When I went to add a light switch near my attic access for an existing light with a pull cord, I found that the light was wired to the disconnect box that feeds the air handler. This particular circuit is fed by a 60A breaker in my main panel (I assume it is so large due to the emergency heater if the heat pump is not working).
The light is wired with a 10 gauge cable, but this just seems really wrong to me. I suspect this was put in by the AC guys before we owned it since it was attached to a truss with hex head screws. It also didn't even have a junction box! The fixture was directly attached to the truss with enough clearance to wire it from the back. The terminals were exposed to open air and someone could have have touched a live 60A circuit. These are the same AC guys that cut 3 truss members so I don't have a lot of faith in what they did.
I have fixed the junction box situation, but before I add a switch to this I wanted to confirm that I need to move this to another circuit. Maybe there is another breaker inside the disconnect box that is only 15/20A? I didn't see anything...
This light fixture also has a receptacle built into it. Like this:
Update
I looked a little further into it and the neutral for the light is connected to the ground and it measures 120V at the receptacle. There is what looks like a 2 gauge aluminum coming in and a 6 gauge aluminum going out to the heater/ air handler, plus the 10 gauge copper going to the light/ receptacle. There is no separate 15A for the air handler. Side note, why does the tester show hot/ground reversed for this situation? My pictures don't stay rotated properly on the phone app...