4000A Grounding

[confused123]

We have a 4000A ATS that is about 150 feet away from our switchboard, it's located on the same pad as the gensets and the utility transformer. Per NEC 250.122 we need a 500 kcmil EGC. We are using (11) 4" conduit to run (33) 500 kcmil conductors, we don't use the neutral for any loads so we are omitting it after the service entrance at the ATS. With this setup we will need a 500 kcmil EGC in each conduit, so we will be running (11) 500 kcmil EGCs.
My question is if anybody knows of an expectation in the NEC where we don't need an 500 kcmil EGC in each conduit or if someone has another idea how to make this 150 foot run more efficiently?

 

[infinity]

About the only way to eliminate the 500 kcmil EGC's is to use a metal conduit as the EGC.

 

[electrofelon]

I assume this is underground? What about direct burying and skipping the conduit all together? 4 dump trucks of sand is probably a lot cheaper than all the conduit, pulling labor, and 10 additional EGC's. USE will be a bit more than TH or XH but it may be worth it.