Bonding conduit going to 2meg gen

[Mustang125]

I have 8-4" rigid pipes going underground to a 2meg gen. I have bonding bushings on them but was wondering how to bond them. The equipment ground is a 500mcm. Can I put a ground bar in and jump to each bushing with a smaller wire? How would I size that wire? Can I come out of one pipe and use lay in lugs and hit every pipe with the same wire? Or do I need to come out of each pipe and hit its bushing with the 500?

 

[Smart $]

I have 8-4" rigid pipes going underground to a 2meg gen. I have bonding bushings on them but was wondering how to bond them. The equipment ground is a 500mcm. Can I put a ground bar in and jump to each bushing with a smaller wire? How would I size that wire? Can I come out of one pipe and use lay in lugs and hit every pipe with the same wire? Or do I need to come out of each pipe and hit its bushing with the 500?

Depends on where the system disconnecting means is located. If at the generator, the equipment bonding jumper is sized per 250.122 [see 250.102(D)].. and yes one can be cascaded to all the bushings. In this case the grounding conductor in each raceway is an EGC sized per 250.122(F).

If the disconnecting means is located at the load end, sized per 250.102(C)(2). Please see that section for the details as it depends on whether you run a single SSBJ or one in each raceway.