Roof AC won't Turn ON-breaker issues

[Larry and Heidi Lee]

Hi Fellow Beavers, I've been doing some camping in these 90 degree temperatures and both AC units have been running fine thanks to a 50A hookup. This week we are at a campground with only 30A hookups. I have been successfully running just 1 AC unit and alternating between the front and rear. Just yesterday I noticed the rear AC unit no longer turns on. I tried swapping thermostats-confirmed both good. Checked all the 12VDC fuses-Good. Switched the AC breaker off and back ON-same result-nothing. Front AC unit operates as it should. I tried to check for power in the ceiling at the AC unit but nothing. Finally I removed the breaker panel and removed the breaker to test continuity hoping I had a faulty breaker. Its at this point my wife Heidi pointed at the white output leads and said, "Can one of those be loose?"

I could hardly believe that the feed wire to the AC was just "resting" on top of the screw post. The screw post was tight! I found no broken lead in the post. Installed the wire and presto we now have AC. Thanks Heidi!

If you are having any intermittent AC issues check the wiring feeding into your panel (remove all power first). It could be your problem!  

[Don Beukers]

Do to vibration, all lugs should be checked for tightness, just remember you have voltage so turn off the breaker before checking.

[Larry and Heidi Lee]

Looks like I spoke too soon. Now the front AC doesn't work. What I realized is while troubleshooting I moved the rear AC breaker to the Front AC breaker spot that solved the rear AC problem. The Front AC doesn't work when plugged in the rear AC breaker slot.. I've tried using identical different breakers but still nothing happens when a breaker is plugged in the rear AC designated slot. I even took the rear AC breaker and tried it in the dryer slot-nothing. When I check voltages with my meter I show 115VAC to the black lead feeding the breaker and 115VAC along the metal breaker bar. Tried swapping breakers-same result. I'm not an electrician so I need someone to chime in here and tell me what happened.

[Steve Huber Co-Admin]

Larry,
If you haven't done so already, suggest you unplug from 30A shore power and fire up you geni to get a known good 50A supply. Then see if you still have a problem. If so, suggest you trouble shoot it using the geni so you have normal 50amps to supp;y both ACs.
Steve

[Larry and Heidi Lee]

Hi Steve, I just finished testing both AC units successfully with the generator. It's very rare I am stuck having to use a 30A service so I am not familiar with this issue. Apparently only the front AC unit will work on the 30A service. I guess I will know for certain when I plug in to the 50A service at home.

[Roy Warren Co-Admin]

Due to the load, your coach probably has one AC on each leg of the 50 amp service.  I believe one leg is isolated, i.e., not used, when plugged into 30 amp.

[Larry and Heidi Lee]

Thanks Roy, that explains everything.