Re: Service Panel Grounding: IMO: that service panel would be the #1 place to ground, and then connect all other grounds to that. If you are not familiar with wiring a service panel, study up and get help when needed. Re Ground wires in a service panel: This part might be confusing at first to a newbie/ initially looking at inner part 120vac service panel. Unless some unknowledgable person wired stuff up before you got there; the Black (or Red) colored (sheated) wires are for the Hot 120 ac current going to a circuit breaker matching to that wire size; and all the White 120vac neutral wires (in my panels) are all connected to same gound bars as the ground wire. The ground wire are usually bare copper while the 120 vac white neutral wire are sheeted and usually colored White. That bus bars inside your service panels, that clamp white wires, and bare ground wires together ( via wires inserted through holes and tighten down via screws) all get connected to a right gauge size ground wire often sheeted in green, stretched out and connected to a good ground via a nearby cooper rod in ground. If this sounds like Greek and/ore new lessons, study harder to understand more specifics. I have seen some sunset book explain all about it with basic diagrams and good basic language explanations. I also see someone left ya a web info link. I am wondering if you are wiring an off grid cabin, or RV, and not connected to grid power , or will be connecting to grid.
IF you are connecting to the grid, and/or planning to wire any 220 - 240vac circuits from your service panel circuit breakers, and considering wiring your own service panel, you will have study hard / to understand how the two biggest Hot wires and one Ground coming into your service panel, connect to 2 different hot 120 ac current bars in panel / w an incoming ground also going to the ground bus bar or bars; and how all the white wires and bare wire connect up with to each other and ground, via those same grounding bus bars. ... From the looks of your diagram, I recommend you seek more hands on type /experienced help (like an experience friend to double check before your service panel gets energized. If grid tied, best done with a permit, and get the inspection. If you are off grid, and only planning for only one 120vac Inverter line in, and possible a generator line in to service panel, and 120vac lines out through circuit breakers matched to wire size, ...your wiring might be simpler, but you have to feel confident about handling All the Details before flipping on the power. Study up and get answers to all your curious questions answered. If this sound like Greek, study harder and get some help. Best Wishes in All Ways form not claiming to be expert ... :+) Bill