Puzzled that I'm able to run 15k A/C on our home 15 amp breaker

[montelovers]

Hello.
We have a 2019 FR Vibe with a 15k Dometic A/C on the rooftop.
After reading that they shouldn't be able to run off generators and the like, to our surprise after a neighbour told us he could run his off the 15amp extension to his house, our A/C actually worked and started cooling the RV.
I always thought that the 'initial' startup of the A/C would trip a 15 amp breaker.
I was proven wrong but still baffled.

[NXR]

Home breakers are thermally activated. If too much current flows too long through the breaker it heats up and trips. Your startup surge is likely lower than that time period.

Perhaps it's comparable to a window A/C.

Ray

[rockfordroo]

Most people can run their AC from a 15 amp outlet. Provided they are using a larger gauge extension cord that's not too long.

[Iwannacamp]

x2 I have done it also. I would chose a 12 GA or larger and keep as short as possible.

PS: make sure nothing else is on... FWIW my converter pulls 10 amps

[Kimber45]

Could be doing unseen long term damage from low voltage. Just cause the breaker doesn't blow doesn't mean its right.

[5picker]

Originally Posted by rockfordroo

Most people can run their AC from a 15 amp outlet. Provided they are using a larger gauge extension cord that's not too long.

X2.

Running a 15k A/C on a 15a breaker (or a generator) is doable if you have all things sized correctly, don't have loose/bad connections, have too long an extension cord run... AND... you are NOT using other things with heavy current draw.

Just running the A/C... easy peasy!
Remember... your A/C is connected to a 15a breaker in the R/V breaker box so even with a 30a/50a service, your A/C is really delegated to a 15a circuit so it makes sense it would run just fine off a 15a supply. (again, provided the above)

[madatme]

Originally Posted by montelovers

Hello.
We have a 2019 FR Vibe with a 15k Dometic A/C on the rooftop.
After reading that they shouldn't be able to run off generators and the like, to our surprise after a neighbour told us he could run his off the 15amp extension to his house, our A/C actually worked and started cooling the RV.
I always thought that the 'initial' startup of the A/C would trip a 15 amp breaker.
I was proven wrong but still baffled.

I also have a 2019 Vibe 28rl, my AC works also plugged into a dedicated 20amp Recep, no problems

[BUC-Steve]

I have a 2019 Flagstaff Micro Lite and also run my AC at home. I have a dedicated 20amp breaker with a 18ga extension cord and it all run fine. The cord doest’t get warm.

[montelovers]

Thanks everyone. I was probably confusing a home circuit vs a generator (like a 2200 Watt) that, from what I see, has problems even letting the A/C kick on.
I never really use the A/C at home but tried it more out of curiosity based on my neighbor's comments.

[llr]

Originally Posted by BUC-Steve

I have a 2019 Flagstaff Micro Lite and also run my AC at home. I have a dedicated 20amp breaker with a 18ga extension cord and it all run fine. The cord doest’t get warm.

It may not be getting warm but the voltage drop is probably fairly high, I would suggest at least a 12ga, smaller number is larger wire.

18ga sounds small for lamp cord, I think most of them are at least 16ga and probably most are 14ga.

Is that 18ga even a 3 prong (grounded) cord? I have never seen one that small in a 3 prong.

[Boomerweps]

Originally Posted by BUC-Steve

I have a 2019 Flagstaff Micro Lite and also run my AC at home. I have a dedicated 20amp breaker with a 18ga extension cord and it all run fine. The cord doest’t get warm.

Holy snikes! 18AWG is smaller than I use for home speaker cable. That is lamp extension cord size for 150-200 watt usage. And off a 20amp circuit breaker!
I don't know of any commonly available 18AWG cables with a grounded outlet.
Not getting warm? I'm stunned. Are you positive it's only 18awg? How long?

I have massive voltage loss using 12awg to my garage and TT when I use the TT air conditioning where I have the TT usually parked, about 120' or more from my home circuit breaker box. So much that I'm strongly considering running 10 or even 8awg to and through the garage.

[bubbles]

Or perhaps his home is like mine (built 1988) and all the receptacles are CB'd at 20 amp. In fact, I don't have one 15amp CB in my main power panel.

[formerFR]

...this discussion highlights the initial OPs 'concern' that he'd 'heard' that you 'cant' do this' and you 'cant to that' when using your RV....

many times you find 'old wives tales' to be false...

who knows 'how' these tales start, but they certainly are easily 'heard thru the grave vine', over and over and over... : /

[dhfenton]

Originally Posted by montelovers

Hello.
We have a 2019 FR Vibe with a 15k Dometic A/C on the rooftop.
After reading that they shouldn't be able to run off generators and the like, to our surprise after a neighbour told us he could run his off the 15amp extension to his house, our A/C actually worked and started cooling the RV.
I always thought that the 'initial' startup of the A/C would trip a 15 amp breaker.
I was proven wrong but still baffled.

You run your home AC on 15 amp circuits all the time. 15 amps at 110v is still a lot of juice. It’s unlikely you draw more than 13 amps, even at startup. As long as you don’t have other things running in your unit, you’ve got plenty of juice for one AC.

[formerFR]

...for the vast majority of the RVing public, you can certainly run one of your roof a/c units on a simple regular household outlet, if you limit the other things you are trying to power at the same time...

...and the same holds true for running two roof a/c units while on 30amp power...

[bedubya]

Originally Posted by Boomerweps

Holy snikes! 18AWG is smaller than I use for home speaker cable. That is lamp extension cord size for 150-200 watt usage. And off a 20amp circuit breaker!
I don't know of any commonly available 18AWG cables with a grounded outlet.
Not getting warm? I'm stunned. Are you positive it's only 18awg? How long?

I have massive voltage loss using 12awg to my garage and TT when I use the TT air conditioning where I have the TT usually parked, about 120' or more from my home circuit breaker box. So much that I'm strongly considering running 10 or even 8awg to and through the garage.

Wow is right. I think its hard to find an 18 AWG extension cord. Most of mine are 16 AWG, but I carry a 100' 12 AWG cord in my camper. I don't use it very often, but when "camped" at my daughter's it gets plugged in to her 15 amp outside receptacle. And the 13.5K A/C works just fine if I'm not brewing coffee and running the microwave.



At home, my shore cord reaches my garage 20 amp receptacle. So I can run everything in the camper. However, I did learn that I can't also run my radial arm saw

[RECONUSMC]

I looked at my Artic Wolf 5er and it has a 20 amp breaker for the 15,000 and a 20 amp for the 13,500 second unit. I would go to Home Depot and get a required length piece of wire and make my own ext cord with 30 amp plugs or this--https://www.homedepot.com/p/Southwire-50-ft-12-3-SJTW-USA-Outdoor-Heavy-Duty-Extension-Cord-with-Power-Light-Plug-2548SWUSA1/205544516

[5picker]

Originally Posted by formerFR

...this discussion highlights the initial OPs 'concern' that he'd 'heard' that you 'cant' do this' and you 'cant to that' when using your RV....

many times you find 'old wives tales' to be false...

who knows 'how' these tales start, but they certainly are easily 'heard thru the grave vine', over and over and over... : /

Amen to that!

Things like, "I run my A/C on an 18 ga. extension cord", are things newbies may take to heart. Hopefully they read enough posts to weed out the good from the bad.

[Bluepill]

This is an oscilloscope trace of my camper's A/C unit when it first comes on. This is attached to my home's 20 amp. outside service. Each peak across the top represents 1/60 of a second. You can see that within 6 peaks (1/10 of a second) the current drops close to the running value. The average house has over 40 thousand watts available to at the service entrance, so the startup surge has no effect on performance. Generators, however, usually have only 25-40 percent reserve capacity beyond their running rating, and often fall short of the startup surge.

[Iwannacamp]

Originally Posted by BUC-Steve

I have a 2019 Flagstaff Micro Lite and also run my AC at home. I have a dedicated 20amp breaker with a 18ga extension cord and it all run fine. The cord doest’t get warm.

I hope you are mistaken about the 18ga as cheap cords are usually 16ga.