Well this is just common sense!

[TURBS]

And a perfect example of why you shouldn't run your a/c on 15 amp household service.

RV technician uncovers new Dometic fire source | RV Daily Report




2015 Columbus 320RS
2008 2500HD Duramax
2015 nights camped "34"
2016 nights camped "22"

[jchiar]

Wow great read. Who'd of thought?

[jchiar]

I admit I've run the AC alone with those adapters. But only on a 20Amp outlet. And never with the Fridge on.

[TURBS]

Last night in the heat and humidity my 15k was drawing 18 amps
Nothing else on electric except the constant converter which was drawing 2 amps.


2015 Columbus 320RS
2008 2500HD Duramax
2015 nights camped "34"
2016 nights camped "22"

[jchiar]

How can I figure out how much kilo watts my AC is?

[jeff64]

Volts x Amps = Watts, 1 Kw = 1000W

[jchiar]

Understood. P=IxE. What did measure the current with?

[myredracer]

I have to disagree with the assessment of the RV tech. RV techs are not engineers or electricians and are not qualified to make those sorts of assessments.

The condition of the blades on the adapter in the photo would indicate continual plugging in with the power still on. A converter has a momentary inrush current that causes pitting on the plug and receptacle/connector surfaces which in turn attracts dirt. Over time with repeated plugging in live, the surfaces get more and more pitted causing more dirt buildup and resistance that eventually causes heat and a meltdown (or worse). This happens a lot and I've seen many photos of this. I've seen some fairly new pedestals that actually now have a label on them saying to shut the power off before plugging in.

AC unit manufacturers specs. state that min. #12 gauge wire should be used along with a 20 amp breaker. Running current is in the 15 amp range for a 13.5 BTU AC unit and a Coleman Mach 3 for ex. is 15.3 amps. Starting inrush current (locked rotor current) for this AC is listed as 63.0 amps. A 15 amp adapter is not designed or approved to be running more than 15 amp on a continuous basis or to have high inrush currents. So if you are using a 15 amp adapter and running an AC unit, that's asking for it to become overheated. Couple this with the converter inrush current and there will eventually be damage and enough heat to cause melting (or worse). If you ask me, those 15 amp adapters should be banned and be rated for 20 amp or 15/20 amp circuits. The puck style adapters are much more likely to be damaged from overheating compared to a pigtail adapter due to the close proximity of contact surfaces.

The article states the Dometic refrigerator control boards will melt down as the current seeks a new neutral connection, the technician explained. That causes the electricity to jump to the earth ground connected to the chassis via the incoming shore earth ground. This makes no sense.

Who knows - maybe they are even trying to divert attention and blame to another source?

Just my 2 cents...

[Mr Havercamp]

Originally Posted by myredracer

The article states the Dometic refrigerator control boards will melt down as the current seeks a new neutral connection, the technician explained. That causes the electricity to jump to the earth ground connected to the chassis via the incoming shore earth ground. This makes no sense.

X2

Not only that. Reading between the lines some supposed "tech" at a dealer used that 15 amp adapter while working on someones rig. He discovered this while operating both the Fridge and AC while using that adapter and who knows what else on the rig, the converter for sure, did he fire up the microwave and heat up his lunch?

One of the comments to that article may say it best.......

"Trying to understand why this article insinuates that this is a Dometic refrigerator flaw. The orientation of these cheap adapters caused the trailer power cord to be plugged in “upside down” resulting in poor connection in the first place. Why any tech would be troubleshooting with one of these adapters negates the rule of having proper power before diagnosing an appliance. Not just refrigerators are impacted by this scenario. Why any 15 or 20 amp shop outlet is not a gfi is an electrical code question.
We as dealers and technicians should be educating our customers in the proper use of the systems on their RV and not providing fodder for class action lawsuits.
My $.002"

[TURBS]

Originally Posted by jchiar

Understood. P=IxE. What did measure the current with?

I have a progressive industries 50 amp electrical management system.
Give out amps running through the electrical system.

http://www.progressiveindustries.net...ardwired/c1p4w



2015 Columbus 320RS
2008 2500HD Duramax
2015 nights camped "34"
2016 nights camped "22"

[ilmor]

Well, regardless of who's right or wrong or who knows what, the article is a good reminder to folks not to rely on 15A to power much of anything. Personally I use it at home only to charge batteries or run the fridge. I'll also check my adapters for any signs of corrosion / dirt.

[jdavanzo]

Originally Posted by ilmor

Well, regardless of who's right or wrong or who knows what, the article is a good reminder to folks not to rely on 15A to power much of anything. Personally I use it at home only to charge batteries or run the fridge. I'll also check my adapters for any signs of corrosion / dirt.

With that I agree.

[Pathfinder75]

Originally Posted by jdavanzo

With that I agree.

X2 - Good points and cautions. Never did the AC with 15 amp but it is good to know the possible risk.

[pmsherman]

the photo in the referenced article shows a plastic case badly damaged by heat. I agree that it could potentially start a fire but, from the description of the problem, I'd be surprised if if a bad plug caused this. I suspect that the melted item is part of the on/off control for the 120VAC heater

The only part of an RV fridge that runs on 110AC is the heating element. This element should be isolated from the chassis, something I can check the next time I'm at my RV. This isolation is necessary to prevent having 110AC appear on exposed metal parts of the rig.

My Dometic installation manual shows, where circuit diagrams are provided, that the heater is connected between the hot and neutral AC power lines. It does not show that either of the lines is connected to ground. One of the lines goes through a thermostat control to switch the heater on and off as needed. If the contacts in the thermostat become pitted, heat will be created across them which should eventually cause component overheating.

I suspect that the bad plug the RV technician found was a coincidence to the overheated control board and not its cause.

Phil

[asquared]

Originally Posted by ilmor

Well, regardless of who's right or wrong or who knows what, the article is a good reminder to folks not to rely on 15A to power much of anything. Personally I use it at home only to charge batteries or run the fridge. I'll also check my adapters for any signs of corrosion / dirt.

X3. I didn't even think running AC was possible on 15Amp power so I had never tried it. This just reinforced that I never will.

[nothermark]

One thing stands out in the article:

“There are many variables that could cause the problem in this situation that are outside of the control of Dometic,” he explained. “I have never heard of this happening before.”

I think that sums up the problem. The technician was wrong as a bad connection at the cord plug should not create any problem at the board other than a low voltage condition at the heater. A loose connection on the board will heat up and do that kind of damage but has nothing to do with the cord adapter. The tech has the idea of heat due to I squared R losses but does not make the connection that the heat occurs at the point of the bad connection not somewhere else. If the circuit was open at the pin the rest of the components are expected to be designed to sit there in comfort waiting for the connection to be restored. They will not have any current so no heat.