I bought an air conditioner that has a 15a 240 vac plug (NEMA 6-15, I believe - 2 horizontal prongs above the ground) but my air conditioner wall outlet is a 20a 125 vac (NEMA 5-20, I believe - one vertical prong and one that looks like a sideways T above the ground). I have also ascertained that this outlet has its own circuit at the breaker box. I guess I am just curious how big of a procedure it would be to get the outlet changed, as I live in a big apartment building and am hoping it would not involve anything outside of my own apartment - and also that it is cost effective vs. just selling the air conditioner at a loss and buying a different one.
It depends. Either the A/C unit requires both 110 and 220 VAC (rms) or just 220 VAC. If it's a 220 VAC 3 prong plug, in general it only requires 220 VAC (no neutral/return) and a ground. If that's the case, simply remove the white wire for that circuit from the grounding bar and install it into the breaker directly below the breaker for its black wire then wire up the receptacle. If that unit is old (no ground; both 220 VAC and 110 VAC) you CAN use the ground wire of the 12-2G as a neutral/return. It's not code, but it works. I've done it before. Hopefully the first example is your deal. If it's the second, do everything I just said, just realize that the equipment has no ground. Give me some more information. -----------EDIT------------ Hmm. From all the thumbs down, you'd think that I was wrong. I'm not. You also don't need a double pole breaker. It would be nice, but it's unnecessary. Under my plan, you would use already existing breakers and have to throw both of them to kill the circuit. It's not exactly code, but there are no real safety problems if you label it correctly.
It will involve swapping a double-pole breaker for the single-pole breaker you have now plus changing the outlet. The 15A 240v outlet has no common wire so you can re-use the wires you already have (hot/neutral becomes hot/hot). Unless you're out of space in the panel it should be a pretty straightforward job.
I'm not an expert but it's not just a matter of changing the outlet. You'll need a different circuit break in the breaker box and the wire has to be rated at that voltage and current. It might be but probably isn't so the wire would have to be replaced as well. This means opening up the drywall all the way back to the breaker box then replace the outlet and drywall. I'm pretty sure the landlord would not approve. If possible I would take the unit back. If not, take the loss and get the correct one.
I'm afraid that merely changing the receptacle to suit the configuration of the AC plug isn't going to solve your problem.The fact is you need 240 volts but the wiring is only delivering 120 volts. The other end of that wiring is connected to a single pole breaker of 120 volts. a 230 volt breaker needs 2 poles in order to supply the higher voltage. Now- If this was your house, you could do as you pleased with the electrical circuit to suit you. But I'm pretty sure if you tampered with the wiring in that apartment it would be illegal.I think the best thing to do is trade it for a new one of the correct voltage.
Jeff D is correct. If you have a dedicated circuit in the unit now, and you have the physical space for the additional breaker, then it's maybe a 1 hour job for a service electrician to make the change. When you contact the electrician, tell them the size of the breaker needed and the voltage, also brand and style/model of the panel. Square D is a common brand of good to high quality, that may be a QO, QOB, MO, or HOM, different brands have different model and abbreviations. This information in advance can save several hours of service time.
