As was mentioned briefly in a previous post if the connection is loose it will cause heat to build up and trip the breaker. With the generator off and not connected to shore power try tightening the screw on the breaker that holds the power wire. If it is not tightened firmly it could cause your problem.
If that is not loose then I would replace the breaker.
Jerry & Dee Dee Pauley
1998 Pace Arrow 36S, 1 Slide, 1 Tag, 1 Triton V10, 2012 KIA Soul Toad
The happiest people don't necessarily have the best of everything. They just make the best of everything they have.
Thanks for all the replies so far. You guys have collectively given me quite a bit of info and planted some good thoughts/ideas in my head as to where to go with this. I still haven't been out to the storage place to see my rig yet (since starting this post). However, as I sit here and think about it (prompted by stuff you guys have mentioned) it occurs to me that *almost* certainly my 2 A/C units are going to be running through two difference circuit breakers. If they were tied through a single circuit breaker it would have to be a much larger one. Something like 40-amp I'm guessing. My vague memory of my circuit breaker panel is that the one(s) that tripped were just the smaller 20-amp style breakers.
Now... my memory of this is prone to be faulty/fuzzy, but..... I'm thinking that the time it tripped when I was with the unit that *maybe* it was just the front A/C which tripped. Unfortunately, I wasn't around for the other tripping episodes and my wife wasn't observant enough to remember stuff like this (she figures I'll take care of it I think).
At any rate, my to-do list now has a few good suggestions on it and if I/we encounter this in the coming summer months I have a good idea how to diagnose and isolate where the problem is. I've also decided that we are gonna pay my electrician-cousin a few bucks to install a 50-amp receptable outside the inlaws and outlaws house(s) where we'll be parked for much of the summer. That way we can keep the inside of the rig a bit cooler.
I'll report back when/if I ever figure out anything definitive. Meanwhile, I love all this feedback and suggestions. Please don't hesistate to keep it coming...
Constructive disagreement is encouraged. It is how I/we learn!
I think you've gotten to the heart of it. There will be a single main breaker for the whole system - that is probably not tripping. Your generator may be set up for 240 volt AC if you have a "50 amp" coach, in which case you may or may not have the AC units fed from a single side, or fed from different sides. If they are fed from just one side of the generator, both on at once would indeed be a big load on the gennie. Something to check out. Code requires each AC to be fed from a separate breaker, but I don't think there is any requirement to have it on opposite sides of the 240VAC feed from the generator.
Also - a breaker is rated at 80% continuous current and normally at 40 degrees Celsius (even in the US, breaker temps are rated in Celsius). 40C is 104 degrees Fahrenheit. 80% of 20 amps is 16 amps continuous, which would be de-rated above 104 degrees, the air conditioner will be working hard at that high temp and drawing a little more current than normal, combine that with a slightly under rated or old breaker, you will get your problem.
Minor update. Went to visit my rig today. Looked at generator and realized it is an Cummins Onan RV QD 8000 (not 7500 as I said earlier)....Model 8HDKAK-1046M. So even a bit more power than I said earlier...
Also confirmed that front and rear A/C run through separate 20-amp breakers.
Also got some pictures of my oil and primary fuel filters so maybe I can find the right replacement filters for changing them
flyswamper wrote: Minor update. Went to visit my rig today. Looked at generator and realized it is an Cummins Onan RV QD 8000 (not 7500 as I said earlier)....Model 8HDKAK-1046M. So even a bit more power than I said earlier...
Also confirmed that front and rear A/C run through separate 20-amp breakers.
Also got some pictures of my oil and primary fuel filters so maybe I can find the right replacement filters for changing them
You dont need pictures of filters to find the correct ones?
Either get the part Numbers off them or go by engine type and serial number.
rgatijnet1 wrote: Difficult question but it may be a simple fix. First....breakers DO sometimes go bad and will trip because they are not functioning correctly anymore.
The current draw for any object is based on the voltage. In other words if an appliance is rated at 1200 watts and the voltage is at exactly 120 volt AC, the current draw will be 10 AMPS. Voltage times current in amps equals wattage. Now, lets say that from your generator, or shore power, the voltage drops to 100 volts(just an example for easy math) while under a load. Now voltage at 100 volts would need 12 AMPS to equal the 1200 watts. The circuit breaker on that line is now passing 12 amps instead of the previous 10 amps.
IF your two AC units are drawing the max amount of current because of the outside temps, compressors running, fans on high, etc, and the voltage from your generator is a little low, it could easily exceed the capacity of your circuit breaker.
The statement that breakers fail and trip for no reason is absolutely true. BUT the "increasing amperage with voltage drop" is misleading to say the least. Some inductive loads will draw more current at a lower voltage... true. This is true only to a point and not true anytime with any resistive loads. Ohm's law is always correct. I = E/R or Current equals Voltage divided by resistance. The resistance of most all loads does not change so a drop in voltage means a drop in current. If you have a 120 volt heater that draws 10 amps and the voltage drops in half, it does not draw double the current but draws half the current. If what you say held true, dropping the voltage to a few volts would increase the amperage astronomically.
Most all newer RV air conditioners have a low voltage protection device that will shut down the compressor when the voltage drops, removing it from the draw on the breaker.
Loose connections at the breaker can also cause tripping/overheating. Be sure to check those.
rgatijnet1 wrote: Difficult question but it may be a simple fix. First....breakers DO sometimes go bad and will trip because they are not functioning correctly anymore.
The current draw for any object is based on the voltage. In other words if an appliance is rated at 1200 watts and the voltage is at exactly 120 volt AC, the current draw will be 10 AMPS. Voltage times current in amps equals wattage. Now, lets say that from your generator, or shore power, the voltage drops to 100 volts(just an example for easy math) while under a load. Now voltage at 100 volts would need 12 AMPS to equal the 1200 watts. The circuit breaker on that line is now passing 12 amps instead of the previous 10 amps.
IF your two AC units are drawing the max amount of current because of the outside temps, compressors running, fans on high, etc, and the voltage from your generator is a little low, it could easily exceed the capacity of your circuit breaker.
The statement that breakers fail and trip for no reason is absolutely true. BUT the "increasing amperage with voltage drop" is misleading to say the least. Some inductive loads will draw more current at a lower voltage... true. This is true only to a point and not true anytime with any resistive loads. Ohm's law is always correct. I = E/R or Current equals Voltage divided by resistance. The resistance of most all loads does not change so a drop in voltage means a drop in current. If you have a 120 volt heater that draws 10 amps and the voltage drops in half, it does not draw double the current but draws half the current. If what you say held true, dropping the voltage to a few volts would increase the amperage astronomically.
Most all newer RV air conditioners have a low voltage protection device that will shut down the compressor when the voltage drops, removing it from the draw on the breaker.
Loose connections at the breaker can also cause tripping/overheating. Be sure to check those.
Wasn't the OP talking about his AC units? I'm not sure where you thought I was talking about heaters. My mistake for trying to keep things basic and just answer his question.
If he asks a question about heaters or light bulbs, go for it.
rgatijnet1 wrote: Difficult question but it may be a simple fix. First....breakers DO sometimes go bad and will trip because they are not functioning correctly anymore.
The current draw for any object is based on the voltage. In other words if an appliance is rated at 1200 watts and the voltage is at exactly 120 volt AC, the current draw will be 10 AMPS. Voltage times current in amps equals wattage. Now, lets say that from your generator, or shore power, the voltage drops to 100 volts(just an example for easy math) while under a load. Now voltage at 100 volts would need 12 AMPS to equal the 1200 watts. The circuit breaker on that line is now passing 12 amps instead of the previous 10 amps.
IF your two AC units are drawing the max amount of current because of the outside temps, compressors running, fans on high, etc, and the voltage from your generator is a little low, it could easily exceed the capacity of your circuit breaker.
The statement that breakers fail and trip for no reason is absolutely true. BUT the "increasing amperage with voltage drop" is misleading to say the least. Some inductive loads will draw more current at a lower voltage... true. This is true only to a point and not true anytime with any resistive loads. Ohm's law is always correct. I = E/R or Current equals Voltage divided by resistance. The resistance of most all loads does not change so a drop in voltage means a drop in current. If you have a 120 volt heater that draws 10 amps and the voltage drops in half, it does not draw double the current but draws half the current. If what you say held true, dropping the voltage to a few volts would increase the amperage astronomically.
Most all newer RV air conditioners have a low voltage protection device that will shut down the compressor when the voltage drops, removing it from the draw on the breaker.
Loose connections at the breaker can also cause tripping/overheating. Be sure to check those.
Wasn't the OP talking about his AC units? I'm not sure where you thought I was talking about heaters. My mistake for trying to keep things basic and just answer his question.
If he asks a question about heaters or light bulbs, go for it.
1. Does the trip on APU happen when stationary or ONLY when in transit? This is critical for a possible fix.
2. Will EITHER AC trip intermittantly or only 1 and which one?
3. WHERE is the Breaker panel located in the RV (exactly).
4. As you found out and for anyone else, NO RV will have 2 AC units on one breaker. NEVER
5. And it IS the Breaker panel AC breaker tripping NOT the APU breaker?
6. Do you have an EMS managment system? Most Monaco's use the Intellitec EMS system.
Doug
* This post was
edited 03/16/12 07:11pm by an administrator/moderator *
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