AC Question

I am new to rving and have bought a 1992 36 foot carriage 5th wheel. I am going through the process of checking everything out. Good news is everything is working except for the roof a/c. It has a 50 amp service and the only plug I have at home is adapted down to regular 110 plug. That is running the fridge and all the lights in it. I thought it would maybe at least run the fans to see if it is working but I cannot get any lights or anything whatsoever to come on pertaining to the a/c.Is there somthing I am not doing or do I need to get bigger service plugged in to the rv. Do my batteries have anything to do with it. I wouldnt think they would but again I am new to this and have NO clue.Any and all help greatly appreciated!!

DL Rupper

Senior Member
Re: AC Question

I think you need to get a least 30 amps to turn most A/C compressors on. I would think the lights on the thermostat/controls and blower fans would turn on. Check the 115 V circuit breakers. There should be a panel of them somewhere. Mine are on the outside of the RV in a compartment.


Senior Member
Re: AC Question

When I had a 30 amp trailer, I was able to run the single AC from a 15 amp socket. 50 amp RVs usually have 2 or 3 AC units, and there is no way you will run more than 1 from a 15 amp socket, if even that. My 50 amp motorhome requires at least 20 amps to function, and then only will run 1 AC.

Often they have 1 AC on 1 leg of the 50 amp service and another AC on the other leg. The 30 to 50 amp adapter only powers 1 leg, so it is possible that the AC you are using is not on the leg being powered.
RE: AC Question

DOn't know much about electric as I've only been full time for little over a year in our 36' Carriage but the specs on our main AC unit require minimum of 30amp to run.
Re: AC Question

Adding a little to this, if you are 'wired' for 50-amp, then what you have is essentially a 220v/w ground. so your connections have 'two' 120 v legs. If you are connecting with only one 120 v connection, maybe you are not powering the AC at all!! Just a thought.