Sharing ground with generator?

[pr3dict]

So I just submitted my permit application today and I'm not entirely sure my design is ok...

I am looking to install a new sub panel in a new detached garage I'm putting up. At the same time I'm looking to install a whole house 22kw generator behind the garage.

The run to the garage from my existing Main panel is 230' and to the generator is ~260'. So using one conduit run is preferred.

100 amps for the generator. - Because of the distance I need 4/0 XHHW
60 amps for the sub panel. - Again distance 1/0 cable.

So as individual circuits these would be run as 6 individual cables inside the conduit but can I save some money and bond the two grounds together at the junction box like I have shown? As I read up on this it seems that this only ok if the circuits come from the same panel but the generator is going to a transfer switch and the ground from the sub panel would go to the "existing" Main (which will become a sub panel after the ATS is installed)

Any thoughts on this or should I give up trying to save money on 1 wire even though it's ~230 feet of it?

 

[wyliesdiesels]

Generator wires should all go to ATS

You need 4-wires for each feeder NOT 3.

Your picture didnt post because you do not have enough posts yet. You need 6....

 

[Stuart in MN]

The picture didn't show because you need to change the 'https' to 'http' in the address for imgur files to get them to appear:

 

[pr3dict]

ah typo on the 3 vs 4 wire. but my question really boils down to this.

Sub panel = 2 hot, 1 neutral, 1 ground
Generator = 2 hot, 1 neutral, 1 ground

right before the conduit to the house can I bond the two grounds together so I only use 7 wires instead of 8? 4 hots, 2 neutrals, 1 ground?