50 amp MH, plugged into 30 amp, ok to run 2 ac units??

phillyg wrote:
I know some folks have reported running two ACs on 30a. Perhaps their RVs have a load shedding feature. I have two 15k ACs and I've tried this summer to run both, and it ain't happening. If yours seems to be working, I say "carry on."

We have a 50amp MH, 2 compressor A/C/Heat pumps, basement unit. We had a 30 amp site in FL. this spring. Fridge, water heater and A/C on all the time. The load shedding feature managed everything very well. I did turn off the breaker to the 2nd compressor near the end because the start cap blew but prior to that both compressors were online. I will add that with the basement unit ducted through ceiling vents 1 compressor did the job with temps in the upper 80's and the door open. Don't like to be closed in in a MH while camping. We were paying for electricity so that was one me, wasn't taking advantage of the park.

supercub wrote:
Something new for me. My motorhome has 50 amp service, however I'm currently plugged into a 30 amp outlet. Both my air conditioners are running. Is this ok to run both on 30 amps? Thank You
Brian

Don't know what you have here, but most likely you have an EMS that will shed the extra amps and the a/c compressors are usually first in line. One is usually not aware if both compressors are running at the same time or not, so.... If you're running, now, without tripping any main breakers, then all must be OK. We do it all the time at home, but then we're not heating water, microwaving and making toast either. Still the EMS would take care of it, no matter and just like in our old 30amp coach, one doesn't need ac while taking a few to make a pot of coffee or other and all power will be restored automatically once the load drops below 30amps.

Nice part of an old 30A MH. While I have to choose between the microwave or the washer/dryer I can run both AC'S, the fridge, the television, a fan, the fridge in the outside bin and one or the other mentioned above on 30A.

dougrainer wrote:
For ScottG. I looked up the breaker info at work from the NEC. Doug

Circuit Breaker Ampere Ratings

Circuit breakers have an ampere rating (typically marked on the end of the operating handle). This is the maximum continuous current that the breaker can carry without exceeding its rating. As a general rule the circuit breaker’s ampere rating should be the same as the conductor’s ampacity.

Pure nonsense Doug. You found all the same information I did on the subject and you post BS to back up your side. But your problem runs much deeper.
Your problem starts with not being able to have a civil conversation without going into attack mode. I see you do this quite often. For that reason I feel no need to prove anything to you. Your just not worth it.

For ScottG. I looked up the breaker info at work from the NEC. Doug

Circuit Breaker Ampere Ratings

Circuit breakers have an ampere rating (typically marked on the end of the operating handle). This is the maximum continuous current that the breaker can carry without exceeding its rating. As a general rule the circuit breaker’s ampere rating should be the same as the conductor’s ampacity.

I know some folks have reported running two ACs on 30a. Perhaps their RVs have a load shedding feature. I have two 15k ACs and I've tried this summer to run both, and it ain't happening. If yours seems to be working, I say "carry on."

MrWizard wrote:
i haven't had a NEC code book in many years
is that 'residential' or commercial/industrial ratings

Pretty sure that applies to commercial/industrial wiring. I don't believe there is any such language in the NEC related to residential wiring. Normally with residential wiring AC compressors will cycle on and off. Electric water heater and fridge, same thing. Is it possible for both AC compressors to run continuously for 3 hours, yes but that is not typical in residential setting. Commercial/industrial wiring code is different. Interior lighting may remain on 24 hours a day. Air handlers of other equipment is also expected to run for extended periods. Hence the difference in the code between commercial/residential and residential.

Monitoring the voltage is a different subject. NEC assumes the supply can handle the load without a voltage drop. We all know that may not be the case in many campgrounds so monitoring the voltage is a good idea.

And here's something else to consider. When voltage goes down, amperage goes up. And yes a 30 amp breaker is only good for 24 amps continuously. So, when one of your A/C units goes to **** don't bitching about it.

I knew when this topic was posted that it was trouble! There's real world and there is textbook....I happen to be a little of both. I know for a fact that I have run BOTH of my 15,000 BTU air's on 30 amp power and I happen to be blessed with a voltage/amp meter's on one display when connected to 30 amp and two display's when on 50 amp in the motor home. In 30 amp situations, I may or may not use my auto-former but always use my Surge Guard(over/under voltage protection too).

There are a ton of scenario's that say it can't be done yet it is done. I don't sit on top of my voltage meter's watching it as the compressor's go on and off generally because if I'm using both AC's , it's HOT and the compressor's are mostly on. My Refer is residential and it stays on, my batteries are generally already charged so the inverter/charger stays on. I will admit that I did just replace my front air(after 15 year's)...oh it's still work's but decided I wanted the Atwood ducted model instead of my Carrier non ducted.
Soooo, have at it and tell me how it can't be done and that I'm ruining my electronic's!

OH...there has also been plenty of times I couldn't do it also...more times than I could actually but if Hot, I'm always willing to try while keeping a close eye on things. :-)

ScottG.
Sorry, I DON'T LOOK UP info to prove you wrong. YOU do that. I have been an RV Technician for 38 years(still am) and I have NEVER seen any technical info for what you state as it pertains to RV's. Remember, until about 20 years ago All RV's were 30 amp. You want to post misinformation, it is up to YOU to prove you are right. Just not "someone" on the Internet told me. Doug