Blowing 30AMP breaker blowing

[rcharrette]

Hi all, we have a 2014 Dutchman Kodiak 240BHSL. We've had it for 2 years now and have never had this problem. We arrived at a new KOA campground yesterday (opened in May) and we are at a site that is rated for 30AMP service (no 50 amp) and our plug is 30AMP. Today we had the AC running the TV on and then my wife put something in the microwave. As soon as she did that the 30AMP breaker tripped inside the camper. The breaker on the pole outside was fine, it did not trip.

I'm not sure where the problem is because I know we've run all 3 of these in the past at once. My initial thought was the problem was on the campground side and that it was not actually a problem - the site only runs 30AMP. However I would think the breaker would trip outside(campground pole), not inside the camper if that's the case?

So looking for some direction on this. It is under warranty still so I can take it in if a problem exists but again, if it's a 30AMP site maybe that's the issue??

 

Thanks,

Randy

[hemsteadc]

I'm surprised you could ever run the MW at the same time with the AC (if AC means air). My guess is that this CG's voltage is weak, causing a larger amp draw. Get out your trusty voltmeter and take some measurements.

[trailertraveler]

The AC and the microwave will put the load pretty close to 30amps. Was the refrigerator on electric? How about the water heater, was that on electric? The converter will draw a little to power all the DC circuit boards. If the battery charger came on even to float, that may be a couple amps. If any of the things I've mentioned drew power while the AC and microwave were on, I think it is quite possible that you exceeded 30amps.

[docj]

We've been on 30A all summer and had to ask the CG owner to replace the breaker on the pedestal because it was tripping too easily. Once he replaced it we've had far fewer problems. Fortunately, on PEI we rarely need the A/C and my wife knows that she can only run 2 "major appliances" at a time. For us the list of majors is: microwave/convection, countertop Breville, clothes dryer, electric water heater, pressure cooker. We have a hydronic heating system that can provide hot water so we turn the hot water tank off if we need to wash dishes while things are cooking.

 

One additional thing I've had to allow for, however, is the current draw of the converter/charger side of our Magnum MS2800. Even with it set for 30A shore power, if the inverter has run for a few minutes because the breaker tripped and my SurgeGuard's delay feature takes several minutes to restore it, then the charger may go to full charge which can easily be ~100A DC. That's like having another "major appliance" running and can cause the breaker to trip again if you don't allow for it.

[TXiceman]

Put the frig on gas and the water heater on gas. You will help the power draw a bit and may be able to run the A/C and microwave at the same time.

 

Get a volt meter and check your voltage inside the RV when you have the A/C Running. You need a minimum of 108 volts for the A/C to operate.

 

The A/C is an inductive motor and when the voltage drops, the amps will rise to produce the same power. In the summer, the power grid in a park is taxed to the limits and the voltage will drop and the amps will go up.

 

Ken

[rcharrette]

Thanks for all the replies. Yes, Fridge and water heater were also on shore power at the same time. Didn't think about that.......... Looks like operator error on my part. That's good news though as it's never fun to take this into the shop!

[oldjohnt]

Indeed, Microwave and AC alone (subject to size and watts) are crowding a 30 amp breakers limits, so if you throw in a fridge running on electric plus a water heater on electric its TRIP THE BREAKER TIME.

 

Been there done that as many RV owners have Im sure

 

John T

[Kirk W]

First let's do a little bit of math to think this through. An RV air conditioner will use between 8a and 13.5a, depending upon how large the cooling capacity is, if we assume it is in good condition, which an a/c only a year old most likely is. The microwave load will also draw current depending upon the power rating of the unit. A 700 watt will need about 6a. One that is 1100 watts needs a bit more than 9a. The very largest of microwaves need about 13a but smaller ones are more common so let's use a nominal figure of 9a.

 

An RV refrigerator when calling for cooling has an element that if fused for 5a and if a two door model it may have two of those, for a total of 10a maximum, but since your fuse isn't blowing you should probably use about 3a per element. The TV most likely uses no more than 5a once it is operating.

 

That means that in all probability you should be able to run all of these at the same time, if you have proper shore power voltage. Adding these all up, you come to a typical total of 27a and your converter may well be using an amp or two as well. It is pretty safe to guess that you are pushing close to 25a and possibly close to the 30a limit. Most 120v circuit breakers are not designed to carry their maximum rated load constantly for a very long period but will actually allow somewhat more for very short periods.

 

Where the rub comes with loads as close to the limit as you have is that if the shore power is not 120V but something lower as is very common in older RV parks, then an ac powered motor will increase the current it draws in an effort to keep things working. One of the negative features of an ac electric motor is that when electricity voltage falls, current increases, exactly the opposite of the situation with restive loads, like an electric heater. The result is that if your power was in the range of 108V where it should be 120V, that might likely be enough to cause the motors in your air conditioner to go up to 15a or more and that would then trip the RV's 30a circuit breaker. Since you have a 30a breaker at the pedestal and another in the RV, basically one at each end of the power cord, there would be a race between the two to see which one was going to trip.

 

The loads that you list are very close to the limit of what your power cord is rated to supply and that is the reason for the circuit breaker in the RV, to prevent that cord from overheating to the point of melting. The breaker at the pedestal is actually there to protect the RV park from any problems that you bring with you when you arrive. I highly doubt that you have a problem that any warranty will attempt to do something about.