2 sets of parallel service conductors - same conduit

[housemoney]

Sanity check for me please: Contractor has (6) 600kcmil ungrounded conductors and (2) 2/0 grounded conductors per 5" conduitI calculated a minimum of 450kcmil grounded conductor with 12.5% rule? 2 -2/0's are not cutting it correct? I know you're required to run one per conduit, but is it permissible to run 2 smaller grounded conductors for a sum of 450kcmil?Thank you.

 

[infinity]

You can parallel conductors #1/0 and larger. Can you show your calculation for the 450 kcmil? I get:

600,000 cmil * 2 = 1,200,000 * 12.5% = 150,000 cmil

 

[texie]

I'm not understanding where the OP is getting 450 KCMIL either. I would also question, if all conductors are in 1 raceway, why he is using more than 1 grounded conductor. My math shows a single 3/0 would be correct. As we know there are big downsides to using a single raceway for parallel conductors but this is one of the few advantages.