Interesting topic came up the other day at a commercial inspection with older Square D OCPD’s designed for 2 conductors.
While I had a panel open, there happened to be an electrician there at same time looking at panel at same time as me.
While looking in the panel, we both noticed a few breakers in the panel that 2 conductors, he pointed out he will be writing up to trace and service along with other defects in there, as there were.
I guess he thought I’d say something, he remarked that these types of breakers create a lot of confusion and that the breakers are designed for 2 conductors not 2 circuits, and based on the other sloppy work they were just looking for a shortcut. He said that property inspectors are correct in not making an issue out of it, but most don’t understand the difference.
Interesting point… 2 conductors vs 2 circuits.