I have 3 multi-wire branch circuits. And two of the 3 set of MWBCs were each put on same phase. An oerloaded neutral has occurred on one MWBC. (It was actually the case of oxidation, not overload, resulting in a smoldered switch box, but the glaring issue of overloaded neutral remains).
It has been cleaned up, but not powered up nor box-packed yet. I have to reposition breaker feeds to ensure that dual-pole having different phases (240VAC on both red/black hots of each MWBC legs) truly occurred.
Much time was spent reidentifying the matching pairs, matching 3 red wires to their corresponding 3 (out of 14 black wires at the panel. They entail popping many coverplates and identifying red wires. Whole house electrical plan was drawn.
Re-paneling is not yet an option yet, but remains a long-term goal (we are getting a swimming pool).
Now it comes the time to reshuffle MWBC wires around at the panel so that each MWBC red/black can be resleeved using hand-noted leftover Romex covering. And to pair them up to a switch being next to each other, but using different phases in order to achieve this true 0VAC neutral (and not the double-amped overloaded neutral like I experienced when fed with same-phase).
A double-pole (that tosses both side of one MWBC off at the same time) is the safety goal here and focus of this question.
What I am unclear on is can I position a double-pole handle-tied switch to span over different phases, using a GE Spacesaver breaker?
Assuming slot 10 is fed by phase A. And slot 12 is phase B.
Perhaps a GE THQP double-pole (handle-tied) 15A and strategically insert it to span across slot 10 and 12 for both-phase coverage for just one MWBC leg? Was looking at simplybreakers.com/products/thqp215 If so, this panel could support up to 3 MWBCs on one side. And gain benefit of electrician safety when turning one MWBC leg/dual-feed to off position.
Or is this CTL meaning to have some kind of guide/notch/peg that may prohibit such spanning of phases by such a dual-pole breaker?