I came across a panel that has been serviced by at least six people, some of them Gen. contractors, some even less qualified. The panel has a lot of mysteries because of repeated remodels and renovations to the house.

I'd like to be able to recognize the usual and legal uses of tying breaker handles together. But I would also like to be able to spot "cheats" if any exist.

Multi-wire circuits come to mind, when one duplex has both circuits.

On an unrelated note. I am pretty tired of coming across tiny 10/20 sub-panels maxed out with half-size dual breakers.

Handle ties must be "approved" and not necassarily listed. The only person that can approve is the AHJ "see definition". A 16 penny nail might be approved in some necks of the woods, but it is not in mine.

I have yet to need to use a handle tie and it must be because I'm doing a lot of vanilla work.

(except for crazy house)

When do you use the tie handles?

I have done this in a jam but only temp. You will always have one two pole in the truck and the tie bar pops off easy enough. Then just snap it back on when you install the correct breaker.