Working on a house I found the main breaker stuck in the closed position. I tried several times but couldn't get it to open. I ordered a new one to replace it, but I was wondering what the cause may be and if there's a remedy (without replacing). And is it possible the breaker can still trip if there's a fault? I'm just curious, because I've never ran across this before. The breaker is a CC2200 now discontinued. The replacement is the CCV2200.