AC on 20 AMP Outlet?

Smiletwice · 07-04-2018, 11:01 PM

I've seen a number of threads related to running AC in the trailer while it's plugged in to a standard outlet while parked in the driveway. There are very strong, conflicting opinions about this. My specific question is this.....if nothing else is running, and the heavy 30 amp power cord runs all the way from the trailer to the outlet, where it drops down via pigtail adapter and plugs in to a 15 amp outlet, am I safe running the AC? I also have one 20 amp outlet available on a dedicated circuit in the garage. Would that make a difference? If it just blows the breaker in the house, I guess I know it's not going to work. I'm more concerned about the possibility of damaging the AC unit or starting a fire from heat buildup. Appreciate any insight.

Blackrock · 07-04-2018, 11:18 PM

I've done it a gotten away with it. A lot depends on outside temps and how hard the A/C has to work.

fella10 · 07-05-2018, 12:17 AM

Our ac is the 13.5 and it works just fine doing that at home, no problem at all, ... plus, I've modified my ac wiring so that with a flip of a toggle switch, I can power the ac with a #12 extension cord, ... I did that to take the ac amp load off of the trailer 30A system, ... I always use the extension cord setup when possible, ... but there are cg with 30A only service(no 20A or 50A outlets on the power pole), we've been to at least two like that, ... in those cases, with a flip of the switch, the ac is back on the trailer 30A system(just like it came from the factory) and we're still good to go and gonna stay cool, ...

andymil · 07-05-2018, 12:40 AM

If you had an EMS, you would know what the voltage is dropping to when the A/C is on.

valleyduo · 07-05-2018, 01:29 AM

If all you will be running is ac and some lighting perhaps, the 20 amp should suffice. I agree with Andymil to check your voltage with an ems. I've done this myself at home for cleaning day or what have you. My voltage dropped to 118 which is not going to do any harm. I wouldn't recommend the 15 amp outlet.

cavie · 07-05-2018, 04:54 AM

Have a look at the breakers in your rig. You will find a 20 amp breaker for the AC. No problem at all running on a 20 amp at home with your 30 amp cord OR a 12 ga extension cord with adaptors. Just keep it as short as possible. A 1350 unit draws 11.25 amps. A 1500 draws 12.5 amps. You will do no damage to anything on a 20 amp circuit. If your 20 amp circuit is on a GFI, trip or turn of the GFI in your camper. 2 GFI's don't play nice together. Your AC may not like it either. If you can plug it into a non-GFI outlet.

CedarCreekWoody · 07-05-2018, 05:23 AM

I often run mine on a 20 amp breaker with no problem. I also use the heavy 10 gauge cord with no significant voltage drop.

Smiletwice · 07-05-2018, 09:07 AM

Quote:

Originally Posted by valleyduo

If all you will be running is ac and some lighting perhaps, the 20 amp should suffice. I agree with Andymil to check your voltage with an ems. I've done this myself at home for cleaning day or what have you. My voltage dropped to 118 which is not going to do any harm. I wouldn't recommend the 15 amp outlet.

When you refer to an Electrical Management System, I assume you are referring to the device that plugs in between the power cord and the pedestal. Unfortunately, I have the one that has surge protection and only checks to make sure the wiring is correct. It does not monitor voltage. Is there another way to check the voltage coming in to the AC? I have a multimeter, just not sure where to check in this situation. Also, can the surge protector be attached directly to the adapter and then in to the 20 amp outlet? Thanks.

jeff64 · 07-05-2018, 09:18 AM

Quick and easy test. Run your hand along the power cord and your extension and pigtail. Getting warm by the plugs? There's your answer!. Look at your cords, anything looking soft or melty on the plastic surrounding the electrodes? Again, there's your answer

CedarCreekWoody · 07-05-2018, 09:19 AM

I have a small night light that displays voltage constantly. I keep it plugged into an outlet in the bathroom. I also have a hardwired Progressive EMS that monitors the electrical supply. The night light came from Amazon, 10 bucks or so.

Smiletwice · 07-05-2018, 01:15 PM

Quote:

Originally Posted by CedarCreekWoody

I have a small night light that displays voltage constantly. I keep it plugged into an outlet in the bathroom. I also have a hardwired Progressive EMS that monitors the electrical supply. The night light came from Amazon, 10 bucks or so.

Thank you! I'm going to get one of the voltage monitors. So if I've got AC running off 15 or 20 amp outlet (through adapter), and the cord isn't heating up, as long as the voltage meter is showing something between about 105-125 volts, I should be okay?

ProfChuck · 07-05-2018, 01:16 PM

It will work for a while on the 20 amp, but, don't let it overheat. Don't use the 15 amp at all. The 20 amp breaker may still trip, so make sure your electric water heater is turned off and anything with a big draw (you can usually get away with a couple lights). I used to use the 20 breaker all the time in storage, but, couldn't turn on anything else. Finally installed the 30 amp (that is what I have on my TT) and everything is fine. May someday have to put in the 50 if I get a 50 amp unit.

HDU · 07-05-2018, 02:00 PM

The rule of thumb with electric motor manufacturers is that incoming line voltage can vary + or - 10%. And that doesn't necessarily mean that the motor will fail when ran outside of this tolerance, it does mean that more than likely the motor will not perform to the ratings that are designated on the name plate, and its life expectancy MAY be compromised if used extensively near or outside of the tolerance spectrum.

120v compressors are powered by electric motors. However, not all electric motors are built to the same standards, but most are. Some have less service factor built into them, and these are less tolerant to fluctuations.

My local utility will not guarantee power at less of a tolerance than + or - 10%, meaning that on my 120 volt system, I could see voltages as low as 108v and as high as 132v, and that would be acceptable to the utility company as sufficient supply voltage. Motor manufacturers make their motors with this fluctuation in mind, otherwise there would be failures and warranty claims on most of their products, much of the time.

So I wouldn't worry as much about your breaker ratings (amperage) as being the weak link, I would worry more about the voltage drop realized in your extension cords and connective equipment. If your utility drops the rated voltage by 10 %, and then your extension cords drop it another 5% or more, you could run into some heat building issues with the motor, and horsepower loss as well... and in turn, possible damage to the air conditioner/compressor especially if used like this over a period of time.

Short answer to your question, I use my air conditioner very often at my home on a 15 amp breaker, never have tripped the breaker and the air conditioner runs just fine, but I use a shore power cord as the connecting device which has large gauge wire. If you have a 20 amp breaker circuit, use that one since it should have a larger diameter wire feeding it than the 15 amp does, hence less voltage drop at the outlet if it is a longer run.

AdamKam · 07-05-2018, 02:06 PM

I have used 20 amp outlet to run a 15,000 AC with a 50' #10 extension for years. The only problem I had, when I first used it the connectors welded together due to being only 15 amp. Make sure you have high quality end plugs if using an extension cord.

Dpelaez · 07-05-2018, 03:17 PM

The a/c will run but 13,500 needs a lot of amps at start up and continues to draw heavily during its operation. Yes the a/c will work but you could damage it with extended use. I easily added a 30 amp breaker and installed an RV type outlet at home . It was easy and I have peace of mind if I ever want to run the a/c while I watch TV or listen to the stereo while parked. I'm good.

markb422 · 07-05-2018, 06:38 PM

Run our AC on a 20 amp circuit that I installed just for the MH all the time on the rv pad next to the garage. The garage is where the house service panel is also. So, the dedicated circuit is only about 5 feet of 12 ga wire from the panel. I also use a plug in digital volt meter. Distance from the panel does matter.

B and B · 07-05-2018, 06:41 PM

Most 2000 watt class generators deliver the same as a 20 amp outlet or less. Try it, look for hot connections.

markb422 · 07-05-2018, 06:58 PM

Most 2000 watt generators are only rated 1750 to 1800 continuous. 1750watt/120volt is less than 15 amps.

garbonz · 07-05-2018, 07:01 PM

Start up surge is the biggest problem, which can be cured by installing a easystart module by Microair. Replaces the start capacitor and gradually starts the compressor so it essentially eliminates the surge that pops breakers. Most AC units draw around 14-16 amp so it can be done WITH a good cord to limit voltage drop.

DavidBo · 07-05-2018, 07:33 PM

Don't forget you can be drawing power without knowing about it! Namely, the converter will be quietly recharging your house battery in the background. If the battery is low that could be a bit of a draw, just something to consider.
I tried running my 15K A/C on household current, it would sometimes work, but on really hot days eventually the breaker in the house would trip. I added a piggyback capacitor, but eventually ran a dedicated 30 amp circuit for more peace of mind.

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