Breaker size in Motorhome

[PirateCamper]

OK, I pulled my breaker out. It's a single pole,tandem 15/20 amp breaker. The 13,500 BTU Atwood roof mount A/C is wired into the 15 amp side. The 120v outlets are wired into the 20 amp side. The local hardware store only had a 20/20 tandem breaker. I've read the internet for the last two hours and still have no clear idea if I can use this breaker or not. Several people say the 15 amp breaker on the A/C can be moved up to a 20 amp due to the peak at start up. Others say leave it at 15 amps and let it flip.

The 15 amp side tripped a lot during a trip over the Labor Day weekend during the day and on the trip back home. So much so, we shut it down and suffered the heat.

The geny voltage is OK. I think the breaker is just old, BUT I don't to set the RV on fire! HELP!

[georgiawoody]

Breakers trip for reason you must check out ac georgiawoody

[paz]

If your rig had a 15A breaker, there's a good chance your wire is also sized for 15A (14 gauge). DO NOT use a larger breaker than your wire is sized for!

You say the breaker is old which may be one reason it is tripping prematurely. One way to check is to replace it, but if you can't find a 15/20A breaker, replace it with a 15/15A NOT a 20/20. That will reduce how much you can have plugged into your electrical outlets a little bit, but at least it won't start a fire. Another option if you have an empty slot in your electrical box is to add a 15A breaker and move the AC wire to the new breaker. Leave the 15A side of the existing breaker empty and leave the electrical outlets connected to the 20A side.

Another reason for your breaker tripping is your compressor may be working too hard. One possible reason it is working too hard (other than the fact it is hot outside) is dirty coils. Both the evaporator and condenser coils need to be cleaned periodically as we found out this past summer. The condenser coils are shown below.

[PirateCamper]

Looked like rain all day, so I waited, but none. As soon as I get involved in the RV work, here it comes. Better luck tomorrow.

During the Labor Day trip, the A/C worked great on the way down to Myrtle Beach running on the generator, 4k Onan, It worked great both nights. Breaker tripped a couple of times on Saturday, so we took our Parrots inside my sons house and shut it all down.
That Sunday, it ran fine until it got up to around 95 & high humidity, so it started tripping every few minutes. So we did the 150 mile trip back home in the heat.

I'll pull the case and check the A/C for debris. I won't use the 20/20 breaker. I forgot about the wire size limitation. Glad I asked. I don't know if this is the original breaker or not, but, better safe than Rv'less!

Thanks!

[bluepill]

First, we should clarify the term twin circuit breaker, which is a standard full size (single-pole frame) circuit breaker that incorporates two overcurrent devices, each switched independently. The overcurrent devices connect to the same ungrounded phase bus in the panelboard. Twin circuit breakers are typically limited to 120/240 volt, 15 and 20 amperes, and 10,000 amperes interrupting capacity. Twin circuit breakers are also known as dual, tandem, piggyback and two-pole thin. As an aside, there are single-pole overcurrent devices that are half the width of a standard full size single-pole circuit breaker. The single-pole devices are known as half size and single-pole thin.

Are both poles (The 15 and the 20) tied together at the handles or the body? If not, and if they are standard design, you can just replace the 15.

If they are tied together, possibly you can install 2 new half size units.

[PirateCamper]

Originally Posted by bluepill

First, we should clarify the term twin circuit breaker, which is a standard full size (single-pole frame) circuit breaker that incorporates two overcurrent devices, each switched independently. The overcurrent devices connect to the same ungrounded phase bus in the panelboard. Twin circuit breakers are typically limited to 120/240 volt, 15 and 20 amperes, and 10,000 amperes interrupting capacity. Twin circuit breakers are also known as dual, tandem, piggyback and two-pole thin. As an aside, there are single-pole overcurrent devices that are half the width of a standard full size single-pole circuit breaker. The single-pole devices are known as half size and single-pole thin.

Are both poles (The 15 and the 20) tied together at the handles or the body? If not, and if they are standard design, you can just replace the 15.

If they are tied together, possibly you can install 2 new half size units.

They are tied together at the body. I located a local source for a replacement 15/20. I'll get it tomorrow. I'll pull the A/C covers and clean it out good and then drop in the new breaker. Fingers crossed.

I put the irv2 APP on my iPhone, so now when I get an answer, I know immediately.

Thanks for all the help!

[paz]

Originally Posted by PirateCamper

They are tied together at the body. I located a local source for a replacement 15/20. I'll get it tomorrow. I'll pull the A/C covers and clean it out good and then drop in the new breaker. Fingers crossed.

I put the irv2 APP on my iPhone, so now when I get an answer, I know immediately.

Thanks for all the help!

Great! Keep us posted.

Bluepill's idea about getting 2 half-size breakers (one 15 and one 20) was a good one if you hadn't been able to find a 15/20A combo.

[wa8yxm]

My position.. MOST Air conditioners are on a 20 amp line.. So why yours is on a 15, I very simply do not know.

WHAT SIZE WIRE is screwd down on that breaker.

IF the wire is 14ga.. Stick with 15 amp.

If it's 12ga you can "upgrade"

The fact that it is a tandum breaker suggests after market modification.

Note, on the outlets side.. Same thing 14ga wire gets 15 amp breaker, 20 needs a 12ga.

[PirateCamper]

I'll measure them and see. Thanks!

Originally Posted by wa8yxm

My position.. MOST Air conditioners are on a 20 amp line.. So why yours is on a 15, I very simply do not know.

WHAT SIZE WIRE is screwd down on that breaker.

IF the wire is 14ga.. Stick with 15 amp.

If it's 12ga you can "upgrade"

The fact that it is a tandum breaker suggests after market modification.

Note, on the outlets side.. Same thing 14ga wire gets 15 amp breaker, 20 needs a 12ga.

[GuitarLefty]

If you have no electrical experience I would call around and find an electrician with RV experience. If you have a bit of expertise you could use an amp meter to determine the load and how many amps are being pulled at start up and how many are being pulled continually.

[PirateCamper]

I found out I have a Coleman Mach A/C. I pulled the top cover and the rear condenser was clean inside and out. I pulled the sheet metal cover off the top, front and found black insulation, so I put it all back. I pulled the cover off the inside and found a light coating of dust on the front condenser. I’ll worry about that later. Read on.
I found the single pole, tandem 15/20 amp circuit breaker at Lowe’s. Along with a new auto ranging multimeter that also reads Hertz and temperature. $35 Sweet!

Anyway, I switched out the breaker. Every single screw in the transformer was loose! Some a ¼ turn, others were a ½ turn. Fixed that. While checking the Onan, I found a broken yellow wire that had been crimp connected to another yellow wire. It was the remote switch from inside that had stopped working on the Labor Day trip. Whew, I almost ordered a new switch. Fixed that. So, I start the Onan, let it warm up for about ten minutes. The voltage at the breakers was 131 volts. Just what the Onan should be at with no load by the manual. I set the A/C to max cool at lowest setting. At start, it drew the voltage down to 127 volts and stayed there. Well, I think this is my problem, over voltage adjust the Onan.

While lying in the floor I see a 120 volt light switch on the side of the dinette seat, this is the water heater I was told. I flip it on and the Onan slows down… a lot. The breakers now read 116 volts. So, if this will pull the Onan down enough to not overload the breakers, I figure I can run it this way if it will work. So, I checked a few more things, the A/C was putting out 60 degree air and it was 80 outside. Everything seemed OK. Then, after about ten minutes, the main 30 amp breaker flips. So, I can’t run the water heater and the A/C together. If I run the A/C alone, it over heats the breakers, If I lower the Onan, it may not run everything else.

The former owners used Shoreline power most of the time. Running the Onan very little.
So, where do I go now? I just want to run the A/C while we drive, off the Onan and while we boon dock.

I guess I could tone down the Onan and roll the dice. Any help is appreciated. Thanks in advance!

[PirateCamper]

All three of the breakers in my transformer are tandem, single pole. A 30/20, a 15/20 and a 15/15. The 30 is the main. The 20 is the dinette outlets. The 15 is the A/C. The 20 is the GFI outlet, the next 15 is the Microwave and the last 15 is the rear galley.

[GuitarLefty]

Measuring voltage is different than measuring amperes (amps) The easiest way to measure amps is with an amp meter with clamp, clamp around the hot wire( shield included) and it will read your amp draw. Interesting that your trouble happens after several minutes of being on. Sounds to me that the trouble is with the generator (very amateur guess) interested to know if everything works normally on shore power.

[PirateCamper]

The prongs of the shore power plug are toasted and the rubber is melted on the main plug as well as the extension plug. The extension is the same size as the main but, half the length. I figure it could be due to near max amps pulled with a poor plug on the pole. I just want to be able to run the Onan and A/C while driving.

I think the Florida owner, previous to the owner I purchased from, installed a water heater that must run alone. I guess they forgot that this coach has only 30 Amps to divide among its toys!

I guess I could back down the output of the Onan to run the A/C at 115 Volts and see what that does. I'm aware I can only run one major thing at a time. Since the engine A/C is non functional, and the doghouse is like a volcano until I can re-cover it with some space shuttle tiles... I'd like to keep the sweat out of my eyes and not roast my Parrots alive!

Going to borrow an Amp meter this week and the truth will set me free! LoL

Thanks for the help, keep it coming.