Originally I was wondering if the Mains 225A max. from the label inside the panel box was the rating of the bus bar. Since it seems there are/can be addition labels on the panel interior itself (the black plastic holding the breakers and bus bars), I wasn't sure if I'd have to pull the meter and main breaker to confirm.
Researching Schneider's website, I noted that for 42-space single phase interiors in QO plug-on neutral style there appear currently to only be 225A bus bar ratings available for purchase. While that seems to be a pretty good indicator, I still wanted to confirm a bit more if possible.
I contacted Schneider's technical support to ask if they could confirm that they've only ever sold 225A bus bar interiors for the style/size/phase of my box. The representative wasn't able to do that. But representative proceeded to say in our chat:
But if you look at the wiring diagram label (should be on the inside of the box on the right or left endwall), it will have a rating along the lines of "Mains max" or somewhere along those lines. That will give you the rating of the bus. It is most likely 225 A, but I can't say for sure without knowing the actual part number
So it appears that you can determine the bus bar rating from the panel box interior label without needing to find a label on the breaker holding interior itself.
While I'd normally recommend having your standby loads on a subpanel...
My normal recommendation to folks who want a backup generator, whether portable or permanent, is to move their standby loads into a subpanel. This is how the "big boys" do it, as it provides a built-in level of protection against generator overload from large/unnecessary loads (such as an electric range in a house, or a large motor load in a hospital), and also can be used with equipment suitable for a bonded neutral generator, which is important as portable generator sets generally come from the factory with their neutrals bonded so that they can meet OSHA specs for jobsite use.
If you were to take this up and have the standby loads on a subpanel, then this problem would be a nonissue as you could simply have an extra branch circuit run to the subpanel for the purpose of having a "utility on" pilot light fitted there.
However, there is a way out of your situation while maintaining the use of a CSED
The good news is that thanks to the use of line-side taps on solar systems, there are a couple of possible solutions to your puzzle of how to get that single utility circuit in a whole-house interlock setup. While your proposal #2 with tap lugs on a 200A meter base can be made to work using a Milbank lever bypass socket and a set of Milbank K5022-INT tap lugs, the coming 2020 NEC exterior disconnect requirements make a CSED (meter main) a simpler choice for this application. Furthermore, thanks to the aforementioned line-side solar tap stuff, Square-D makes a lever bypass meter main that has support for a line-side tap lug kit, namely the RC816F200SLS. While something you'll have to special-order from a supply house, you can fit it with a SR69064A lug kit that lets you make a line-side tap off the busses to the main breaker without voiding the UL listing.
With this out of the way, we can use a 1" nipple from the bottom right of the meter-main to the bottom-left of a 30A fused A/C disconnect, with a pair of 10AWG copper THHN wires for hots inside the nipple, and bonding locknuts with 8AWG copper ground jumpers on both ends as this is service entrance wiring. In this disconnect, we can fit a pair of 15A or less cartridge fuses to provide overcurrent protection for the alarm circuit; from there, you can make your indicator as sophisticated as you wish.
As to that alarm...
While there are a variety of solutions to the alarm problem, the simplest possible alarm one can implement that won't whine at you for the entire time the power is on consists of an NEMA 4X enclosed SPDT relay with a 240VAC coil, an IP65 rated 240VAC illuminated SPST 22mm pushbutton, and an optional IP65 rated 240VAC audible alarm device (buzzer) that fits a 22mm (1/2" trade size) KO. In particular, a Functional Devices RIBH1C-N4 can be used for the relay, an IDEC HW1L-M1F22QD-G-240V (or -R, or -Y, whatever color floats your boat) works for the illuminated button, and an Auer Signal M22-30K-240VB will serve as the buzzer in this application. These parts are all UL listed as industrial control devices, so there are no Code issues with using them in this application, and 22mm devices fit into 1/2" trade size (7/8" actual size) knockouts, which your average A/C disconnect sports plenty of.
Hooking this up goes as follows, using 14AWG THHN and ordinary wirenuts:
- First, the various devices get mounted. The relay's nipple goes in the leftmost bottom knockout on the disconnect, while the alarm goes in the rightmost bottom knockout if used, and the right-side knockout gets used for the button.
- Then, we start wiring things up with the pigtails from the load side of the disconnect. One of these pigtails is wirenutted to the yellow common wire on the RIB and a pigtail to one of the NO terminals on the switch, while the other LOAD pigtail from the disconnect is nutted to the white/yellow coil wire on the RIB, a pigtail to one of the light terminals on the switch, and a pigtail to one of the terminals on the buzzer if the audible alarm is used.
- We then move onto the other coil wires on the RIB: the white/blue coil wire gets capped off as it's not used here, while the white/brown coil wire gets nutted to a pigtail from the other NO terminal on the switch and the orange NO wire on the RIB.
- Finally, the blue NC wire on the RIB gets nutted to pigtails from the remaining light terminal on the switch and the remaining terminal on the buzzer, if present. Any remote alarm indicators can be connected in parallel with the light and audible alarm, as well. Just keep in mind that this remote indication would be a 240VAC, Class 1 control circuit, so you'll have to run it using 14/2 NM with the ground wire in the NM cable connected to the grounding block on the AC disconnect box.
The basic theory behind this is that we are using the relay as an inverse stick relay, allowing it to store the "alarm reset" state. Starting with the power off, the alarm signal is connected to incoming power via the NC (normally closed) contact on the relay, allowing the alarm to turn on when power returns. In order to reset the alarm, pushing the button applies power to the relay coil, causing the relay to energize its NO (normally open) contact instead, which provides power to the relay coil after the button is released, and thus "sticks" it in the "alarm reset" state until power is removed from the circuit again.
Best Answer
You can't cross brands with any breaker
Yes, they seem to fit, and you think "Gosh, the companies got together and made breakers standardized" Well, they didn't. They were actually maneuvering to avoid each other's patents, and as a result every bus design is different, and the clips will not mate to the stabs properly - they'll make edge or corner contact and overheat.
So put that "swapping breaker brands" idea right out of your head. It is a dead letter.
With that said, I can tell you QO has a totally unique bus shape that will not interchange with anything else - not even close.
Now, there is one exception. UL has a way to certify one brand's breaker for a competitor's panel. This is called "UL-Classified". Note that manufacturers make a completely different line of breaker specifically for competitor panels. Their regular breakers are not cross-Classified for competitor panels, so an Eaton BR is not allowed in a Siemens panel, even though Eaton CL type is.
Eaton and Siemens both make UL-Classified breakers for QO panels, but unfortunately that does not solve your problem.
Square D does make 225A-bussed panels.
The key is don't confuse "main breaker" with "bus rating". Getting 70A of solar on a consumer panel needs exactly a >=225A bus rating but exactly a 200A main breaker. Unfortunately, QO's catalog numbers suffer from this very confusion.
Sidestep the problem with a "Solar-Ready" meter-main
Solar-Ready meter-mains have a neat trick. Above the main breaker, on the supply side, they either provide a direct tap or a second breaker.
By putting the solar power on the supply side of the main breaker, this entirely moots the 120% rule and you are free to run up to 200A of solar.
Noting that you are looking for a combo meter+main+all breakers (why??? they're awful) panel, those are sold in "Solar Ready" versions by someone or another. That goes far to explain why Square D will never make a combo panel with oversize busing, the only use for that is solar, and Solar Ready panels do a better job of filling that need.
Make your own Mega-Solar-Ready panel
A "Ranch Panel" is a variation on combo panel. It has meter + main + only 4-8 breaker spaces + thru lugs intended to go to a master panel elsewhere which will have all your breakers. "Elsewhere" can be 1 inch away.
In the 4-8 breaker spaces you install all your solar breakers - up to 200A of solar!
Off the "Thru Lugs" you go to a Regular Old main breaker panel with 200A busing. All your regular loads go there. Is the main breaker redundant? Not at all. It solves the 120% problem for both panels! This panel can't pull more than 200A obviously, but neither can the Ranch Panel. Crunch the numbers and see.
Since the Ranch Panel only serves solar, it doesn't really need to be QO type.
Abuse a 400A meter-main to same effect
With power company permission, install a 400A meter-main. These have two 200A breakers, with one being an optional add-on, allowing you to choose its size. The optional breaker you send to your solar. The other 200A breaker serves a Plain Old 200A main-lug panel where you put your normal loads. This panel can be anywhere, including 1" away from the meter-main.
They also make 400A ranch panels, which is simply a 200A ranch panel with an extra site for another optional 100-200A main breaker. This breaker could be used to feed the solar, or, you could flip the script and use the "mini-panel" for solar, and have the solo breaker feed a plain old main-lug panel for your loads. Just another way of doing the same thing.
Combo panels, generally, are anti-awesome
I would steer you away from a "combo panel". The problem is down the road. If you outgrow the panel or it becomes damaged or you run into obsolescence... now what? Your only option is a huge production: replace the whole thing, which requires the power company come and disconnect your service wires, permits, inspections, whole nine yards. With another costly $1000 combo panel, instead of simple cheap separates.
Whereas the more you have separates, the more liberty you have to simply change out the one thing that is not working for you. Classically, people would run out of "breaker spaces", and that's particularly acute with all-in-ones, which give shamefully few breaker spaces to limit vertical size. Many are advertised as "16/32" meaning 16 spaces 32 circuits, but guess what - that "32 circuit" number is malarkey, since most circuits need full-size breakers now. Also, we're expecting a "smart grid" in the next 10 years - panels like Span are already doing it, and we expect that to retrofittable into existing panels. But the tech may not physically fit in QO's smaller package size.
All that to say, I'd rather see you get a meter or meter-main, and a plain old 40-space master panel for your breakers, than try to reduce box count by 1 with an all-in-one.
Remember your solar needs to have Rapid Disconnect in any case, and with microinverters, any of my suggestions above will handle that for you without an additional box.