AC on 15A service

[darkskyseeker]

I successfully ran the Dometic AC on my FR Wildwood yesterday using a 15A supply from the house so I have a couple of questions:

1) was this safe?

2) if it works on a 15A circuit, do I need to go get a Companion Honda to supplement my original Honda 2000i?

3) if the answer to #2 is "no", I am willing to juggle the electrical usage, rather than plunk down $1000 for the second generator.

[Simplewon]

Running ac on under rated amps will cause excess heat within the units motors creating potential for early failure. As info.

[325BH]

Originally Posted by Simplewon

Running ac on under rated amps will cause excess heat within the units motors creating potential for early failure. As info.

Running anything on an underrated "amps" breaker will do nothing other than trip the breaker. The source is your utility and has all the amps in the world to give. It is only your breaker that will see too much current and trip. An undersized breaker will not "limit voltage " or "limit amps"... it will simply work until it trips. No "brown-out" with a breaker... it is either on (closed) or off (open).

Long distances of too small of wire can cause voltage drop, which is bad, but that isn't what is going on with a 15 amp breaker. If you use an extension cord plugged into a 15 or 20 amp breaker, you will want a "fatty" (12 gauge or thicker) to prevent voltage drop and overheating on the cord and potentially causing problems with your ac (or any device) due to voltage drop.

On the other hand... when talking about generators, they do not have unlimited capacity (like the utility company) so you have to get them big enough. Trying to start an ac with an undersized generator can cause damage.

[MeepMeep]

Originally Posted by darkskyseeker

I successfully ran the Dometic AC on my FR Wildwood yesterday using a 15A supply from the house so I have a couple of questions:

1) was this safe?

2) if it works on a 15A circuit, do I need to go get a Companion Honda to supplement my original Honda 2000i?

3) if the answer to #2 is "no", I am willing to juggle the electrical usage, rather than plunk down $1000 for the second generator.

Personally, I'd check the current draw for the AC unit to make the decision. Just because you got it to work in the short term doesn't mean it'll continue to serve under max load. Could be a penny wise, pound foolish situation

Good Luck!!

[darkskyseeker]

Originally Posted by MeepMeep

Personally, I'd check the current draw for the AC unit to make the decision. Just because you got it to work in the short term doesn't mean it'll continue to serve under max load.

Based on what is already written here, I am buying the 2nd generator.

[325BH]

Originally Posted by darkskyseeker

Based on what is already written here, I am buying the 2nd generator.

I have two Honda 2000 generators and are very pleased.

[Iwannacamp]

If you have an EMS it will warn you of low voltage or higher than acceptable amperage

[Retired JSO]

Is it safe, probably not. Mine has gotten so hot, the adapter to cord plugs melted together.

[llr]

Could be bad in several ways. Breakers don't generally trip until 120-150% of rated size sustained load. This can cause the breaker to stick and never trip.
Even if the breaker is ok are all the wire sizes and connections up to the task, if it is getting warm anywhere it is an issue, unless you know every where the wire goes I would not do it.
If you do it I would check the voltage in the house and the camper with the AC on, if the camper is more than 5 volts lower I wouldn't do it either

[Waterops1]

I just ran my 13.5 AC off a 15 amp receptacle in my driveway. I had run it using 12 AWG THHN wires but still off a 15A breaker. I just installed an EMS in the trailer and it was showing 13 to 15 amperes and 119 volts. I don't believe a C/B is going to "stick" if it runs a sustained overload. They are designed within certain curves and there should be no issues. AC ran fine and cooled but I am not going to continue that way more than necessary.

That being said, I do have a TT-30R box and receptacle on order from the big orange store so I can use 10/3 all the way w/o any adapters.

[Waterops1]

Just checked and should say, my AC is not Dometic but rather an Airxcel Model 48253 C 969 in a little Viking 21RD. But still a 13.5 K BTU unit. Not that it should be any different. (No doubt just a cheaper unit in this entry-level TT)

[Herk7769]

I have to say that the Micro-Air Easy Start looks like it is worth the money if you can truly avoid the second Honda.

https://www.youtube.com/watch?v=soP0...ature=youtu.be

https://www.youtube.com/watch?v=p2K0ptvYb6Q

[rockfordroo]

Originally Posted by Waterops1

I just ran my 13.5 AC off a 15 amp receptacle in my driveway. I had run it using 12 AWG THHN wires but still off a 15A breaker. I just installed an EMS in the trailer and it was showing 13 to 15 amperes and 119 volts. I don't believe a C/B is going to "stick" if it runs a sustained overload. They are designed within certain curves and there should be no issues. AC ran fine and cooled but I am not going to continue that way more than necessary.

That being said, I do have a TT-30R box and receptacle on order from the big orange store so I can use 10/3 all the way w/o any adapters.

X2 on my Coleman-Mach (Airexcel). I do it in my driveway for short times. I have a 25 ft (probably 14 ga) extension cord to my overhead 50 ft (probably 12 ga) retractable extension cord, then the 25 ft 30amp TT cord. They don't seem to get hot. But I wouldn't run them all day.

[formerFR]

I'm always amazed at the amount of 'knowledge' that some seem to add so quickly when someone has such a simple question. Several have noted that somehow your power supply, and if it's coming from your home I would suppose it is 120v through a 100a or 200a breaker box, would somehow have ANYTHING to do with whether you would be 'hurting' your AC unit to power it thru one of the household 120v 15a outlets!... that's just bunk.

120v power is 120v power, period. The size of the breaker has NOTHING to do with 120v power to the AC, it ONLY limits the amount of amperage, or HEAT, thru the wires. If the wires get too hot(too much amperage pull from the AC unit), then it would TRIP THE BREAKER. This has NOTHING to do with whether the 15a outlet can properly power the AC unit. IT CAN.

Where you run into issues is when you have too many amperages thru the wiring to the outlet - for example, you are running the AC unit and you then also turn on the microwave, or the water heater, etc. Then the amperage required to run these items at the same time will eventually, if not immediately, trip the breaker. Period.

If you look in your coach at the breaker fro the AC unit, it will either be a 15a or a 20a breaker. Some AC units can easily run on a 15a, some larger ones usually have a larger 20a breaker. BUT, that doesn't mean that you are ABSOLUTELY limited to only being able to run a larger unit on a 20a outlet, but that it is set up that way so that on very warm, hot days, when the electrical lines and breakers themselves are already warmed by the ambient temperature, or you have a rear diesel and your breakers are near it, and you have traveled a lot that day, the breaker has enough 'room' to make sure it can easily run the AC unit without issue.

Yes, typically a 30a shore power is what your manufacturer will state as the minimum you need to run your AC, but they are also contemplating that you would not ONLY be running the AC, but also other items, even which may be on other breaker circuits, but that all together would trip a breaker less than that. 30a shore power is the 'default' rv park and campground power, but that doesn't mean that you can't figure out easy ways to still do what you want, just in a limited way...

use the 15a outlet, but cut all other draws off - such as the battery charger, water heater, etc.
if you must use an extension cord to reach from your shore cord to the house, then make sure it is rated to handle the load for the distance, though most are already designed for a minimum of 15 amps since that is generally the standard 'minimum' circuit on any home.

[EdJunior]

And from personal experience, my trailer will trip the breaker on 15 amp. 20 amp is fine, even with a TV and a couple of lights. But it will trip if too much is going.

[JohnNJean]

AC units don't pull that many amps RUNNING. The load is on start up. Generally, if you can start an AC you can run it with no problems.

The MicroAir units work and there is a lot of information available online about them. Look for a thread on the Airstream forum.

I spent a lot of time this winter experimenting with the MicroAir unit and found their support to be excellent. I wanted to run my 15K AC on a Champion 2000 Watt generator and we found that it would not start the unit. MicroAir said they had extensively tested their unit and found that it would reliabily run a 15K AC unit connected to a Honda. However, when I had problems, they bought a Champion generator, hooked it up to their test rig and found that the Champion didn't have the same amount of guts on startup.

FWIW, even after I found that the Champion wouldn't run my AC, I kept the MicroAir unit because it makes the AD startup much quieter - no more clunk. I highly recommend MicroAir. Champion inverter generators not so much.

[Retiredtwo]

Being a new owner this subject is a concern I have with running the Dometic 13500 BTU on a 2000W Inverter. If I can do it without too much trouble all the better. I purchased 2 2000W Inverters to be on the safe side however, if I can tote just one and be able to boondock in comfort all the better.

[Flybob]

The real issue is when the AC restarts after having just run for a while. The pressure in the compressor takes some time to equalize and if the unit tries to restart before the pressure equalized, the start current will be higher. You can run some items in the unit from 12VDC/propane, but that will most likely cause the converter to draw more current to replace that used from the battery. Short answer, it will work, but not consistently.

[formerFR]

Originally Posted by Retiredtwo

Being a new owner this subject is a concern I have with running the Dometic 13500 BTU on a 2000W Inverter. If I can do it without too much trouble all the better. I purchased 2 2000W Inverters to be on the safe side however, if I can tote just one and be able to boondock in comfort all the better.

are you meaning to say 2000w generators? Inverters only change 12v power to 120v, but Generators provide the 120v power directly. AC units don't run off of Inverters.

[kcmusa]

Your home service can supply the startup current the AC needs. a small generator can not.