Now with pictures!
This is how my panel looks with the Emporia installed in it a few months ago before I cleaned it up and corrected some things:
The primary CTs clamp on the main feeds to the top of the breaker panel. The two hots go to breakers that are fed from different phases. Typically this is a double pole breaker like mine is at the bottom right. The others go to the neutral bar. Then there is a WIFI antenna you pop out of the side of the box which you can see in this image.
In my region, code requires a physical disconnect within 6' (lug to lug) for service main from the meter. So I had to have my meter moved from the area on the right to the wall it sits on now. 400A service in the middle that feeds the two disconnects on either side. My Tesla Gateway is the primary disconnect on the right with the "standard" 200A disconnect on the left. Far right in the image you can see the required PV disconnect as well.
Based on load calculations and the fact that I had four breaker panels they determined I required 400A service. Because I ran the Emporia for a few months (total) I knew that wasn't true. I was certain it wasn't true but how can I argue with master electricians and load calculations? Well, since I had the data I took matters into my own hands and resolved the problem myself.
This is my panel setup before the solar/Powerwall install:
200A main panel on the left fed the two middle sub panels plus other high current items.
Here are my breakers panels now:
Far left is the Span Panel that is fed from the Tesla Gateway. The middle two sub panels are fed from the Span Panel as 90A and 70A feeds (Span Panel has a 90A breaker limit). The far right is the original 200A main panel fed from the left hand disconnect in the earlier picture above. Notice the
physical interlock on the far right panel? Well, I couldn't get the electrician to direct wire the one panel to the other because load calculations... but I could get him to install a NEMA 14-50 outlet off of the Span Panel. So I installed a generator inlet, the interlock and a 50A breaker on the main panel (far right). This allowed me to be able to feed the main panel on the right from a generator. What electrician is going to fight that?
Well, my generator ended up being the Span Panel thanks to the NEMA 14-50 outlet installed that matched my generator cable.
So my service main on the far right panel is off and the 50A inlet is on meaning my far right panel is being powered by the inlet. That panel is lights and outlets now. All the major loads were moved to the middle left sub panel or Span Panel. Like, right at this very moment that far right panel is pulling 238w total.
If you notice in the image of my panels, that outlet is gone and I've spliced the wires directly so no more generator cable laying on the basement floor:
So the generator inlet is gone and the NEMA 14-50 outlet is now just a splice.