A/C receptacle- is it safe ?

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Old 05-22-16, 06:28 AM
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A/C receptacle- is it safe ?

Okay so I have been looking for a new air conditioner, and they all seem to have 230V 30amp plugs, with two horizontal prongs and one grounding prong. The trouble is I have a 250V 20amp outlet, and it looks like it will accept a 230V 30amp plug but I don't want to buy a new air conditioner, install it, then have it go kapput because of the volts or amps. I'm not sure it is safe. So would it be safe to plug a 230V 30amp style plug into a 250V 20amp outlet?
 
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Old 05-22-16, 06:35 AM
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I seriously doubt you will be able to plug a 30 A plug into a 20 A receptacle,just the physical size should prove that,post a pic of the receptacle you have.
 
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Old 05-22-16, 07:08 AM
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There are no 230 volt receptacles or plugs. You need a 250 volt receptacle and the 20 ampere plug will not fit a 30 ampere receptacle nor will a 30 ampere plug fit a 20 ampere receptacle.

Look at this chart to determine exactly what you have. http://www.generatorjoe.net/html/web.../nemaspecs.gif

If you have a 30 ampere circuit you MAY change the receptacle and the circuit breaker to allow use of the 20 ampere appliance. It is doubtful that the proper wiring is installed to change upwards to a 30 ampere circuit from an existing 20 ampere circuit.
 
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Old 05-22-16, 09:50 AM
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If the air conditioner has a 30 amp plug then it is likely to draw more than 20 amps at least some of the time. There is a good chance you will trip the 20 amp breaker. The plug implies the amps rating of the circuit you need.

Plugs have different size prongs and different prong arrangements to prevent improper mixing of amperage ratings.
 
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Old 05-22-16, 06:45 PM
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Receptacles use a different voltage rating. A device labeled 250 volts can be used up to that voltage.
 
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Old 05-23-16, 07:30 AM
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okay so this is the outlet type I have, when I looked it up they said it was a 250V 20 amp outlet.
http://i.imgur.com/8qhHaoJ.jpg

this is the emblem I keep seeing on the Air conditioner units saying 230V 30Amp.
http://i.imgur.com/A85wm57.png

I have not actually seen the plug for the Air Conditioners, only this emblem. When I asked elsewhere I got mixed answers. One guy said he was running his machine perfectly using this set up (says the machine actually only draws a max of 15amps) (his was set up using an appliance cable like this one http://i.imgur.com/1yUUecz.jpg ), others say that it wouldn't work too many volts going to the machine would damage it, others say pay an electrician to replace the outlet because it wouldn't be getting the amps it needs. So what should I do?
 
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Old 05-23-16, 08:16 AM
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his was set up using an appliance cable
That is an extension cord. Extension cords are for temporary use.

Single family residences have a nominal voltage of 240. The 230 volts is just the mid range of the voltage the A/C works on. 250 is just the maximum voltage the receptacle can used for. It is meaningless for your purpose because any receptacle will handle the voltage of its configuration.

Most 240 volt A/C are 20 amps but the one you are looking at may be heat and cool. That means it has an electric heater which uses a lot of amps built in.

Simple answer here is if your plug on the A/C doesn't fit the receptacle you have then something needs to be changed. If the manufacturer uses a plug for 30 amp and recommends a 30 amp circuit then that is what you must use. (The NEC requires you to follow the manufacturer's instructions.) A 20 amp circuit and receptacle can't be used. The wire is usually too small for you to just swap out breaker and receptacle. You will need a new circuit.
 

Last edited by ray2047; 05-23-16 at 03:55 PM.
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Old 05-23-16, 01:31 PM
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The receptacle image you show will accept either a 15 ampere or 20 ampere 240 volt (nominal voltage) plug. A 30 ampere plug/receptacle will be physically larger than the lower-rated versions. If the box the A/C unit comes in specifies a 30 ampere circuit then you are out of luck.

What is the BTU rating on this unit? A 30 ampere, 240 volt A/C is a mighty big window (or through-the-wall) air conditioner. Depending on where you mount this thing it could be WAY oversized and that will cause many problems in addition to the electrical problem.
 
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Old 05-23-16, 03:20 PM
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As others said already, you cannot plug 30A A/C on 20A outlet. 30A plug is larger and spacing is different.
Your best way out of this is by purchasing 20A A/C unless your existing wiring is 10AWG. If it is you can change breaker and outlet to 30A, but I highly doubt that.

That being said, you may still be able to use your 30A A/C by changing plug to 20A.
Does your A/C also act as a heater? Most 30A units I have seen are all A/C, Heatpump units with emergency heat. Checking the specification of those A/C, it only goes over 20A when the emergency heat kicks in. The emergency heat is just a set of electric coil heaters.
If you can disable this emergency heat, your A/C and heatpump will work fine. Most have someway to disable it. Switches, jumpers, etc.. However, it won't produce much heat in cold winter.

Also, do this at YOUR OWN RISK. This probably will void warranty for your A/C.
 
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Old 05-24-16, 03:33 AM
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Thank you all for your help. I can't seem to find a AC unit that has the type of plug I need exactly the one horizontal/one virticle/one grounding prongs. I need one that will work with my outlet and it seems like all the ones I find need the 230V 30amp, regardless of whether it has heat or not. I need an AC with at least 15000 BTUs to cool the space properly, it is a Through the wall situation. I have a large opening in my wall (currently filled with a non-working AC). Someone had put a window unit in the wall, and now I can't seem to find an AC that will work without spending more money to get an electrician out here to fix it.
 
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Old 05-24-16, 04:31 AM
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The picture you linked to as representative of YOUR receptacle was a combination 15 or 20 ampere 240 volt receptacle. It should be on a 20 ampere, two-pole circuit breaker circuit. You can use EITHER a 15 ampere OR a 20 ampere rated air conditioner with this receptacle.

A 15,000 BTU/hour air conditioner set up for 240 volts would use about 5 to 8 amperes when running, a bit more upon starting.

Doing a few Internet searches (Google is your friend) I can find several window units as well as through-the-wall units that MIGHT fit your needs, all with either NEMA 6-15 or 6-20 plugs. You do NOT need either an electrician or a 30 ampere circuit.

Here is but one site that has a fairly good search for window (or sleeve) size as well as power requirements and BTU rating. https://www.ajmadison.com/air-condit...r-conditioners

(I have absolutely no connection to AJ Madison, never had any dealings with them.)
 
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Old 05-24-16, 04:55 AM
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It only took me a couple of minuets on Google to find 18,000 BTU 20 amp window A/C with heat so I'm really not sure why you are only finding 30 amp ones.

LG Electronics 18,000 BTU 230/208V Window Air Conditioner with Cool, Heat, and Remote-LW1816HR - The Home Depot

LG Electronics 18,000 BTU 230/208-Volt Window Air Conditioner with Cool, Heat and Remote-LW1815HR - The Home Depot

Note window units have side vents that may be blocked by the wall and can't be used if that is the case with out modification of the wall opening. The old sleeve would definitely have to be removed. If they didn't that could have caused the window unit you say they installed to fail..

My point here though is even A/Cs larger than what you want only use 20 amps. I can't say if you could make a window unit work. (But I could. ) Post some links to the ones you found that required a 30 amp receptacle and we will take a look.

Here is a 14500 BTU through the wall and it uses about 7 amps so would even work on a 15 amp circuit.. http://www.abt.com/product/90356/Fri...r-WE15D33.html

Final note there are ways to make a window A/C work in even a thick wall if your interested. Or running a new circuit can be a DIY job we can walk you through.
 
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Old 05-24-16, 06:05 PM
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all the ones I find need the 230V 30amp, regardless of whether it has heat or not.
If it requires 30A, it has to have heat function. A/C doesn't require that much current.
Even the whole house central A/C only requires 30A.

What are the detentions of existing unit? If you are planning on using existing sleeve, detentions has to be exact and it can be hard to find the exact replacement unless it is PTAC (Packaged Terminal Air Conditioners) unit which have standardized dementions.
 
 

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