said by iknow:We've tested Sq D breakers that would not trip until they disintegrated. All circuit breakers should be manually exercised ON/OFF on a regular basis. Especially those in harsh environments. said by nunya:
I think they all should be bolt-in. I used to like the SQD bolt in stuff, but they went to plastic retainers on the outer rail. All manufacturers went to plastic, but most slide under (BR style). SQD basically have to be "smashed" on.
maybe they are trying to avoid high resistance stab connections!. if you make the connection really tight, it reduces the possibility of high resistance connections. SQD had really nice breakers, they'd trip very quickly on a short, which was uncommon at one time.