Add your new circuit breaker. In my case, it is a new 20 amp breaker. Don’t forget to cut the main breaker!
Add the junction box and run NM cable from the circuit breaker to the new junction box. I used NM 12-2 w/ ground.
For an in-wall circuit breaker panel, I had to cut the dry wall above the panel in order to make it easier to run the cable down from the junction box.
Run 1/2″ steel tubing conduit along with NM cable. Use couplers, 90 degree bends, and clamps.
And run it all the way to your new outlet.
After twisting up the wiring in your junction box, close it up and label it.
Finish up the wiring on the outlet. I used a 20 amp GFCI outlet.