Shore Power Issue

I have a question and an unsolved problem with tripping breakers that I'm hooked into.  I picked up my new to me MH almost 2 months ago and leave the coach in my side yard plugged into a 20 Amp 115 V receptacle.  Everything has been working fine for these 2 months as long as I only operate 1 A/C unit and the refrigerator.  The inverter / converter is also powered.

This weekend with only one A/C running, it kept tripping the home beaker.  It might take 5 minutes or 2 hours, but it would trip.  So, thinking there may be something else in the house on the same circuit, I got out my Honda 6500 Inverter generator and plugged into the 30 Amp receptacle.  It tripped twice in the first hour and then worked flawlessly for 4 more hours.  I plugged back into the house 20 Amp outlet and it tripped within 5 minutes again.

Any remedies or suggestions as to the cause for this problem?

The only thing that has changed is the outside air temp is up about 15 degrees from what is has been.

On the MH, I've checked to make sure the electric water heater switch is off and block heater switch is off.  Is there anything else that could have been inadvertently turned on that would be robbing available power?

On the MH Onan, all works without any problems at all for as long as I want to keep feeding it fuel.

I am having a 50 amp hookup installed in a couple of weeks.  I tried to get it earlier, but the Power Company (FPL) can't increase my service wire size until the end of the month.  I don't have enough room or capacity in my existing panel to get it done sooner.

Does your coach have an EMS? (electrical management system). If so, what make and model? Is there any chance the second air conditioner is kicking on? Do have a converter and an inverter? These are different devices. Or do you have an inverter with a 12 volt charging section and no stand alone converter? When is the last time you have cleaned your air conditioner coils? Also, check the capacitors on the air conditioner.

kdbgoat said:

Does your coach have an EMS? (electrical management system). If so, what make and model? Is there any chance the second air conditioner is kicking on? Do have a converter and an inverter? These are different devices. Or do you have an inverter with a 12 volt charging section and no stand alone converter? When is the last time you have cleaned your air conditioner coils? Also, check the capacitors on the air conditioner.

Click to expand...

Not sure about the EMS or converter/inverter.  I will check when I get home from work and post what I have.  The second A/C is definitely off. I will also check the filters and coils on both A/C units as I have not checked them at all.

While you have the cover off the top, you should also check the capacitors. If you don't know how, turn the breakers for the units off, short each terminal of the capacitors to ground with a screwdriver or short piece of wire, and take them to an electric motor repair shop. They will probably test them for free.

Well yes. I do have a suggestion... As it turns out.

My Coach has 2 A/c's  Well suddenly one of them was tripping the 20 amp breaker that feeds the unit.. JUST LIKE YOURS. might take 5 minutes, longer, shorter.. I put a clamp on ammeter on the power lead (at the breaker box) and watched it go 13.14.15. ....21 click.

Inspiration struck.  and I went "Topside" (Or as the song is titled: Up On The Roof).

Removed the outer  cover and the inner cover from the condenser (the outside coils) and observed they were clogged with crud.. I had to remove the fan on the Carrier Air V to clean it properly but once I got it all back in one piece,, I checked the meter again 13,13,13----------13 and no CLICK.

NOTE: Where as most RV A/Cs blow (like my carrier they take in air from the sides and BLOW it out the concenser)

COLEMANs SUCK,, (Suck air in through the condenser) this means you do NOT need to remove inner covers.

Since then I've parked under cotton woods a few times, and every time it's back topside and clean the condensers.

Just a couple of thoughts.

Is the power coming from an outdoor outlet?  Most outdoor outlets are GFI protected and often come from a bathroom outlet.
I found this out as I hooked mine up to an outdoor outlet and then used the shower in the bathroom and the circuit breaker tripped.

So the other question is do you know that nothing else is used on that circuit as it's unusual to have one plug on a circuit by itself.

Another thing is many RV's charge the house batteries by default and are on when plugged in.  Then the fridge cycles from time to time
then the AC also cycles time to tome.  IF they all hit at the same time I could see it tripping the breaker.

And one more.  It could be an overly sensitive circuit breaker.  IF you have another 20 amp breaker in the box could you swap it with
the one that keeps tripping?  It's a long shot but possible if your at the edge of 20 amps and the one tripping does it at 18 or 19 amps.

Hope that helps - please report back with what you find.

I know if I plan on used the AC at home I turn off the fridge while the AC is running and unplug anything in my home bathroom.
That works for me.

kdb & John - I THINK you are on to something with the A/C filters and Coils.  I called home and had my wife pull the filters out from the ceiling intake louver.  She sent me a picture of the filters and the units above and they were full of crud.  Cleaning them will be my project when I get home.

Red - I went though all that.  That is why I plugged into my Honda 6500 Inverter generator to make sure there was nothing else on the circuit.  It still tripped.

Here is some help to check capacitors:

https://itstillruns.com/test-rv-air-conditioner-capacitor-7823972.html

I recommend taking pictures of the caps and wiring before you disconnect anything to ensure the wiring goes back correctly.

Ok the inside filters need occasional cleaning as well (By the way I used my A/C for the first time this year... well one of 'em. the other was not needed)

The outside coils up on the roof are the ones that trip the breakers,

here is how it happens
The way the system works is to pressurise the gas this greatly increases the temperature of the gas  Then it forces it through the "Condenser" coils where it sheds nost of that heat to the air passing through the coils. Then the liquid that runs off the condensers still under high pressure is sent through a few things including an "Expansion valve" where it enters the evaporator coils now its very very cold so it absorbs heat from the INDOOR air,

What is happening: If the condenser coils are clogged with crud (IE: Cottonwood "Cotton") air can not move through them and remove the heat to the outside.  So the heat continues to build temperatures rise and pressure goes up and up.  Now the Compressor is the "Heart" of your Air Conditioner. and just like YOUR heart the higher the "Blood Pressure" (Coolant pressure) the harder it works. 

And the harder it works the more power it draws  Till eventually one of two things happens

In the case of the A/C the breaker trips.. preventing the compressor from burning out.

IN the case of YOUR heart.. It's a medical emergency and you have to call someone like me (9-1-1 was my office phone number)  Same thing.

The A/C is a whole lot easier to fix.

Update - I believe cleaning the coils was the correct thing to do.  I only cleaned them from the under side but it seemed to solve the problem for now.  I will get the very nimble SIL to get on the roof and do the top side work this weekend.

With all the plugging and unplugging swapping receptacles and plug in locations, I had the ground prong on the MH 50 Amp cord come apart.  Looking at it, it was only held on by a very small corner, if at all.  I'm sure that could have been part of my problem, especially when it tripped the 30 amp circuit on the inverter generator.  Thoughts?

A bad ground like that shouldn't trip a breaker. It just makes your electrical system dangerous.

I have to disagree somewhat about cleaning the coils and lower/higher electrical loads.  The compressor draws the same power whether coils are dirty or not - it doesn't care.  Maybe the fans works a bit harder if air cannot flow freely, but that is a very small part of the total amp load anyway.  It might be a factor, though, when using a 20A circuit. Whenever the compressor cycles on, the momentary peak power draw probably exceeds what a 20A circuit can supply, but the breaker doesn't trip instantly so the start-up cycle continues. And extra 0.5A might be enough to push it over the edge.

There are other power load factors that are not readily visible. For example, your RV is always producing 12v power for control circuits, gas detectors, and what not, plus battery charging as well. That's not a big 120v load either, but if it happens to be running at 1-2 amps at the moment the a/c compressor starts, the combined draw may be enough to trip a breaker.

BUT...You say it also trips the 30A breaker on the genset? That's a serious amount of power and leads me to think there is some other 120v power draw that you are overlooking. It may be on a thermostat, so it cycles on/off and only once in awhile engages at the same time the a/c is operating.

I've worked as an HVAC service technician in a past life, and have to disagree with you on this one Gary.
Don't take my word for it:

https://www.achrnews.com/articles/84466-restricted-airflow-a-common-culprit

kdbgoat said:

A bad ground like that shouldn't trip a breaker. It just makes your electrical system dangerous.

Click to expand...

Ditto with one exception.. On your 30 amp Inverter Generator ... That pin may well be N/C (NOT Connected)

The exception is if the GREEN wire inside the plug flops around and makes contact with teh black one.. Then it will trip the breaker and fast if there is any point of bonding .

Fact: One of the reasons I do not always trust professionals.

Back in the days of sticks and blocks.. I had my HEVAC updated from window air to centeral air (Along with a more efficient furnace)  The electrician hooking up the A/C hooked the Black wire to the Green screw.. For some reason it kept blowing fuses.

We discovered it about a month later (took that long for the weather to get warm enough) when we went to charge the system and it would not take power... The Charge technician was also an electrician and fixed it,, But I have a feeling he needed a new pair of shoes after he got back to the shop and had a "Chat" with the original electrician.. Who need a proctologist to remove a shoe........