# Ac Tripping Breaker



## dherndonnc (Nov 11, 2008)

HIfolks, went down to Darlington for the race weekend before last. First time out with the Outback in 2013.

When I plugged in the camper to the 30 AMP circuit at the campground, the breaker immediately tripped (the Campground's breaker). After troubleshooting, it became apparent that the AC unit was tripping the breaker. We tried a 50 AMP with adapter, same result. We ran a drop cord over to another site's electrical panel, same result.

Anyone had this experience and might could shed some light on a quick fix before I haul it up to the RV Dealer?

I had one before that the capacitor had gone bad on it......easy enough fix. But that was years ago, and can't remember if it was the exact same problem.

Thanks!

Dave.


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## CamperAndy (Aug 26, 2004)

If you tripped the 50amp shore power breaker and not your 20 am AC breaker then the issue is not the AC.

Pull the covers to allow access to the ground bar and check all the ground screws. Also inspect the incoming power cables for loose connections.


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## dherndonnc (Nov 11, 2008)

Yeah, it's definitely the AC that's causing it to trip....not that the AC itself is causing the problem. With all other breakers turned off, as soon as you slide the switch to "cool" on the thermostat it would trip it.......and yet the Microwave worked.

I will go through it all and see if I can find any loose wires or bad ground connections......

Dave.


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## CamperAndy (Aug 26, 2004)

dherndonnc said:


> Yeah, it's definitely the AC that's causing it to trip....not that the AC itself is causing the problem. With all other breakers turned off, as soon as you slide the switch to "cool" on the thermostat it would trip it.......and yet the Microwave worked.
> 
> I will go through it all and see if I can find any loose wires or bad ground connections......
> 
> Dave.


Still not the issue but a symptom. Again if the 20 amp A/C breaker is not tripping and you tripped a 50 amp breaker at the site pole then it is something else other than the A/C unless the A/C breaker is welded closed..

Did you try fan mode? much lower current draw but could be informative on the issue.

Do you have a volt meter and comfortable in its use? There are many outer checks you can carry out.


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## Madmak (Mar 26, 2013)

The fan only or heat only would be a good test. If it stays powered in these modes you likely have isolated the A/C compressor and / or circuit. A thorough process of elimination looks to be in order as well as some voltage probing or AMP metering. Like all things mechanical, a good whack on the side with your fist may be what it needs to start the 2013 season, kinda like me.


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## CamperAndy (Aug 26, 2004)

robertized said:


> FYI; I can understand your simple logic that a 20A breaker should trip before a 50A but that is not an absolute. Circuit breakers are designed with a Short Circuit Current Rating that determines how quick a breaker will trip under certain conditions. This is to be able to design an electrical system to incorporate a calculation for Blackout Prevention, so a 20A downstream breaker trips before a 50A main. Not knowing the ratings of the two breakers and taking into account that the 50A breaker on the pedestal is operated more frequently, and allowing for wear and ambient temperature which effectively reduces the breakers rating and increases its sensitivity a 50A breaker could trip before a 20A. Good Luck.


Not really simple logic, if the breaker in the trailer does not trip, either the 20 for the AC or the 30 for the main and the trips happen at the shore power pole (multiple ones) then it is not the AC. The speed rating of the breakers should not be an issue.

The most likely location of the issue is where the shore power umbilical ties to the trailer.


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## thefulminator (Aug 8, 2007)

If the trailer breaker doesn't shut off but the power pole breaker does, chances are it is something between the two. Take a good look at your cable, plug on the end of the cable and connection where the cable ties to your trailer electrical panel.


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## CamperAndy (Aug 26, 2004)

I'll try to give a description of the possible issue.

For the shore power breaker to trip first, if there is a partial short in the umbilical, drawing current even with all trailer internal breakers open. Once a significant load is added the shore power breaker trips due to the combined load.

Test this by doing a current draw check with all breakers off.

I would open up the access to the shore power connection to inspect for shorts.


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