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I'm planning to upgrade my electrical service and am interested in getting a 225 amp main load center. I can only find 200 amp meter sockets, though. The next highest ampacity meter socket I can find is 320 A and it's significantly more expensive than most of the 200 A sockets.
Are there any 225 A meter sockets? If not, what are you supposed to do to meter power going into a 225 A main breaker box?
The reason you're confused is because meter sockets are rated by their continuous ampacity, but panels and breakers are rated by their maximum nominal ampacity; this difference is most clear in Class 320 work, where a 320A continuous meter base is used either with a single 400A or a pair of 200A service disconnects. As a result of this, a typical 200A meter socket is rated for 200A continuous, and thus will have no difficulty with a 225A service, provided your utility recognizes it as a valid service (not all utilities do!).
Since your challenge is spaces moreso than amps, I want to be clear that it is perfectly OK for your panel's bus rating to exceed your service.
The bus rating is simply an absolute limit: if you drive 85, do you want tires rated for 85 or 130 mph? It's a safety margin thing, it's not a "must match exactly" thing.
To put it another way, There is no tie-in between number of spaces and service ampacity. 42 spaces on a 60A service? No problem. 8 spaces on 225A service, I have actually seen that, several times, no kidding. They did not realize the panel was meant to be thru-lugged.
But wait, then, how does provisioning work? By a "provisioning calculation" based on square footage, typical appliances, and some basic math based on how average homes behave ... plus some factors for your exceptional loads. Say you're a master machinist with 20 different machine tools each pulling 30A. How much do you provision: 20 x 30? No--- only 30A -- there is only one of you, so you can only use one tool at a time.
If your actual loads show you can make it in the (100A?) service you currently have, then your only task is to swap that panel.
You can always upgrade the service and meter at a future point.
What do you do about the fact that your beautiful 42-space panel comes with a 225A main breaker? Easy, you buy a "convertible" main-lug panel and fit a 100A main breaker either in the official main location, or simply in a normal breaker spot and backfeed it. Later, when you get bigger service, you fit the 225A main and remove the 100A.
If you're having trouble with panel selection, flee the big-box store and go to a competent electrical supply house. If you have a brand of panel in mind, pick a supply house that is a dealer of that brand.
No. There isn't. but it would seem that 25 additional amps is pretty specific. How did you get there? A class 320 MB is designed to feed 2 200 amp panels. You can't feed a 320 MB into a 200 amp panel. What are your loads and how many do you expect to run at the same time?
EDIT: I don't know what happened here, but I was full of BS when I posted this. It's all wrong! Dang, there are 225 amp panels and you can feed just one panel off a class 320 MB. I'll either delete or edit it later, but wanted to fess up that I was wrong.
