I have used them for AC disconnects, but on one restaurant call I got the "deer in the headlights" look when I discovered one of these in a QO panel on a toaster circuit I was working on, I got real lucky, as the problem was the wires burned off the receptacle, when the toaster shorted out, after looking at other breakers in all 4 of the panels for this restaurant, I found 4 more, I showed them to the owner, and he said the electrician who wired the place put them in, after I told him this was just like putting a penny behind a fuse, he had me change them, with no questions.
What I could not believe is UL allowed these to be made, without some kind of way to prevent them from being used in a regular breaker panel, like the CTL tandem breakers.
most dangerous breaker I have ever seen, I can see the little yellow warning sticker not lasting too long as it is just paper, and I know many DYS would just treat the missing amperage on the handle as "it got rubbed off" as it does on many regular breakers, so I can see where these could find there way into a panel by a home owner or DYS,
But the above there was no excuse as both the warning label was on them, and the handle was not marked for the amperage, and the switch was in like new condition.
