What are rules for combination panel load side breaker connections?

[bbcleanenergy]

I am trying to figure out how much inverter ampacity I can tie in on the load side for a 'Square D ALL-IN-ONE combination Service Entrance' panel. Based on the model number:

SU3040D-00CB​

(from what I can make out, it is a bit scratched off) I think this may be a 400A rated bus bar panel. There is both a 200A and 100A service disconnecting breaker (single meter). With this configuration would I be able to tie in 180A? 400A * 120% rule - combined 300A main OCPD? Or in the case that it is a 300A bus, could I tie in to the 100A section (slots 9-15) to tie in 260A on the load side?

Not sure if I am even thinking about this correctly, I have not seen this type of configuration before....

 

[bbcleanenergy]

I am trying to figure out how much inverter ampacity I can tie in on the load side for a 'Square D ALL-IN-ONE combination Service Entrance' panel. Based on the model number:

SU3040D-00CB​

(from what I can make out, it is a bit scratched off) I think this may be a 400A rated bus bar panel. There is both a 200A and 100A service disconnecting breaker (single meter). With this configuration would I be able to tie in 180A? 400A * 120% rule - combined 300A main OCPD? Or in the case that it is a 300A bus, could I tie in to the 100A section (slots 9-15) to tie in 260A on the load side?

Not sure if I am even thinking about this correctly, I have not seen this type of configuration before....

For reference, closest serial number I could find for panel.

https://blackhawksupply.com/product...oVtPhHkWarXUtv1uJgxEpCc0zFP78Q0hoC-iYQAvD_BwE

 

[jaggedben]

What you've got there is two 200A service disconnects, one of which feeds a 200A panelboard. So by the 120% rule you can backfeed 32A (inverter continuous output) on the panelboard section, and/or 160A on the additional 200A service disconnect. The additional disconnect can essentially be used as a supply side connection up to the SQ-D allowed rating.

This isn't well explained on the label but I've gotten clarification from Sq-D.

Note that that panel is no longer compliant with the NEC as of the 2020 edition, but if it's existing the AHJ may grandfather it.