A/C 20 Amp breaker tripping

[jramsey2008]

This is a relatively recent development for my 2017 Greyhawk 29 MV. The 20 amp A/C breaker trips after running about 20-30 minutes. Replacing the breaker had no effect. Upon closer inspection, all of the breakers are super hot. My quick fix wax to station a small fan next to the open breaker compartment. This worked and I can run the A/C as long as I want without tripping the breaker. Obviously, this is nothing more than a temporary, quick fix. I noticed that the compartment fan has never come on, but since that’s associated with the inverter, it should have no bearing on the breakers. Is the only remaining cause a bad A/C unit?

 

[pconroy]

all of the breakers are super hot

Not good!


Loose connections in any of them? Or are you saying the breakers stay cool, unless the AC runs and then all the breakers get hot?

 

[Scoutmaster253]

This is a relatively recent development for my 2017 Greyhawk 29 MV. The 20 amp A/C breaker trips after running about 20-30 minutes. Replacing the breaker had no effect. Upon closer inspection, all of the breakers are super hot. My quick fix wax to station a small fan next to the open breaker compartment. This worked and I can run the A/C as long as I want without tripping the breaker. Obviously, this is nothing more than a temporary, quick fix. I noticed that the compartment fan has never come on, but since that’s associated with the inverter, it should have no bearing on the breakers. Is the only remaining cause a bad A/C unit?

What is your inside and outside air temp?

 

[jramsey2008]

Hot breakers

I know the connections on the A/C breaker (20/15 combo) are tight, as replacing that breaker was my first step. When the new breaker tripped I noticed that all were hot. I’ll be replacing the single 15 amp breaker tomorrow (it seemed to be the hottest, though that could just be my imagination), and will recheck all connections then.

 

[jramsey2008]

I’ll also check the breakers before the A/C comes on to verify one way or the other if that circuit alone is causing the problem.

 

[jramsey2008]

Outside 92-94. Inside, 79.

 

[RPR]

Is your power cord from the pedestal getting hot? This heat is may be taxing the campground capability.

 

[jramsey2008]

The power cord temp is fine. These temps in Florida are normal for this time of year and we didn’t experience anything like this last year.

 

[craigav]

I would check and make sure you are not encountering low voltage. ~CA

 

[Jerry713]

I had this problem once and ended up having to replace the power distribution/converter system.

I wouldn't step over a dollar to try and save a dime here. You could be looking at a fire hazard. Might be worth 120 bucks or so having a mobile RV tech check it out if you're not sure what the issue is.

I've seen one burn to the ground because of some sort of electrical issue with the power distribution system.

 

[JimD]

Current flowing through a resistance will generate heat. If there is nothing running on a breaker it can not generate any heat. Therefore the heat must be coming from the high current draw of the AC.

I am not familiar with your power distribution center but can only surmise as to how it is set up. I would make sure the buss bar the breaker is connected to is bright and shiny where the breaker grabs it. Same thing for the main breaker(s) on the panel. If that is loose or corroded it will generate heat which will saturate the internals of the center. The current will be flowing in from the power line, through the main breaker(s), through the buss bar, and then through the AC breaker. Any resistance in that circuit could cause heat.

Also, make sure the neutral connections are all tight. The return is often overlooked in electrical problems.

With the center cool before you energize the AC, try turning on the AC while trying to see where the heat is coming from before everything is hot.

I agree with all that say this could be a dangerous situation.

 

[jramsey2008]

Follow-up on A/C breaker tripping

I had an RV A/C technician out to test the system. The A/C pulls 17 amps on a 20 amp circuit. Nothing else out of the ordinary was found, other than he questioned why the inverter fan appeared inoperable. With the heat spell we've been having, continuous running of the A/C was viewed as the cause of the circuit breaker heating up and causing it to trip, i.e., the circuit is not robust enough to handle continuous operation over a long stretch of time. Using a small portable fan to cool the breakers works and was considered by the technician to be a reasonable solution during the heat wave.

 

[craigav]

I had an RV A/C technician out to test the system. The A/C pulls 17 amps on a 20 amp circuit. Nothing else out of the ordinary was found, other than he questioned why the inverter fan appeared inoperable. With the heat spell we've been having, continuous running of the A/C was viewed as the cause of the circuit breaker heating up and causing it to trip, i.e., the circuit is not robust enough to handle continuous operation over a long stretch of time. Using a small portable fan to cool the breakers works and was considered by the technician to be a reasonable solution during the heat wave.

Earlier you mentioned the ambient temp outside was in the low to mid 90's, did the A/C technician tell you that pulling 17a was normal for your A/C? I don't know which A/C you have, however it is not normal to pull that many amps for a 15k btu A/C, in fact a 20a breaker is designed to trip at 80% of its rated load for a continuous load which is 3 hours. In other words, a 20a breaker will trip at anything above 16a with time, and the time is less and less as you exceed the 16a (80%). My 15k A/C is older than yours, likely less efficient and runs 14~15a even with temps 105+, so something is still not right with your setup, could be low voltage as I mentioned earlier, did the tech tell you what the voltage was when the A/C is running and pulling 17a? ~CA

 

[jramsey2008]

Earlier you mentioned the ambient temp outside was in the low to mid 90's, did the A/C technician tell you that pulling 17a was normal for your A/C? I don't know which A/C you have, however it is not normal to pull that many amps for a 15k btu A/C, in fact a 20a breaker is designed to trip at 80% of its rated load for a continuous load which is 3 hours. In other words, a 20a breaker will trip at anything above 16a with time, and the time is less and less as you exceed the 16a (80%). My 15k A/C is older than yours, likely less efficient and runs 14~15a even with temps 105+, so something is still not right with your setup, could be low voltage as I mentioned earlier, did the tech tell you what the voltage was when the A/C is running and pulling 17a? ~CA

The tech didn’t think 17 amps was a problem, but you’re probably right. We stayed in Yuma a couple years back and ran the A/C nonstop during 105 degree outside temperature without tripping the breaker (the A/C wasn’t up to the task either, as the inside temp rose into the low 90s). He didn’t report the voltage, but I would be surprised if it was low, as we’re in a big resort operating at 1/3 occupancy and we have our own connection to the electric company. I’m guessing the unit is worn out and needs to be replaced.

 

[craigav]

The tech didn’t think 17 amps was a problem, but you’re probably right. We stayed in Yuma a couple years back and ran the A/C nonstop during 105 degree outside temperature without tripping the breaker (the A/C wasn’t up to the task either, as the inside temp rose into the low 90s). He didn’t report the voltage, but I would be surprised if it was low, as we’re in a big resort operating at 1/3 occupancy and we have our own connection to the electric company. I’m guessing the unit is worn out and needs to be replaced.

The compressor pulling 17 amp is a bit high for sure. The most common reason for an A/C compressor to be pulling higher amps than expected (other than low voltage, or very dirty coils, etc) is that the "RUN" capacitor needs to be replaced. When a "START" capacitor fails it is easy to determine as the A/C will not start, however when a run capacitor goes bad, the result is that the unit will pull higher amps if it is able to continue running. If the Tech didn't believe 17amps was a concern, I doubt he would have pulled and tested the capacitors, however imo he should have done so.

Here is one link just for fyi (not sure if it is for your A/C) but notice in the description:
If your run capacitor goes bad, the motor can turn on but the running amperage will be higher than normal, causing the motor to run hot and have a short life expectancy.

https://www.rvupgradestore.com/Coleman-Mach-Run-Capacitor-14995741-p/70-4144.htm

 

[jramsey2008]

Thanks for the capacitor info. Sure beats the price of a new A/C if that’s the issue. BTW, our surge protector at the post indicates 124V and 17-18 amps. I’ll look into what it would take for me to replace the capacitor. If too involved I’ll get the tech back out to do it. Thanks again.

 

[craigav]

Thanks for the capacitor info. Sure beats the price of a new A/C if that’s the issue. BTW, our surge protector at the post indicates 124V and 17-18 amps. I’ll look into what it would take for me to replace the capacitor. If too involved I’ll get the tech back out to do it. Thanks again.

A word of CAUTION to share is that a capacitor can contain a lot of electricity in it even after the power is off, you should use an insulated screwdriver across the capacitor terminals to short out the capacitor's terminals in order to remove any residual electricity stored in it prior to touching any of the terminals on the capacitor. Other than that, it is relatively easy to replace.

The voltage you referenced is fine as you suspected earlier.

One other thought, is that if the entire RV is pulling 17~18 amps, then maybe the A/C is pulling less than 17a as usually a few amps are flowing to the converter and other items even when everything else appears to be turned off.

So if you had 14~15a going to the A/C and 3~4a elsewhere, that wouldn't be uncommon. But if the A/C by itself is pulling 17~18a then that would be more than expected where replacing the run capacitor should lower the A/C compressor's amp draw and will lower the running amp draw if the run capacitor is bad. ~CA

 

[Wireman-JAY]

I would be troubleshooting why the cooling fan isn't working.

 

[craigav]

I would be troubleshooting why the cooling fan isn't working.

Keep in mind that the cooling fan is for the charge\power converter, not for the 120v breaker panel even though it is in the same area. The cooling fan is thermostatically controlled by the converter's operating temp, not the breakers operating temp. ~CA

 

[JOLOOOTE]

Ac on 20 ???

I know the connections on the A/C breaker (20/15 combo) are tight, as replacing that breaker was my first step. When the new breaker tripped I noticed that all were hot. I’ll be replacing the single 15 amp breaker tomorrow (it seemed to be the hottest, though that could just be my imagination), and will recheck all connections then.

I've been rving since 1971. In my early days I burned out several AC compressors trying to run them on a 20 amp circuit. If you're going to insist on attempting to run an AC on only 20 amps you have to monitor your ac voltage at any Outlet inside your rv. If the voltage goes below 106 volts ac the AC compressor is drawing lots and lots of current and overheating and will eventually fail as is the entire 20 amp circuit.