Running 4-4inch IMC from a pad mount xformer up the side of a building to a 480 volt 1600 Amp main switch in a second floor electrical room. There will be 4-600 MCM THHN's in each.
The 4 inch LB's (not the extra length ones) say inside they are good for 3-4/0's. Is that all you can fit in 40% of this LB??? I was surprised by this, but had a bit of trouble finding the answer in the 05 NEC.
Probably will have to use a huge weatherproof box (CT Cabinet) to make the transition and run all 4 pipes thru it. Then nipple out the back to the Main Switch.
It is also surprising how hard it is to come in the side of this switch with 4-4 inch conduits...the frame bracing is in the middle of the side panel. 16-600's will be a formidible task.
