I asked my electrical supplier if they could find a breaker for an old square D XO panel. They were able to find one in California. I had it next day'ed to me. For some reason, I never expected it to come in the original box.
I paid just a few dollars over $100.00. I'm not sure of the exact number, $103, $105? I actually expected to pay more. I've paid quite a bit more for odd ball stuff before.
The company my supplier purchased it from was California Breakers. I know this because my supplier had it drop shipped right to my office and the company enclosed the invoice to my supplier in the box (oops). At least I now know that my supplier doesn't gouge me on the special order stuff:). California Breakers has a web site but no way to search their inventory online.
I'd do all I could to encourage the owner to replace that panel. I have seen a couple of destroyed XO panels. They did get wet and i am sure that was a big contributer to the failures. Part of the breaker insulation is paper. The panels usually have no main so I really hate them as a service entry.
#185954 - 04/07/0905:23 PMRe: Got an old breaker today- for electrical nostalgia
Not too sure how good or reliable they are, but I have seen quite a few Square D and Cutler Hammer XO - style breakers for sale on eBay. Like I say, I'm not sure how great an idea it is to buy something like this on eBay.
Regarding the lack of a main breaker, I bought an old Square D XO panel and breakers on eBay some time back (to add to my collection). The branch breakers were XO, but there was also a 2 pole 70 amp "multibreaker" style main installed. An unusual combination, but in excellent condition.