Totally agree with JLH, Smallest breaker is your rating cause its the weak link. Be sure to check for series rated stickers that may change the rating if the are series rated with upstream breakers (not very likely but you should check).Typically the AIC rating is determined from the lowest branch circuit breaker rating.
Well, it depends upon the actual meaning of "vintage". There is a lot of hardware, over half a century old, that is very identifiable to an experienced eye, even without the stickers, that is 10,000 AIC. Too bad its almost impossible to use images right now (the BBCode is still being tuned).I agree with you both, but I am talking about no labels or stickers indicating any application data.
As I recall, the NEC specified minimum KAIC was doubled from 5 to 10 around the 1965 NEC. That's over half a century ago.I don't think a lot attention was given to things like miniature breakers, load centers and gear utilizing edison base fuses until 30-40 years ago.
LATE BREAKING BBCode NEWS: The Forum, as of this morning, is again able to handle JPG photo images. If you can get a JPG snapshot of the panel and circuit breakers in question, and have it as a file (smaller than 2 Megs) on your local hardware, the "Upload Attachments" radio button in the "Write Something" post entry box at the bottom of this thread's page will process it into a thread post. Try making use of our collective "experienced" eyes.Thanks Al
I don't recall reading that regarding panel/Cber ratings....more likely just forgot.
The specific building went up the year I was born...1957. I will have project EC pull a few CBer's to check for any markings.