Correct me if I’m wrong but there is no bus panel here. Working on a bath remodel and running new wires to two new breakers for new GFCI receptacle and one for heated floor. As this is main panel other posts indicate ground can share neutral bus. Should I bother running two new grounding wires to each of those locations and breakers? No other grounding wires evident.
All the wiring is in THHN wires inside metal conduit. Since the metal conduit carries the ground, there's no need for any ground wires, therefore no need for any ground bus.
"That was easy..."
Note that nobody puts in metal conduit for their health. They use metal conduit because the municipality requires it. So if you are DIYing electrical and got all your knowledge off Youtube or books at the store, you may have used the popular Romex/NM cable. If so, you'll have to contact your local inspector's office and ask them what is required, and upgrade to that if called for.
It can be frustrating to have to learn a second method after learning a first one and doing the work... but really, conduit is a much better setup and much more maintainable and easy to change/upgrade. Once you get the hang of it, you'll be smug about using conduit :)
Note that several of the circuits in your panel are sharing a neutral. (twice as many hots as neutrals in some pipes). The breakers on the 2 hots need to have a "handle tie" between them, or, use a 2-pole 240V breaker of that same amperage.
If you really need a ground bar, then the manufacturer's label will specify certain accessory ground bar models which are designed to bolt right into the holes pre-drilled in the panel.
You don't have a ground bus because you don't need one. All existing wiring is in metal conduit, which provides the ground.
If you are in a location where local electrical code requires metal conduit, then by definition all your new circuits will have metal conduit as the ground path.
If you are in a location where local electrical code does not require metal conduit, then you can run either NM cable (including a ground wire in the cable) or non-metallic conduit (e.g., PVC) and include a ground wire. In those cases, you can either install a ground bar or, if this is the main panel, and not a subpanel, land your grounds on the neutral bar.
