As long as we are talking about panel that comprises the main service, then it's perfectly fine to terminate the ground wires and "neutrals" on the same bar. Some people prefer to keep them separated on different bars, and that's fine as long as both bars are connected to the service neutral conductor. An example would be some panels that have neutral bars that run down both sides of the panel. Now if this were a sub-panel, then no, the ground wires and "neutrals" must be kept separated all the way back to the main service panel.

This is because if, for some reason, the neutral between the sub and main panels came loose or apart, the voltages that the neutral should be carrying now end up going back out over the ground wires for every circuit in the sub panel. This also means that ground pins in receptacles, face plate screws, appliance frames, just about anything metal could and probably would become energized.

By keeping neutrals and grounds separated at sub panels, a failed neutral becomes simply an inconvenience, not a shock hazard.

Is that clear as mud?


---Ed---

"But the guy at Home Depot said it would work."