Can I run my AC off 20 AMP 110?

[Natesms]

I'm going to be tied up to a dock for a week that has a standard 110 V 20 AMP outlet. Before I buy a 110 15 A --> 30 A shorepower adapter, do you think it will be able to run my air conditioner (and only my a/c)? I don't know the exact information on my A/C unit but it's a 33 ft boat if that helps at all. I will be able to go direct from adapter to my shore power cords. My camper was very sensitive to this type of setup and I really don't want to cause any damage to the boat's A/C.

 

[fhhuber]

Depends on the AC unit...

 

[Natesms]

Depends on the AC unit...

One of those "just try it" things, or if I pull some numbers from the AC unit would that help?

 

[fhhuber]

Picture of the label plate for the AC

Similar to : https://www.google.com/search?q=Air...X&ved=0ahUKEwiNkI_CkYvLAhVC3mMKHW7XAPQQsAQIGw

 

[JoLin]

Picture of the label plate for the AC

Similar to : https://www.google.com/search?q=Air...X&ved=0ahUKEwiNkI_CkYvLAhVC3mMKHW7XAPQQsAQIGw

Yup, find the spec plate. The 9000 btu unit in my Carver pulls 8.3 starting amps and 4.0 running amps. Guessing that the unit in your 33' is in the12,000-16,000 btu. range. Chances are that you'll be okay, but it's best to know for sure. If you decide to just try it (which I don't recommend) and the breaker doesn't trip at start-up, periodically put a hand on the the 20/30 amp adapter- if it's warm, shut it down.

My .02

 

[H20Rat]

There are some tricks you can do that help also.. Start up the fan of the AC first and lock it to always-on, if you can. Then kick it into AC mode... The problem isn't the running current, it will be the startup load, and this helps reduce that.

The roof AC in my RV is a 9000 btu, and is usually OK on a 15 amp circuit. If I end up at a spot with lots of extension cord between me and the circuit, I sometimes have to use the fan-first trick above to avoid popping a breaker.

 

[Natesms]

Thanks for the replies. I'll get a picture of the plate next time I'm at the boat.

I'm really just being cheap and don't want to buy the adapter if it won't work. It's probably handy to have though, if I can't run the A/C unit I can still plug it in to run the battery charger.

 

[Natesms]

No Title

Finally made it back to the boat and grabbed pictures of the plate. Says input amps of 14.9 and 50 amp max. Does that mean a minimum of 15 amps to run it?

 

[JoLin]

Wish I could read the 'model' off that tag. Dometic Cruisair is in business and you have the serial number. Call them. That 14.9 amps figure seems too high for a 12000 BTU unit. Cruisair's specs on their 12,000 BTU 'Stowaway' A/C specifies 8.7 start-up amps for cooling and 10.9 amps for heat.

 

[Tnstratofam]

I believe that 14.9 is the minimum breaker size for that with 50 being the max. That is a big range and I may be missreading that plate. I wouldn't think it would pull more than 9 or 10 total amps running, but as has been mentioned it's the startup amps that will get you if they exceed the 20 amp hook up you're tied to for long.

 

[Natesms]

Wish I could read the 'model' off that tag. Dometic Cruisair is in business and you have the serial number. Call them. That 14.9 amps figure seems too high for a 12000 BTU unit. Cruisair's specs on their 12,000 BTU 'Stowaway' A/C specifies 8.7 start-up amps for cooling and 10.9 amps for heat.

Found the model on another picture (was not easy getting them), it is SX12. I found that last night on the Stowaway as well. I tried digging through their manuals but had issues. I did find this link that says full load amps is 14.3.

http://www.oya.com/others/airstow.html




It's good to know that based on the stowaway the amp draw is more for heat vs AC.

 

[JoLin]

I'd still call them with the model and serial number and have them verify how many amps you'll draw- start-up, running and heat. Is your heat by reverse cycle or resistance? My unit has resistance heat rather then reverse cycle, and it draws just under 14 amps in heat mode.

I don't understand that 'full load amps' figure, unless it refers to the current draw for resistance heat, if that's what you have. It's simply too high to be the actual 'draw' of a 12,000 BTU cooling unit in operation.

My .02

 

[StarTed]

Most circuit breakers are rated 80% for continuous load like your AC unit running. A 20 amp breaker can handle 16 amps continuous. A 15 amp breaker can handle 12 amps continuous. Breakers are usually thermal operated so it'll take a pretty good starting load to trip them. However they may have a magnetic limit. I'd say you're all right if you're within the operating range of the breaker for the continuous load.

 

[Natesms]

In case anyone runs across this post...I gave it a shot this weekend off a 20 amp outlet and it popped the breaker immediately when the A/C tried to kick on. I will try another 20 amp source next weekend but it's not looking like 20 AMP can handle the startup load.

 

[Tnstratofam]

The problem arises due to the start up amp draw. Also try to be sure nothing else is drawing current from the breaker if you can.