12 in and 12 out...
Where do you get 6 x 3.5" ?
Right off the bat the bonding run is too small...IF this is one load.
It must be sized to handle the fault current for ALL hot conductors at the SAME INSTANT.
Are you really running 12 x 500kCMIL x 3 hots and 1 neutral?
Or is this a bank of runs to dependent panels off of a bank of independent breakers?
BTW your neutral seems massively oversized -- IF you're driving mainly 3-phase loads.
What does the EE have on his 1-line? Sounds like he goofed.
At these power levels bus-duct or cable-bus (MPHusky) is normally used.
Is this a high-rise building?...
Can you use cable-tray and MC?...
Too many unknowns to take a stab at.
I can say, twelve feeders flat across is a monster rack and ordinary strut is going to sag. You'll need double deeps.
Further, during the pull operations -- don't spare the lube.
Edited by Tesla (04/23/10 03:08 AM)