Wiring question converting 120to 240

Question

Here's my question since it maybe confusing. Correctly there is a 12/2 with a ground running from panel in basement to the second floor AC. The outlet for the AC was wired 120v 20amp. I am going to install a ductless mini split and need 15amp 240v. So what I want to do is change the single pole breaker to a two pole breaker move the neutral to the breaker tape it red and change the outlet to a disconnect. So far I have no issues doing this.

My question or concern is how can I made sure there's no additional outlets/lights Daisy chained before the end of the line before I make it 240v. I obviously checked the normal ways and have turned the breaker off for 3 months and haven't noticed anything not working.

Answer 1

Yeah, sounds legit. Generally since the circuit served the A/C before, it is typical for those to be dedicated circuits and thus homeruns. If there are onward wires, you'll know when you open up the socket.

You can fit a 15A breaker and NEMA 6-15 recep(s). Feel free to use a dual 6-15 so you can just keep the same faceplate.

Or, you can fit a 20A breaker, and fit either a) any number of NEMA 6-20 sockets, or b) two or more NEMA 6-15 sockets.

Oh, one more thing. Code requires that a receptacle exist within 6' of any point along walls (following the walls around corners, not straightlining). You must make sure eliminating this 120V socket doesn't make you fall short of minimums. If it doesn't, that's good evidence that the socket was installed specifically for the A/C, and may have even been 240V once upon a time.