Separate Building Grounding

[inspector 102]

Main Structure has 200 amp single phase panel with CCE. There will be a 100 Load side panel located in the structure fed by 4-4-4-4 cu feeders. Then there will be a feeder extended to a detached building with a 60 amp load side panel. My understanding is this would also be fed with 4-4-4-4 cable but then also grounded to an approved grounding system via 2-ground rods per 250.53(g) and 250.56. The middle load side panel will have no additional grounding means other than the grounding conductor pulled as the feeder assembly. Am I correct on the application of this since there is a panel between the MDP and the last load side panel. Going to the detached structure has me a little confused. Thanks for help.
Note: I think the minimum size of grounding conductor would be #8 cu for feeders per Tab 250.66, but they have proposed #4.

 

[tom baker]

Sep structures require EGC and GES. Size of EGC is based on 250.122. For the GEC, 8 AWG can be used but requires beinging installed in conduit, use 6 AWG always as a minium and size per 250.66

 

[Dennis Alwon]

The only difference in going to a detached structure and a going to a sub panel is that you will need to use grounding electrode(s) at the structure and the panel will need have no more than 6 handles in the panel unless it has a main breaker or a main disconnect. The panel as Tom said needs an egc based on 250.66-- #6 should work for the feeder of 60 amps.