Neutral and Ground Bonding at Main Panel

[bilbrelb]

It's my understanding that Neutral and Ground are normally tied together once they come into the main panel and only in the main panel.

When I look at mine, I have a ground coming in from outside to the ground bar (Lower left of image). Nothing is connected to this, not even the neutral.
I see another ground wire connected next to my neutral wire (Connected together see upper middle circled in image) but it does not go to ground bar in panel, it goes across the floor joists and to the water meter on the street side.
All whites and grounds go to neutral bars.

So I assume this is the same as tying it to the main panel ground since both the ground bar and the neutral are eventually getting out to ground? I just thought usually the neutral and ground should connect together in the panel.
I know this was inspected back when I had electrician upgrade my service to 200 amps.

I'm putting in a spa sub-panel and wasn't 100 percent sure if I should put the sub-panel ground on the ground bar or the neutral inside the main. Doesn't appear to matter there.
Is this correct?

[suemarkp]

That green screw on the right just above the neutral bar is your "main bonding jumper". This connects the neutral bar to the panel chassis. If other bars are bolted to the chassis, they in turn would be connected to the neutral via that green screw. So even though you have multiple neutral bars, and perhaps other bars bolted to the panel chassis, they should all be "one" because of the green screw.

Sometimes, it isn't obvious what that green screw is bonding. Typically, the neutral bars (if more than one) have a bar between them, so one green screw does it all. However, some are different so that one bar is ground (bolted to the chassis) and one is neutral (isolated form the chassis which you'd need in a subpanel). If I get a new panel I'm not familiar with, I'll look at it closely or use an ohm meter to verify which bars are in fact connected to each other and what the green screw isolates. Once wires are installed, you typically can't measure anymore to answer those questions.

Sometimes, I'll run a #6 green wire across bars to make sure they are well connected. I don't like relying on a metal chassis for a bonding connections as they can get eaten away after multiple large current faults.

[bilbrelb]

Ah, that makes sense then that the green screen is bonding neutral to the chassis. I feel better about it now

So my subpanel for spa, I'll just follow suit and hook both ground and neutral to the neutral bar in the main and keep them separate in the subpanel.

Thanks for the information, appreciate it.

[joed]

I'm not to clear on your spa plan.
The neutral and ground should be connected together only at one point, the first means of disconnect in house. All other panels are sub panels and the neutral and ground are kept separate.

[bilbrelb]

Correct. I ran green to ground on subpanel, white to neutral, then red and black to the hot lugs.
I did not connect the rod in the sub panel that would have connected grounds and neutral so they are separate at the sub panel.

Here is my final wiring in my spa panel. The feed from house is the right 1 inch conduit and the left 1 inch is to the spa.