AC tripping breaker

[Karma eh]

I have a Southwind diesel motorhome which is a 30 amp system. When running the Coleman TSR series AC on a 30 amp park hook up it will trip my inside breaker after 30 - 60 minutes. There are 2 ac units with a switch that selects front or back, not both at once and either unit will trip the breaker.
Is it possible that the breaker is somewhat defective?
Not sure where to turn at his point. Do I look into installing a hard start capacitor (cheaper way to go instead of the soft start versions).
Thanks for any advice or help.

 

[Oldgator73]

The AC runs for 30-60 minutes so the starting amps aren’t tripping the breaker. Is your 30 amp cord getting hot or the breaker getting hot? Does the pedalstle have a 50 amp receptacl? If so get a 30-50 amp dog one and try the 50 amp receptacl.

 

[Ex-Calif]

What size is the A/C? I can see one unit drawing 15 amps but that's well below the 30amp breaker.

You aren't reporting that the pedestal breaker is tripping so you are probably staying below 30 amps.

My guess is as yours that the breaker may be faulty/weak. It's a very cheap troubleshooting option.

Are you running anything else at the time? Coffee pots, toasters and electric water heater draw a ton.

In my coach I can have 13,500 btu A/C, water heater, microwave, Keurig type coffee maker, toaster oven and air fryer.

I can only pick two at a time or I blow my 30 amp breaker.

 

[Karma eh]

We only have the fridge and a small fan running. I believe they are 13,500 btu ac units.
I will switch out our breaker to see if that works...it is pretty old. I think original from new. The coach is 1995.

 

[Oldgator73]

Sorry, didn’t read your post correctly. Thought the pedestal breaker was tripping.

 

[Karma eh]

Only have 30 amp at the post

 

[Kirk]

Is it possible that the breaker is somewhat defective?

Circuit breakers do get old and can fail due to use or age. If that is the original circuit breaker, to fail in 27 years is not unexpected. I would replace it first. It it you main breaker that is tripping but the one for the air conditioner is not tripping? If so it is the total of your loads that is causing the problem and not just the air conditioner. I suspect that the breaker for the air conditioner is a 20a breaker.

 

[Karma eh]

Circuit breakers do get old and can fail due to use or age. If that is the original circuit breaker, to fail in 27 years is not unexpected. I would replace it first. It it you main breaker that is tripping but the one for the air conditioner is not tripping? If so it is the total of your loads that is causing the problem and not just the air conditioner. I suspect that the breaker for the air conditioner is

 

[Karma eh]

Circuit breakers do get old and can fail due to use or age. If that is the original circuit breaker, to fail in 27 years is not unexpected. I would replace it first. It it you main breaker that is tripping but the one for the air conditioner is not tripping? If so it is the total of your loads that is causing the problem and not just the air conditioner. I suspect that the breaker for the air conditioner is a 20a breaker.

Thanks for the input Kirk. It is the ac breaker that is tripping. A quick question ....could the convertor itself go bad ? We do hear a slight higher pitch sound coming from it.

 

[Old_Crow]

Thanks for the input Kirk. It is the ac breaker that is tripping. A quick question ....could the convertor itself go bad ? We do hear a slight higher pitch sound coming from it.

They can and do go bad. When mine went bad, it did indeed trip the breaker. I unplugged it and the breaker quit tripping. Thanks to Prime, I had one the next morning.

 

[Kirk]

....could the convertor itself go bad ?

It could but it probably isn't supplied by the circuit breaker that supplies your air conditioner. The converter takes 120V from shore power or an onboard generator and converts that from 120V-alternating current into 12V-direct current and that has nothing to do with the air conditioner. In most RVs that converter has a circuit breaker. Because the step in voltage also means a steip in current, for your converter to be supplying 50A at 12V to the battery, it would only require 5A at 120V plus a small amount of line loss so perhaps a total of 5.5A fron the supply.

The noise that you hear is probably from the cooling fan in the converter and those do sometimes fail or make noise because they have become loose and now vibrate with nothing else wrong.

 

[Mark_K5LXP]

An inexpensive clamp on meter will answer the question - is the circuit overloaded? An absorption fridge draws about 400W, a converter at full tilt could be 500W. Have a water heater kick on, warm up lunch in a microwave, DW plugs in a hair curler, etc and you have the makings for an overload when up to half of the system capacity is soaked up with the A/C. Not saying it can't be a breaker but it's entirely plausible some "silent" loads may be present.

Mark B.
Albuquerque, NM