You can use the existing wiring if you have at least 14-2 wiring and you aren't changing amperage. You need to shut down the main breaker first, install a double pole 15A breaker in your main breaker box (simple clip in job). Wire the black and white wires to each of the screws on the double breaker. On the plug side, simply wire the black and white to the 2 hot (yellow or darker screws) screws on the plug. Make sure you're all grounded on both ends, bare wire to the metal outlet box plug side, or to a ground screw, and to the green screws in the box. If you aren't sure which screws are for ground in your breaker box, you shouldn't be doing this job. This 240V setup requires no neutral, and is up to code.
Mark your outlet as 240V otherwise you're going to blow stuff up.
Mark your outlet as 240V otherwise you're going to blow stuff up.
