Bad Breaker on Air Conditioner?

[deaton]

I'm having a problem with the circuit breaker on the forward air conditioner in my '08 Camelot. In this Texas heat we often drive with the generator on to run the air conditioners. Normally, we run the first two and leave the third unit (bedroom) off.

Lately, I've been having a problem with the circuit breaker for the forward unit tripping when on the generator. This is a separate 20 amp breaker on the Intelletec panel in the bathroom. The breaker does not trip when on shore power. The second unit (kitchen) is on a different breaker and it's running ok. The generator is an Onan 10k. Once it is reset, it's good for thirty to forty-five minutes, and it trips again.

I'm thinking it could be a weak breaker or something else on the same circuit that's adding to the load. But before I start to explore, I was wondering if anyone else with a similar coach has had a similar problem and what the cause may have turned out to be.

Thanks in advance...

[mahon1993]

It could be a weak breaker. As a test you could swap two 20a breakers and see what happens. Or, if you have a clamp on amp meter you could see how much current the front air is drawing. Could be something wrong with it. Of course, if you swap breakers make sure all power, shore and gen is OFF. And be careful when using the amp meter. HD and Lowes has them for a pretty reasonable price. A good tool to have around.
A tip an old electrician once told me when working in an engerized panel is to work with one hand while the other is in your pocket.

Greg

[bullydogs1]

I would try the new breaker...if it still happens, then the gene is either not supplying enough current to that circuit or the compressor with the unit is marginal and the resistance is tripping it. The fact that it is OK on shore power is pointing me to the breaker first....start there...and if it trips..there is something in the generator supplying the circuit...in fact, it could be the transfer switch when going to Gene Power somehow that circuit off the gene switch is not right when transfer switch on gene. I'd check the transfer switch connections and tighten them up but if you have any doubts, get the right person to work on it.

[Sammie]

Loose wire connections anywhere on that circuit can cause the breaker to trip. Try tightening all connections from the breaker to the generator and from the breaker to the air conditioner.

Sammie

[deaton]

Thank you'all for your suggestions. I check the connections and bought a new breaker and an ammeter. Today I went out to the RV garage and installed the new breaker and ran the generator for about an hour with the front A/C and the center A/C turned on.

The front AC showed to be pulling 12 Amps at start-up and then it climbed to 15.2 and stayed at that level (15.1 - 15.3). After running for one hour, the breaker did not trip so maybe I got off cheap with just buying a new breaker. Time will tell.

Thanks again.

[TandW]

Good for you!! Also keep in mind that the breakers are heat sources in and of themselves. If high draw circuit breakers are stacked adjacent or on top of one another, it invites an early trip below rating. So does lack of ventilation become a problem. Good luck!!

[wa8yxm]

Possible causes....

FIRST: go topside (up on the roof) and clean the condenser coils (This requries you remove the cowling) and anything else that needs cleaning, INside do the filters and evaporator coils.

Now, Suspect list includ low voltage from generator, This may be due to a generator problem, loose screw or connection, ATS issue or ].. Well there are other rare issues but these are the biggies.. Since it only happens on Generator I would check the Generator and up to and including the ATS. Beyond that should be good.

[Happycarz]

Dan,
One of my A/C breakers did the same thing. I don't remember if it was the front or rear. When I put my hand on the CB panel, it was quite warm, almost hot. Now when in hot weather, I just leave the cabinet door open so the ceiling register can keep the panel substantially cooler and now it doesn't trip out.

[deaton]

Thanks again everybody for the suggestions. I'll check the coils on the roof units this weekend.

Harry - Good idea on the cabinet. That vent in the bath keeps it pretty cold in there when the center unit is running, but I'll bet it doesn't do a lot of good cooling the CB box with those wooden doors closed. I'll try leaving the left one open too. As TandW mentioned and you know from your own coach, that panel is small and tight and the front AC breaker is third in line - right next to one of the 30 AMP mains.

[Rex]

Deaton, if it trips with the new breaker installed, have the generator checked for the frequency it is putting out. Should be 60 Hz but if it is much higher or lower, you have found the problem. Voltage could be alright even if the Hz frequency) is off.

["007"]

Check the wiring from GEN and from your load center in the transfer switch. You may have #12 romex wiring cable from load center and # 8 cables from Gen.
If any of the wire screws are loose will cause high resistance through these connections and heat or high current draw.
While your at it check the shore power cable also and surge protector if you have one.

[itdave]

I was told by Dometic that the amp draw of the A/C will increase as the outside ambient temperature goes up. I temps in the 100s the draw can approach 18 amps. so just because it is only 15 amps now it could go higher.

[Pusherpilot]

Quote:

Originally Posted by TandW Good for you!! Also keep in mind that the breakers are heat sources in and of themselves. If high draw circuit breakers are stacked adjacent or on top of one another, it invites an early trip below rating. So does lack of ventilation become a problem. Good luck!!

My 04 HR Imperial had a similar problem. The breaker in the row next to it was hot and causing the a/c breaker to trip. Circuit breakers are temperature operated devices. Another tip is that each time the breaker trips the value needed to trip it lowers. If it is tripped at rated value enough times the amount of current needed to trip it will decrease.
Another fact is that the a/c is a current operated device. As the current load increases the voltage can drop on the circuit, causing the device to draw more current to keep running. I had a recent experience at a 30a CG where I could run both a/c's on the 30a supply as long as the voltage stayed above 108, where the draw was 28-29a. When others started running their a/c's the current draw would increase to over 30a as the voltage dropped to around 105v. Thankfully the EMS would shut down the rear a/c only so I didn't get too sweaty!
Ron
04 Imperial

[wa8yxm]

I forgot to add.. Bad breakers do happen too.