Solar Edge back up interface and its validity with 705.12

[Designer101]

we have two SolarEdge(7.6 kw) energy hub inverters and three LG chem batteries.
inverters are connected to 200A Back up interface , two back up interface is available one with 200A breaker for creating as service entrance and other without 200A breaker into it. here i have used without the 200A breaker.
we have tried to back up the 225 A sub panel, that sub panel is initially connected to 200A split type 400A Rated main panel.
Since the sub panel and main panel are located greater than 60 ft. apart and at opposite site of building, relocation the Sub panel load to main panel is not so easy and the sub panel breaker cannot be derated to 150 A, we need at least 80A of back feed.
Now how to make this code compliant installation.
A part of me tells me that since we are connecting the back up interface directly to main breaker we don't have to follow 120 percent rule and we can use 705.12 (c), to qualify. I want to take a suggestion before submitting for permitting.
please see attached SLD.

 

[wwhitney]

- Your backed up loads panel will need to have a main breaker, unless you want to feed it with conductors with an ampacity of 280A (200A from the service, (2) 40A breakers from the inverters, on the assumption the inverters are really 7.68KW inverters)

- Do you have an additional 90A of PV that is connected to the "400A" service panel? And do you have any loads in that panel?

Cheers, Wayne

 

[Designer101]

- Your backed up loads panel will need to have a main breaker, unless you want to feed it with conductors with an ampacity of 280A (200A from the service, (2) 40A breakers from the inverters, on the assumption the inverters are really 7.68KW inverters)

- Do you have an additional 90A of PV that is connected to the "400A" service panel? And do you have any loads in that panel?

Cheers, Wayne

sorry that was typo , the main panel doesn't have any solar , this project was changed to battery at last and module count was 53 with 53 IQ 7 plus inverters initially and I had connected to main panel derating the breaker to 150A. Now after adding battery and backing whole sub panel scenario( sub panel is connected to 200A breaker in the upper bus bar of 400A Rated panel)
we cannot connect the back up interface to main panel lower bus bar.
now my option is to derate that sub panel 200A breaker to 150A but it has heavy loads and I am unable to do that, relocating the sub panel loads to main panel is also difficult as the main and sub are not in the same building wall. they are like on the opposite corner 60,70 ft apart and underground wires are feeding the sub panel up to main. the wiring is complicated that 200A ac disconnect will cut of even the house loads when turned off.

Now in this scenario can i consider connecting to 200A SUB PANEL breaker in the main as supply side connection and do not need to derate that breaker to 150A??

 

[wwhitney]

Your drawing does not show a main breaker in the "Existing 225A Rated Subpanel." That panel needs a main breaker of rating not exceeded the ampacity of the 4/0 Cu conductors (230A) to comply with (2017) 705.12(B)(2)(1)(b).

Beyond that, the subpanel itself does not have to comply with 705.12(B), as it only has one source of supply, the feeder. With your topology, you basically just have a 200A feeder from the service panel 200A breaker to the subpanel, and the feeder is intercepted in the middle for the interconnected electric power source. So that's why 705.12(B)(2)(1) is the only applicable section.

Cheers, Wayne