norcold refer trips shore power gfi circuit

[tjpolsin]

I am now all know'd up on why my shore power kept tripping the GFI circuit whenever I started my refrigerator on 120V AC.

I can now pass all this knowledge onto you-all faithful RV'ers.

A GFI circuit will trip due to a small short to ground, like excessive steam in a bathroom getting into a circuit.

For my NORCOLD N611RT, the 120V AC heating element started to exhibit deteriorating internal insulation. After much sleuthing on the Google machine, I found this to be a common culprit to this symptom. The resistance to ground of that heater should be close to 2000K ohms. In my case, I measured about 150K ohms, which was enough to trip my shore-power GFI. This indicated that the heating element insulation was breaking down (not surprising as the trailer is 9 years old)

I ordered a new element, and with the help of youtube, was able to replace the element without removing the refer.

My one piece of advice is to take a picture of the circuit board BEFORE you start taking leads off of it. I would have saved an hour of google time had I done that first.

Refer is back up and running on shore power.

Tim
2008 Jayco 26BHS.

[Vicr]

The imbalance in the load need only be 5 milliamps to trip the GFCI. Not much considering it takes about an amp to light a light bulb.

[norty1]

Good info. Most of the time the GFCI will also deteriorate and give a false reading causing it to trip.

That would be a bear to find.

[tjpolsin]

Originally Posted by norty1

Good info. Most of the time the GFCI will also deteriorate and give a false reading causing it to trip.

That would be a bear to find.

At the house, the trailer is plugged into a 20amp GFCI protected ckt.
The issue was intermittent last year and I though it was related to having my batteries disconnected. And the GFCI only tripped when I started the frig. I ran the AC, used the trailer outlets to power an aircompressor, vacuum, and carpet cleaner with no problems.

During our trip last year to Yellowstone last year, the trailer was always plugged into either non-GFCI protected 15amp ckt or 30amp RV pedestal. so the ground went undetected.

The GFCI tripped again this year when I turned the frig on in prep for our camping trip this past weekend. The web is full of similar stories and some helpful troubleshooting. Checking the heating element's insulation resistance was a fairly non-intrusive test. The reading for my heater was between 100 and 400Kohms. After conferring with an electrical engineer neighbor, we both concluded that the heater's insulation had broken down and the element needed to be replaced. (the reading should be 1500Kohms or greater)

The element is a bit of a bear to get out, but can be done without removing the frig from the trailer. Once I replaced the element and (correctly) hooked it back up, the frig worked like new.

Did I mention to take pictures of the circuit board connections BEFORE you take the wires off?

Tim