isolating phase on new service

[tipton1133@yahoo.com]

i have recently tried to build a 1600 amp service in garland tx ...4 runs of 500 to ct from transformer(garland) power...out of bottom of ct can to 1600 amp disco nema 3r...asked if i could isolate the feed from garland power to ct in 4 runs emt to ct ..thru cts to disco so i could pull a single phase thru cts to disco ...because its 500...got approval from city inspector...got it from garland power ...but humphreys electric not sure if we could ...wanted to isolate the phases because trying to pull 500 (4) different wires thru cts (500) was to say the least a joke and it finished like that ...done this in washington state several times in my 40 career...has any one else done this:happyyes: ?????

 

[infinity]

You cannot run each phase in separate EMT's. Also your 4 sets of 500 kcmils is too small for 1600 amps.

 

[JFletcher]

Welcome. I'm not understanding why with 4 conduits you'd isolate phases anyway. ABCN, ABCN, ABCN, ABCN is the same pull as AAAA, BBBB, CCCC, NNNN, is it not? Also, as mentioned, 4 sets of 500, even without derating, is 1520A, not 1600. Wouldnt isolating phases here bring on derating with 4 CCC per conduit vs ABCN's 3?