Can I run RV A/C while hooked up to 20amp outlet

[chefred112]

Hi All,

When the rv is home I run an extension cord from a 20 amp outlet to it to keep it on ac. Not sure what I was doing at the beginning or what appliances (probably ac) I was using but I would always kick the breaker on the house outlet. Through trial and error I figured out I can do normal stuff and not use ac while plugged in at home and have not kicked the breaker since. From what I'm reading in posts is that ac's draw alot to start the compressor but not as much while it's running. With that said, what I have been doing if I want ac is to turn on the generator and keep it running while using ac. But, with the theory I mentioned earlier, can I:

1) turn on generator
2) turn on ac a few moments later
3) turn off generator after a few minutes and just run off the 20 amp outlet.

thanks all for input.... Fred

[wolfe10]

No, not recommended.


As you switch power sources, the A/C will shut-off and instantly try to restart (unless there is a delay for compressor start built into your particular A/C).


So, power draw would be at least as high on restart.


Try shutting everything else off and monitor voltage when the roof A/C comes on. Size of house wiring and extension wiring make a difference here.


If voltage after start up does not drop below 108 VAC, you should be OK to run just the A/C on 20 amps.

[NorthernDriv]

I just read about this thing.....


https://www.softstartrv.com/rvlife/?utm_source=RVLIFE

[carybosse]

With the caveat that most homes I have owned had the breaker box in the garage, I would look to have an outlet installed next to the breaker box with an appropriate size breaker/outlet. On my current house, I could probably even set up the outlet on the outside wall.

When my wife wanted to run an oven to fire ceramics, I installed the appropriate breaker and an outlet just below the breaker box. We could open the garage door, set the kiln right at the doorway, and fire it up.

[ddowntown]

I would absolutely not recommend using a 20amp through an extension cord to connect to your coach. I actually speak from experience, I used an extension cord to connect my coach and cooked my transfer switch due to a low voltage situation. Get a dedicated 30 amp or 50 amp without a GFI. GFI outlets just don’t seem to work well with Newmar coaches for shore power.

[gatorb8]

if you have an outlet circuit with 20 amos available (no other outlets pulling current) and you have a good power cord (10-3 or 12-3) you will be fine, I do it all the time. I have an ac readoit in the rv snd it drops from 120 volts to 113 volts, well within good voltage range

[wolfe10]

Originally Posted by ddowntown

I used an extension cord to connect my coach and cooked my transfer switch due to a low voltage situation.

No question, it doing REQUIRES that he monitor voltage under load.



Since we don't know the gauge of house wiring, condition of the outlet or gauge and length of the extension cord, all we could do is speculate-- NOT helpful, as he needs to base his decision on FACTS.


Agree, everything has to be just right for this to work, but if everything is good, it will work. Been there, done that.

[outlawten5]

Call an electrician and get a dedicated 30amp plug installed. Should solve all your problems and not too expensive

[TJ]

No, no, no...please, NO! Really bad idea!

First, a 20A household circuit is marginal...at best...for running even a single RV AC, much less starting it. And, that assumes nothing else is connected to that circuit. Household circuits usually feed several outlets and lights, so other things could also be pulling power from the circuit.

Trying to hot switch between the generator and AC overlooks the built-in time lag at changeover in the transfer switch. This will definitely shorten the life of the transfer switch. And, they are neither cheap nor easy to replace.

Then, adding an extension cord between the RV and 20A household outlet makes things a lot worse. Even with “heavy duty” extension cords, there will be a “line loss” aka voltage drop. The longer the extension cord, the greater the line loss.

And, the 113V observation means that the AC is running well below its design spec voltage which will shorten the life of the unit significantly. Again, they are neither cheap nor easy to replace.

For anything beyond keeping the RV batteries charged and—maybe—the refrigerator running, you need at least a 30A dedicated outlet; preferably a 50A. It should be installed by a qualified electrician that understands RV electrical service requirements.

TJ

[carybosse]

Originally Posted by TJ

...

For anything beyond keeping the RV batteries charged and—maybe—the refrigerator running, you need at least a 30A dedicated outlet; preferably a 50A. It should be installed by a qualified electrician that understands RV electrical service requirements.

TJ

SO, I guess I shouldn't do that anymore?

Honestly, a trained person is important. I have wired up 3 phase, 100 amp circuits, etc. I spent a large amount of time before I wired that Kiln I described, made sure I had the right gauge conductors, and even spoke to a licensed electrician that I worked with at the time. And there was no, I repeat, no extension cord involved.

I did purchase a heavy duty extension cord to run my popup camper off a household circuit, but I did not run the ac with that setup. Just charged batteries, ran the lift, etc. Didn't even run the fridge.

[gatorb8]

Originally Posted by TJ

No, no, no...please, NO! Really bad idea!

First, a 20A household circuit is marginal...at best...for running even a single RV AC, much less starting it. And, that assumes nothing else is connected to that circuit. Household circuits usually feed several outlets and lights, so other things could also be pulling power from the circuit.

Trying to hot switch between the generator and AC overlooks the built-in time lag at changeover in the transfer switch. This will definitely shorten the life of the transfer switch. And, they are neither cheap nor easy to replace.

Then, adding an extension cord between the RV and 20A household outlet makes things a lot worse. Even with “heavy duty” extension cords, there will be a “line loss” aka voltage drop. The longer the extension cord, the greater the line loss.

And, the 113V observation means that the AC is running well below its design spec voltage which will shorten the life of the unit significantly. Again, they are neither cheap nor easy to replace.

For anything beyond keeping the RV batteries charged and—maybe—the refrigerator running, you need at least a 30A dedicated outlet; preferably a 50A. It should be installed by a qualified electrician that understands RV electrical service requirements.

TJ

the specified voltage for my ac is 115 volts, hardly think 113 volts will damage it. And yes, I have an EE degree.
If you can supply the specified voltage and current to your ac via a 20 amp circuit and extension cord, you will be fine, just measure/monitor it and decide.

[wolfe10]

Originally Posted by gatorb8

the specified voltage for my ac is 115 volts, hardly think 113 volts will damage it. And yes, I have an EE degree.
If you can supply the specified voltage and current to your ac via a 20 amp circuit and extension cord, you will be fine, just measure/monitor it and decide.

Yup, savvy owner-- may work.


"Plug and play" owner-- don't do it.

[Russ Silber]

Run my ac off 20 amp circuit through 30 amp plug and rv power cord. Never a problem.

[carybosse]

Originally Posted by Russ Silber

Run my ac off 20 amp circuit through 30 amp plug and rv power cord. Never a problem.

No mention of an extension cord in the circuit.

I know this may sound like a minor issue. but every foot of copper adds little bit more resistance, every plug & socket adds another little bit more resistance. A few ohms here, a few ohms there, and pretty soon you have a significant voltage drop.

(This is much worse on a 12 volt circuit as opposed to a 120 volt circuit. )