My house built 1943, had 2 next to the kitchen sink, untill the early '70s,and pulled out 2 more about 1980 from its evil twin. BTW, they were in great shape even then with the exception of a lot of paint on them.
#152932 - 03/08/0608:52 PMRe: SqD type MO 2-breaker panel
Had to replace one of those not to long ago, as one of the breakers would no longer re-set. It was mounted in a residential kitchen, recessed into a brick wall, and fed through pipe. As you may have guessed, replacement breakers are as rare as hens' teeth.
With this type of enclosure there are no buss bars; the breakers are wired direct, and mounted to the faceplate. Square D does, however, make a "feed-thru" type breaker, with clips that allowed me to mount it to a new fsceplate that I made.
Took a lot of time, and cost the customer (maybe) $150 for replacing a breaker....but there really wasn't much of an alternative.
#152933 - 03/08/0610:53 PMRe: SqD type MO 2-breaker panel
Money well spent! Those are nice little boxes. I have a couple of those guys in my collection, too. I also have a Westinghouse-brand MO box - has one 15a and one 20a. The cover and the box itself is made of a VERY lightweight aluminum. The actual breaker unit probably weighs more than the box .
#152934 - 03/08/0611:14 PMRe: SqD type MO 2-breaker panel
I worked on a Refrigeration unit from out of the Dark Ages that had one of these units on it. It was running a chiller on a chicken farm. Guy that ran the place had his own 11kV/120/240 service. Imported all the gear from the US. You can't put a man down for wanting to bring his own stuff with him. Must have cost a fortune to rewire the place and set the place up. But the wiring confused me somewhat (this was before I was ever a member here). He was happy and I meggered the whole place and not a problem at all. Spare parts (if ever needed) could be a problem though.
#152935 - 03/09/0612:37 PMRe: SqD type MO 2-breaker panel