Hello. I am rewiring 240v through the wall a/c. It had 20 amp, 250v round outlet with horizontal slots and a ground hole. The a/c is in the kitchen and saw only occasional use. I am rewiring this because the romex used has a ground wire that is only about 16 ga. thick and the cloth cover (around the rubber jacket) is fraying throughout. The questions:
1. I should have asked first before cutting out the wires, but would you have kept the 16 ga ground? The wire insulation is in good condition.
2. Having heard that 240v now require a neutral, I went to HD to look for same kind of outlet (because of the a/c plug), but I saw only the same outlets – 2 screws and a ground screw. Does the 4 wire rule apply to 20 amp circuits as well? Or does it mean I have to change the a/c plug to 4 prong plug? I would not do this for this a/c. but would you clarify this question?
3. After this a/c, I probably will go to 120v a/c. Are the old name brands still the best choice, or are there names I should look for? I’ll probably need 8000-10,000 btu units that are quietest and reliable. Lennox is in there now. I think it is almost 30 years old, but works fine, but loud.
Thank you in advance.
Replies
You have a couple issues.
First off, the plug that came with the air conditioner is the correct one. This is not the case with kitchen ranges and clothes dryers, which may be sold without a cord & plug - but that's another story.
For the air conditioner, you need two colored wires (usually black and red) and a ground. You are NOT allowed to use the white wire. The new Romex will have a ground wire with it- use it.
Best thing to do is to leave a generous length of white wier in the box, so you can use it later if you want to switch back to 120v.
The reason someone used 240v. was because they wanted a big air conditioner. The size you're looking for pretty much needs 240v..
A better way to do this is to hire an air conditioning contractor to put in what they call a 'mini-split' system. This has a separate condenser set on a pad outside, with the freon lines going to a fan unit that hangs on the wall. It will cost a lot more - probably $3,000 - but will also be a lot quieter and do a much better job.
Why can't you use 14/2 cable (with ground) to wire a NEMA 6-15? (reidentifying the white wire)
14/2?
Well, he needs a ground. I think the cable maker includes the ground in the labeling of Romex.
#14? Well, he did say '20 amps.' The size of unit he describes would certainly need a 20-amp 120v circuit.
Re-mark the neutral wire? While you are, technically, allowed to re-identify the wire in a cable, such as Romex, the marking is supposed to be 'permanent.' The OP is talking about later changing the circuit to 120v. I think he is poorly advised to omit that 'extra wire' at this time.
NEMA 6-15 receptacle? Because that's not the receptacle the plug he describes will fit.
Have you ever seen a 14/2 cable at "HD" that wasn't 14-2/wg? I am not even sure you could get ungrounded NM/b at a supply house.
The receptacle was described as "two horizontal slots" That sounds ike a 6-15 to me. A 6-20 would be a horizontal and a vertical slot
Of course, I've seen cases where the prongs on the power plug have been twisted to fit the socket.
You only need a neutral present if you have a neutral load. Your window shaker does not have a neutral load.
If you are rewiring this I would use #12, simply because if you are going to a 120v unit later, you can use the 20a receptacle and get a big unit.
The mini split idea is not a bad idea tho. I have 2 now, in addition to my central unit. We seldom use the central unit.
You can freeze the bedrooms for sleeping without running the AC in the rest of the house.
Ya to what gfret said. I installed a permantely mounted AC location through the wall in our suite. #12 wire with a two pole breaker allows for any option you want down the road....120V, 240V, whatever.
Thank you all for the answers. I did not know if new 240v a/c's would come with 3 or 4 prong plugs. But that's ended now since if I need another a/c in kitchen, I plan to get 120v a/c. The current a/c is actually Fedder 12000 btu. I got this when the original a/c had to be replaced. I don't know why the original HO got such a big a/c since the kitchen is not that big, and the kitchen gets icy cold with this unit. I rewired with 12-2.
NEMA 6-15 certainly does have two horizontal slots - both going the 'wrong' way .... but, again, the OP is waffling whether he wants 120v or 240v. The 6-15 is a 240v. pattern.
It's a quirk of the industry that with Romex -even at Home Depot - they include the ground with the wire count. Oddly enough, it is MC - the metal covered cable- where they do not count the insulated ground wire in the count.
Don't feel bad; I'm always getting confused.
I believe Leviton still sells a duplex receptacle that has both a 240v and a 120v receptacle on it. To use it, you need that neutral wire present.
The trouble with any cable is that once it's in the wall, you're stuck with it. You can't change or add wires later. That's why I was running neutrals through switch boxes long before the NEC ever required the practice.
I still advise the guy to run a cable that has a red wire in it. It's his choice; he can either spend a few pennies now, or many dollars later.
It's a quirk of the industry that with Romex -even at Home Depot - they include the ground with the wire count.
????? What ?????
Generally, romex is speced as, eg, "14-2 w/g", where the "w/g" indicates "with ground". The ground is NOT included in the wire count.