Confused about main panel configuration

I had a professional install a new main panel 200A some about a year ago.
Today I wanted to add a new circuit and when I removed the panel door I was confused to see that both Neutral and Ground are going to the two bars.
Meaning that some circuits have both neutral and ground go to the left bar and then some are going to the right.

Please see picture attached.

Can you please explain....I though only 1 bar is neutral and 1 is ground.
In my case I thought the one on the left (in the picture should be ground).

Thanks!

 

That is a service panel. Both neutrals and grounds can connect to those bars. The neutrals do need to be in a dedicated hole. No sharing allowed.

 

What about grounds ?
I thought they shouldn't be sharing holes either but I see few that are shared.
Is that up to code ?

EDIT: Also, when I add a new circuit and new breaker...do I keep the white and ground on the same bar?

thanks!

 

The panel that has the main disconnect has the Earth and Neutral connected, any sub panels or even the main breaker panel, if different and in the same building don't.

For detached properties the main disconnect is normally outside with one big breaker for the entire supply, it will often have one or two additional breakers for exterior buildings, pool, hot tub etc, the main breaker panel is normally inside in the garage. In apartments the main disconnect can be at the main breaker panel in which case the Earth and Neutral should be connected to each other there.

Although they are connected together at the main breaker Earth and Neutral are classed separately and should not be confused or cross wired at any other location. Neutral is designed as the 'return' for 110VAC appliances, Earth is designed as short circuit protection. The reason the Neutral is connected to Earth at the Main Breaker box is so that any unbalance-able loads go to ground.

As for your specific box, it looks like the main disconnect breaker is at the bottom so this is the only panel that should have E and N connected to each other. Generally that is done with a connecting rod or bar, I can't see how your two green wires are actually connected to each other.

Any 110VDC supply, 110 receptacles etc, should be wired to both the Neutral bar and the Earth bar, and one of the hot legs. Any 240VDC supply, AC, oven etc, should be connected to both hots and the Earth (never the Neutral).

 

Earths of the same size are allowed to share as they have zero potential.

Yes when you add cuircits always maintain the integrity of Ground and Neutral. Whites to white, Greens to green.

 

Private,

Current is not trying to get to earth ground. The resistance is too high. The reason the grounds are bonded to the neutral is so the breaker will trip by having a low impedance path.

Straight 240 volt circuits do not need a neutral. A 120/240 circuit does need a neutral.

BTW, the voltages are 120 and 240, not 110 and 220.

It is more correct to say a service panel is where the neutral and ground bond takes place. A panel can have a main disconnect without being a service.