 Kcmil per phase.
I applied 12.5% x 3x 750 Kcmil which equals to 281,250 Kcmil,because phase conductors are over 1100 Kcmil per 250-28(D).I came up with a MBJ size 300 Kcmill. Is this right approach or based on Table 250-66 the max size shall be 3/0 regardless of service phase conductor.
Thanks