Set me straight...AC on 120/20amp outlet.

[DinTulsa]

So I've been reading a number of threads talking about running the RV AC on 15/20 amp outlets. So I looked at my breakers and they are all 20 for the house, I currently run a 50ft 10ga extension cord to my rv cord for shore power. My main unit is a 15,000 btu dometic AC. I tried it out this morning just to see and it ran fine and cooled for the 5 minutes I ran it.

My concern is that a 110/20 amp outlet will damage the unit? Is that the case? The only time it would run would be when I'm loading the rv in the afternoon before we leave. When it's 100 degrees outside being 80 in the rv would be nice. I would switch the fridge to propane during that time to reduce the electrical draw on the system.


Any info would be appreciated.

[TurnThePage]

Good points here. My problem is likely a 15 amp outlet (even though it's on a 20 amp breaker) that's heating up over time.

To the OP, the kill-a-watt recommendation really should have been more generic in nature. There's plenty of meters that will do the trick. Here's a typical one that will give you a continuous readout.

[myredracer]

I would read the manufacturer's electrical info. The issue is not only voltage while running, it is voltage on initial startup. This Coleman info. (see page 7) states a min. of #12 ga. and that for lengths greater than 50' you should use #10 gauge. This would include the shore power cord plus length of run from the recept. to the house panel.

Starting inrush current (locked rotor amps) is around 5-6 times running current and for the above Coleman 15K unit, is 63 amps which can cause a high momentary voltage drop. Running current is listed at 15.3 amps and breaker just for the AC is 20 amps, and you may need to keep all other loads to a min.

Ensuring the voltage is good is the key and I would use a permanently mounted LED voltmeter inside to keep an eye on it.

[joshuajim]

Be aware, while your breaker may be 20 amp and it has 12 GA wiring, the receptacle used on the vast majority of homes is a 15 amp receptacle. The 20 amp breaker and wire is installed to handle multiple outlets. If it doesn't look like this with the horizontal leg, it's probably a 15 amp.

[wa8yxm]

No the smaller outlet won't damage the RV, though the reverse may not be true.

What damages the RV is high or low voltage. Now. Depending on many things running an A/C on a 20 amp outlet may .. cause low voltage. (Due to voltage drop in the wires and extension cord) but.. If you check the breaker box in the RV for the breker marked AC or Air Conditioner or A/C (how I mark 'em) You will see.. 20 AMPS.. So no a 20 amp circuit is fine for the A/C.

YOu might want to make sure the house batteries are fully charged first though.. (LIke plug in for 2-4 hours) here are some numbers from MY RV yours may vary

A/C #1 13.9 amps A/C #2 13.5 amps (Both are 15000 BTU different maies)

COnverter, with very hungery batteries 10-11 amps

(Total 23-25 amps and CLICK of darkness ensues.

Converter with FULL batteries (or in absorption mode) 1-2 amps. NO click of darkness (With a single A/C running.

[Joe417]

I've found several times over the years that even though I was pulling only 15 amps or a little less with the camper plugged into a 15 amp outlet, that the outlet wasn't capable of handling continuous maximum current. The adapter got hot and melted the receptacle.

This may have been with an older outlet which had loose contacts.

I say 15 amp outlets because that is what (in our area) many houses have installed even if there is a 20 amp breaker and 12 awg wire. Check it. If it is a real 20 amp receptacle in good condition it may work fine.

You can also buy a 30 amp replacement standard receptacle for a few dollars which can handle a bit more current.

A 30 amp RV receptacle in our area is only about $12.

[time2roll]

Kill-A-Watt is great in the RV.

No real use to measure amps from the home supply outlet as it is only rated 15 amps and that would be the wrong place to monitor voltage.

[MEXICOWANDERER]

DOGPILE

It's the cumulative effect of every other load piled on that is the deal breaker

[DinTulsa]

Another option would be to just run my bedroom 13,500 AC that is ducted as well. It would draw a few less volts/amps.

[AllegroD]

2oldman wrote:

time2roll wrote:
Check voltage stays 108+ in the RV and you are good to go all day..

x2

This is important because as voltage sags, amps increase, which can cause your sockets and plugs to heat up. If they don't get scalding hot in 15 minutes you're probably ok.

And heat shortens the life of your AC.

[Unyalli]

DinTulsa wrote:
Which kill a watt do you currently use?

Click the link.

- Jeff

[DinTulsa]

Which kill a watt do you currently use?

[Unyalli]

X2 on the Kill-a-watt. You can also use it to verify small appliance amp draw.

I use my RV as my home office on work from home days. I have a kill-a-watt visible and run my laptop with two big monitors and the Coleman Mach III 15k air conditioner. I'm in a 20 amp circuit off the garage and my voltage in the RV is 120-124 unloaded. When the AC kicks on it drops to 115-118 so no problem.

- Jeff

[Sam_Spade]

DinTulsa wrote:

My concern is that a 110/20 amp outlet will damage the unit?

No, you have it backwards.

IF.....the breaker doesn't trip AND the extension cord doesn't get hot at either end, you should be fine.

[pianotuna]

Hi,

Add an autoformer.

TurnThePage wrote:
I can rarely reach an hour of operation before the kill-a-watt is reading lower than I'm comfortable with.