5.75kw solarsystem connected to a 100 amp Panel via combiner panel ?

[Naptown]

Your new solar electric system will need at least two open slots in the breaker panel for the solar feed. As a general rule, the main breaker needs to be 200 amps or larger. If your main breaker panel is 100 amps or less, has fuses instead of breakers, and is in generally in poor condition; you may need a main panel upgrade as part of you solar installation. Your solar installer will make this recommendation if needed.

Actually you are limited on a backfeed breaker to 120% of the buss bar rating.
If you can find the model # of your panel and the manufacturer you may be able to determine the buss bar ratings from them (hint look inside the panel for the label by taking the cover off)

[Volusiano]

I have 200A service but when they put in my 11KW system, they had to derate my panel down to 150 (could have derated to 175 but they didn't have the 175 breaker) because they backfeed 46A into a 60A breaker on my panel.

I don't know whether the breaker size is the limiting factor or the backfeed amperage from the system is the limiting factor. If the later, then in your case, even though the breaker is 30A, if the backfeed curent is less than 20A, then maybe they think they can get away with it.

If they plan on doing the line side tap then they wouldn't have put the breaker into the panel. It's either one or the other, right? Maybe line side tap is allowed by your local code, so they're going to try the panel feed first as plan A and save the line side tap for plan B if the inspection doesn't pass?

[wanabefree]

Your new solar electric system will need at least two open slots in the breaker panel for the solar feed. As a general rule, the main breaker needs to be 200 amps or larger. If your main breaker panel is 100 amps or less, has fuses instead of breakers, and is in generally in poor condition; you may need a main panel upgrade as part of you solar installation. Your solar installer will make this recommendation if needed.

Not sure if it was clear but this is what the solar installer/engineer is proposing for approval to the city. My panel is in good working order and they will replace two full size breakers with half size to make room for one new 30amp 240v breaker. My main breaker is 100 amp but it is unclear if the buss is the same or not as there is no tags of markings on it I can find. I am inclined to think they are assuming it is a 125amp bus thus with a 100 amp main using the 12% rule they could theoretically put up to a 50 amp solar service feed breaker. They are showing a new 30amp solar service breaker. My concern is how would or could they determine my actual buss panel rating if it is not marked but for having a removable 100 amp main breaker.
I suppose if they submitted it this way and it was not to code the code inspector would catch it and not approve the permit.

They could also I believe use a line side tap if allowed by code.
Oh This is in Moreno Valley, Ca. SCE area if it makes a difference.

[silversaver]

Your new solar electric system will need at least two open slots in the breaker panel for the solar feed. As a general rule, the main breaker needs to be 200 amps or larger. If your main breaker panel is 100 amps or less, has fuses instead of breakers, and is in generally in poor condition; you may need a main panel upgrade as part of you solar installation. Your solar installer will make this recommendation if needed.

[wanabefree]

I am looking over some electrical plans for my proposed solar install. The basic system is 5.75kw using 23 250watt panels and enphase 215 micrconverters. nothing out of line there so far but here is the kicker. I only have a 100 amp service panel and I was original told i would need a electrical panel upgrade to go bigger than about 4k in solar do to the 120% app restriction. (only allowed a 20 amp solar input breaker in a 100amp panel). Well the plans call for the system to be wired with 17 panels in one string and the 6 additional in a separate string. Then they would go to a 125amp combiner panel with one 20 amp breaker and another 15amp bridged to combine the outputs then connected to a 60amp lock able shut off switch. OK so far but then tied into the 100amp service panel via a 30 amp 240v new breaker. To me this seems to be not per code unless they are of the belief that my 100 amp service panel has a 125 amp buss bar. There is no markings anywhere I can find anywhere in or on the panel. The home was built in 1979 and the meter panel and service panel are side by side. I do know that the service to the meter is 200amp rated per But my service panel has a 100 amp breaker that is removable not fused in like some so it is possible the panel buss is rated higher than the 100amp main breaker ?
I am wondering if perhaps they are actually going to use a line side tap but did not show it but then again why would they put a 30 amp solar feed breaker in a 100amp service panel unless they know something I don't or are hoping to get a pass from the building inspector.
I did ask the salesperson about this and he assured me that there engineers no the local codes and would not submit something that is not acceptable and even if the city rejected it they would put what ever the city requires in at no additional cost to me.

Any comments welcome, Dave