A/C Tripping Genny Breaker

[joemar1112@yahoo.com]

My A/C units seem to be working. However, after about 15 minutes they trip the Main Breaker on the Genny. The Genny keeps running, of course, without sending any juice back to coach.

Has anyone run across this problem? For some background info, when I bought the coach in February I drove it north to PA, and have had some small issues from it not having been winterized. Could lack of winterization have caused something to go awry in the A/C units, to cause this problem? I have not hooked up to shore power to run a test to see if the A/C will trip the main breaker.

[wolfe10]

What generator do you have (and what watt)?

What A/C?

Have you looked at the voltmeter when this happens-- what is the voltage (and does it drop off just before the generator breaker trips)?

Is this the first time the generator has been used in awhile? If so, did you either run it out of gas (only assuming gas-- model above will tell us) or add Stabil to the gas before storing?

Brett

[garykd]

Hi joemar1112,

In addition to Brett's post, please connect the coach to shore power and run the A/C. Also, with the coach not connected to shore power, run the generator without running the A/C. Please let us know if the symptoms remain the same and what the result was from these two requests.

[utahborn47@gmail.com]

I had a similar problem in our Barth. I finally replaced the unit which was original from 1993 since I assumed it was going on the fritz. I had done all the normal checks including the 120V supply and all was well. After installing the new Dometic AC I went to test run it and guess what, it would not start. I then did another check of the AC voltage and found that I had an intermitent neutral. I then had the wonderful experience of pulling a new run of 12 AWG Romex cable from the 120VAC panel to the roof AC unit.

Prior to replacing the unit I had noticed that if I banged the wall, stomped on the floor, etc. the unit would shut off and on. Apparently what was happening was that the neutral would open then quickly reclose the circuit. This would put the roof AC unit into a stalled compresor condition which is, for all practical purposes, a direct short circuit. Since the other roof AC unit was running, along with other 120VAC items, the draw on the generator would exceed the generator's output breaker rating before it exceeded the AC unit's breaker.

Since the old unit was 16 years old I decided to go ahead and had it properly disposed of. I also had the local RV shop do a complete check of my generator just for my own piece of mind.

I hope my ramblings are of some help.

[wa8yxm]

One cause I've found for the A/C tripping breakers IN SOME PARKS is low voltage.

When the voltage goes down.. the Current in an A/C goes up. If the voltage starts dropping much below 110 then the current REALLY goes up.

This can also damage the Air Conditioner. There is a way to prevent damage, but this too,,, Increases the current and thus trips the breakers even faster.

Suggestion is a volt meter.. My personal favorite for general plug in use is the Kill-a-watt in volt meter mode. This is about a kilo-buck worth of meters ($1,000) in a 30 dollar OR LESS box.

Watch the voltage especially when the A/C's kick in.

[Digitalsteve]

Could be one or more of the following:

A. Since the electrical panel breaker for the AC unit does not trip, the total load on the generator may be near the limit. I.E. You have othe things pulling power from the generator or something else comes on like the frig, waterpump, electric water heater, etc when the AC unit is running. (As has been suggested, see if the AC unit runs on shore power and does not trip the breaker in the panel. This will give you a good indication that the AC unit is OK)

B. A loose connection between the AC unit and the electrical panel or between the electrical panel and the generator could heat up after 15 minutes of heavy load and the generator breaker trips. Since the eletrical panel breaker for the AC unit does not trip, then I suspect the problem may be between the generator and the electrical panel.

C. The circuit breaker on the generator may be bad. ( A loose connection at the breaker can cause heat that will damage the breaker. check to see that the connection is tight and there is no dis-coloration from being hot.)- vibration from use can sometimes loosen the connections.

Placing a clamp-on amp-meter on the output of the generator will tell you if the load is exceeding the breaker rating. If it is not, then the breaker is bad, if the load is near or above the rating of the breaker, then you need to see what is using the power.

Good Luck

Steve Snyder

Electrical Contractor