I had a quad breaker that went bad. It had 30A outer pair for the dryer and 20A inner pair for my well pump. Both pairs were tied together so you could turn them on or off together - the mechanism tying them together was identical to the ones used on these Eaton's BQ220230 and BQC220230
After doing a ton of reading online I still have 3 specific questions:
1) I've read that these handles are for convenience (so you can turn them both on or off at the same time), and that they do NOT make the breaker in to a common trip breaker (i.e. even with the handles you can still have one side of a pair trip without causing the other to trip). I did see a thread here though, indicating that someone should add these handles to create a common trip. Is this correct? The handles tying each pair together do, or do not create a common trip?
2) The breaker I'm replacing was labeled independent trip, and I see common trip models are available (the BQC varient mentioned above). Why wouldn't I want common trip? The failure I had was only one of the dryer breakers tripping (this was sort of ok because the dryer would work, it just wouldn't get hot). If this happened to my pump circuit though, wouldn't running it at 120v damage it? Is there any reason I don't understand that would make me want to use independent trip instead of common trip?
3) Last, I just wanted to confirm that for the BQC common trip mentioned above. The 'common' only applies to the other side of the same pair, and not to the other pair. I.e. if the top trips (dryer) it will also trip the bottom (dryer), but not trip the two centers (pump).