roof A/C TRIPS 20 AMP BREAKER

[Britches]

WORKING ON ROOF A/C it runs and is cold for about 15 to 20 minutes and then it trips the 20amp breaker that it is connected to. trailer breaker box. I was thinking possibly I should use a 30 amp breaker. Do you have any suggestions

[ksg5000]

Britches wrote:
this afternoon I went through and checked the wires and the breakers it is all good. the electric pedestal in rv park is brand new. So all looks good. A/C now does not turn on it just hums. fan and a/c positions js maybe time for window a/c huh?ust hummm

New pedestal doesn't mean much. Have you tested the pedestal or asked the park to test the pedestal? Have you asked whether any other RV units in the area are experiencing similar problems? On a hot day the park may not have enough power to power everyone's air conditioner and if your on the tail end of the power supply you maybe getting bumped off.

Failure to start up is usually associated with not enough power, bad starting capacitor, or failing compressor. You should also note that when your air conditioner turns off you won't be able to immediately restart it because the head pressure in the compressor will be too high - let it sit for at least 5 minutes.

Have you gotten up top to examine the capacitors? As rigs age it's common for air conditioners to require more power to start up - in my older rig I replaced the original start capacitor with a hard start capacitor which provided the additional power necessary to resolve my start up issue.

Lastly - have you tried turning all the other stuff that uses electricity off when trying to run your AC - converter, fridge, hot water heater etc?

[budwich]

Britches wrote:
this afternoon I went through and checked the wires and the breakers it is all good. the electric pedestal in rv park is brand new. So all looks good. A/C now does not turn on it just hums. fan and a/c positions js maybe time for window a/c huh?ust hummm

likely problem is the starting capacitor is gone. Could be that the compressor has seized but less likely. The cheap fix would be the capacitor but the replacement window conditioner might get your there (cooler) faster.... 🙂

[Heiny57]

Keith099 wrote:
Better yet, if you live in a warm climate, put the electric water heater on a separate 120v 10/3 SO cord. Plug that into the park's 20A receptacle. Been doing that for years.

13-15A draw from AC, 11-12A from water heater, 3-4A from fridge, 1A from 12v converter. You will definitely see problems at that point.

Also helps prevent me from burning up water heating element with extra step of plugging in the cord for that.

My TT has 30A service with all the above plus a 120V mini fridge in the front. I put the water heater, mini fridge, and one interior power outlet for running a space heater all on a separate 30A single-phase panel. Every circuit is separately and appropriately breaker protected.

Also, carry a male 50A to female 30A adapter with you. Some sites will have worn out or weak 30A service due to repeated overloading.

That sounds like great fix's. Could you post some pics of how you did this? Is your extra cord removable?

[Britches]

this afternoon I went through and checked the wires and the breakers it is all good. the electric pedestal in rv park is brand new. So all looks good. A/C now does not turn on it just hums. fan and a/c positions js maybe time for window a/c huh?ust hummm

[Keith099]

Better yet, if you live in a warm climate, put the electric water heater on a separate 120v 10/3 SO cord. Plug that into the park's 20A receptacle. Been doing that for years.

13-15A draw from AC, 11-12A from water heater, 3-4A from fridge, 1A from 12v converter. You will definitely see problems at that point.

Also helps prevent me from burning up water heating element with extra step of plugging in the cord for that.

My TT has 30A service with all the above plus a 120V mini fridge in the front. I put the water heater, mini fridge, and one interior power outlet for running a space heater all on a separate 30A single-phase panel. Every circuit is separately and appropriately breaker protected.

Also, carry a male 50A to female 30A adapter with you. Some sites will have worn out or weak 30A service due to repeated overloading.

[Golden_HVAC]

Britches wrote:
thank you all for your info. The power cord is 25ft. plugged into 30amp at rv park
this trailer in 30amp. I cleaned the filters and gently the fins checked the wiring and connections. I turn on the a/c and it takes right off and blows cold air for 15 min. then trips the inside breaker 20amp that is a/c only. I will go test the volts to see if they are 109 or better by the way the main is 30/15 is this adequate

Hi,

It is common for people in parks with only 30 amp power connections on the post to complain about low voltage, and this caused high motor amperage on the A/C unit, especially when 'everyone' in the park is running the A/C units. This caused the power at the distribution panels to drop to un-acceptable low voltage, and then your unit has only 105V or less to work with.

You can get a 'kill-a-watt' at Amazon.com

You can leave that type of meter plugged into a receptacle, (I keep one in my kitchen receptacle) and monitor voltage. If it is running 115 - 120, I basically ignore it most of the trip. But on a hot day, if it dips below 110 volts, I will keep a close eye on it, and shut off my A/C if below 105 volts. Actually at 110 volts, I will plug in my 12 voltage booster.

If you happen to have a 50 to 30 amp adapter, check to see if you can use that, and plug into the 50 amp circuit breaker. Normally the campground 50 amp receptacle is in much better shape, and less voltage drop across it.

Also check the 30 amp plug, and see if it is warm. If the campground plug is worn out, or has been overheated in the past, the brass inside the plug will not hold onto your trailer RV power cord tightly, and can cause a voltage drop there, as well as overheat the plug on the trailer wiring. So if it feels really warm, or hot like a coffee cup, stop using your A/C unit. Ask for another site (that will probably also have a worn out plug) and ask them to replace that receptacle before it catches fire.

If you have a 20 amp to 30 amp adapter, you might be able to use that - but will only be able to run the A/C and perhaps something with a really small load, such as the TV set or laptop charger.

Also regardless of everything else, change the refrigerator to gas on warm days. It will take 3 amps off the electric cord loads, and also provide 40% more cooling capacity than running on electric.

And if you have a electric element on your water heater, shut that off too, you will have better voltage as a result.

Have fun camping!

Fred.

[enblethen]

The 30/15 is a split breaker. The 30 is the main and the 15 is a branch circuit.
I would check the neutral(white) wires in the back of the 120 volt distribution panel. A loose connection causes increase in resistance and voltage drop.
Pick up some electrical grease from your local hardware store.
Disconnect from electrical source
Disconnect each of the neutrals one at a time and inspect for dark coloration of the wire.
Apply a liberal amount of the electrical grease(de-oxidation) to the conductors.
Re-connect wire.
Do this to your branch wires and incoming wires that are attached to the breakers.
DO ONE AT A TIME!
Don't forget to disconnect from electrical supply!

[ksg5000]

Have you tried running the AC on your generator -that may help isolate the problem.

If the unit runs fine on generator then you have an issue with shore power ... source, extension cord etc.

When I have AC issues I start with cleaning the filters and both the Condenser and Evaporator coils. The Evaporator coils are often ignored because they are under a metal cover on the front of the AC unit - you need to get up top and remove the housing and a number of sheet metal screws to get access. Common problem - use Google to get info on how to clean the Evaporator coil. Cleaning all the coils will help reduce electric load on unit.

If issue continues after cleaning .. then look at the capacitors - if they smell or bulge then replace. If your rigs old replace because they are dirt cheap. If problem continues after replacement of capacitors then it maybe your compressor and the cost of replacing that usually warrants replacement of entire AC.

[budwich]

Possibly a "poor" starting capacitor. On the initial start, the system pressure is likely low / lower and allows the unit to start within the current rating. Probably after a bit, the A/C has cycled off and then attempts to restart. The increase in "head pressure" potentially causes an increase in current required tripping the breaker. Just a guess... as others suggest, try replacing the breaker and see if things change and go from there.

[Britches]

thank you all for your info. The power cord is 25ft. plugged into 30amp at rv park
this trailer in 30amp. I cleaned the filters and gently the fins checked the wiring and connections. I turn on the a/c and it takes right off and blows cold air for 15 min. then trips the inside breaker 20amp that is a/c only. I will go test the volts to see if they are 109 or better by the way the main is 30/15 is this adequate

[rbpru]

Low voltage will cause the AC to draw more current, what size power cord are you using to feed it and how long is it?

Next I would see what the current draw rating is on the AC unit.

If you up the circuit breaker to 30 amps you may be pulling 30 amps through wires that are only rated for 20 amps. Not a good idea.

[donn0128]

Weak breakers will trip when at or near full capacity. Replacing it with a 30A breaker is dangerous. You then have no protection of the undersized wiring with the resulting possability of fire. 20A is really borderline for a AC unit, especially if it a 15K AC unit. Replace the breaker with the same size then refrain from using the AC on 20A.

[Bigbird65]

Could be a weak breaker. The head pressure may be high. Is the inlet filter clean?