bonding jumper sizing and duplicating condutor purpose

[mooreaaryan]

I have a 600 amp main fed with parallel 500mcm with a 1/0 ground per bundle. Entering the main I have a double barrel ground for the ground supply side, then I have a double barrel ground lug for the load side taking the load side 500s and the 1/0 grounds to a distribution block. At the distribution block I have two ground bars bonded together with the 1/0 attached to that is attached to the gutter by bolt and nut. Out of these ground bars I have 4 service disconnects and a mini load. each service is 3 phase 480v (motors) and mini load is single phase, each service has a separate ground that is in a lay in lug that is attached to the panel board by a tap and bolted in the disconnect panel. The mini load in terminated to ground bar in termination area. The load side of all service panels has BOY out an overload, and an equipment ground originating from the panel backboard on a lug thats been attached tapped paint removed out to the motor peckerhead , My issues is can the Equipment grounding conductor serve as a bonding jumper for the conduit that's in between the gutter, by attaching it the grounding bushing on the conduit, and the service panel? the knock out of the service panel is a concentric knock out and the gutter is a knock-out that we did.

 

[augie47]

If I follow correctly, your gutter is bonded by a ground bar bolted to the gutter and you nipple between your main and your gutter has "punched" knockout on the gutter. If that is correct you do not need a bons bushing at all but if you want to use one, an equipment ground can be used to bond them
(you use the term "service" but I'm reading as if you have a 600 amp Main. If there is no main, the situation might be different.