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According to my last electrics post I noticed I needed to connect all of my ground wires to a grounding bar. I’ve done that. Now I need to know if I’m okay with just letting it be as is or if I need to run another wire up to my conduit to connect the grounding bar to the conduit (since I’ll be using the EMT as a ground source since it runs back to the meter head).
Yes, you have to have your load center (breaker panel box) grounded. The bar you installed connects all of the ground lines to the box itself. That connects to the conduit, which may be adequate, depending on how it's connected outside. Running the ground only to your meter is not enough. You have to have a ground rod or (in the case of a slab foundation) a connection to the rebar in your foundation. Depending on the size of the building and distance to the meter, you may require two ground connection points.
Caution: Electrical codes do vary from place to place, so take any answers you get here and check them against your local codes. Even though all 50 states have adopted NEC (National Electrical Code), they may not have adopted the most recent version. They also may have exceptions; the state I live in adopted all of NEC 2020 except for some of the kitchen provisions for ground fault & arc fault breakers.
Most electrical inspectors I've encountered are willing to answer questions over the phone or email if you've done your homework first. If you ask about things that are in NEC, they'll probably tell you to either go look it up or call an electrician. You can read the NEC for free online at https://www.nfpa.org/codes-and-standards/all-codes-and-standards/list-of-codes-and-standards/detail?code=70
Since we're talking about a 240V subpanel here, we don't need any extra bonding jumpers to connect the incoming EMT/fitting to the metal cabinet, just appropriate removal of paint + suitable locknuts, as neither NEC 250.92 (service entrances) nor 250.97 (voltages over 250V) apply to this situation. We also don't need to worry about the grounding bar's connection to the cabinet provided it was mounted as per the manufacturer's instructions, and UL has made sure those are sufficient as part of their testing. Finally, NEC 250.109 expressly permits metal enclosures, such as your loadcenter cabinet, to participate in the ground-fault current path, so we have a continuous and Code-compliant path from the ground wires landing on the bar to the incoming EMT being used as a grounding conductor for the feeder, and no further work is needed.
"ground rod" refers to the rod outside that is pounded into the ground to ground the entire system.
The rest are ground paths, which may be either ground wires or (in older systems especially) the metallic conduit.
Metallic conduit is grounded by its mechanical connection to the breaker box, which is itself grounded. For non-metallic (NMC cables), the ground wire provides that connection and must be connected to the ground bus inside the box.
