NEC code specifies that my 200amp main will only be allowed to handle a 40amp backfeed from a PV solar array. I need more than 40amps. I want to upgrade my main panel to 400amp and derate the main breaker to 200amps. Is this an acceptable approach? Are all 400amp panels 3phase. I believe my current service is 2phase, this is residential.

Residential is single phase. A 400amp panel is still single phase.

The code section is NEC 705.12(D)(2)...
You are limited to 120% of bus rating of the panel. Check the label on your panel, some are rated at 225 amperes...
You could install a 200 ampere main circuit breaker panel with 225 ampere rated bus that would allow a PV input of 70 amperes...

Single phase panels are available in many different sizes and ratings from different manufacturers.

I have a picture of the label, There is no way to put that into a reply. How can I get the label picture to you? I think it is stuck at 200amps but I would like a trained eye to verify it.
Thanks

Post a picture. Click on the "Go Advanced" button.

Label attached
Attachment 47118

See the top left corner... "200 amperes maximum"
How much do you want to connect to the panel?

Quote:

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Originally Posted by hfcarson

See the top left corner... "200 amperes maximum"
How much do you want to connect to the panel?

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80 amps from a PV solar array.

Have you read the electrical code to consider any of the alternatives?
by the way...if my math is close, do you have around 100 solar panels?

Quote:

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Originally Posted by hfcarson

Have you read the electrical code to consider any of the alternatives?
by the way...if my math is close, do you have around 100 solar panels?

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No, they are 315watt panels, there are 60 panels.

I could degrade the main breaker to 175amps. I cannot find a 175amp main breaker for a Siemens panel. Does anyone know where to get one? Or does a 175amp even exist?