Norcold tripping ground fault on shore power

[rjdelapp]

I have a 98 norcold model 6162 that tripps ground fault in my garage when turned on ac power. The duplex is wired correctly in garage and test correct where fridge plugs in on rv. It works fine on generator power. I leave fridge unplugged and ground fault never tripps. RV is a 98 Damon Daybreak. Any ideas??

[ottffss]

I'll guess the Norcold electric heater element has an internal electrical leakage which causes the garage GFCI to sense a current on the ground thus triggering the GFCI. Maybe clean/tighten all the elec heater connections on the Norcold but it might be you'll need to replace the heater element. Take the heater element out of the circuit and see if GFCI still trips. Another thought is to get a portable GFCI outlet (big box hardware store) and run the Norcold through it while on genset power to see if it trips that GFCI. It's possible the garage GFCI is just a little over sensitive. GFCI's (and heater elements) can age.

[rjdelapp]

I checked the ohm's of the electric element (52 ohm) and to ground - did not get any readings to ground. It does not trip if the element is disconnected. Could it be that a heating element is just a big shorted coil to produce heat and the gfi thinks it's a short to ground?? Confused!!

[ottffss]

Checking static ohms for a current path and having an electrical leakage *under load* can yield two different results. Also, your ohmeter may not be sensitive enough to detect the resistance path that the GFCI detects as an imbalance of around 10milliamps between the ground and neutral.

Obviously from your detective work it is the heater element leaking to ground under load. It is possible that the wires on your element may be installed reversed. But, it looks like you'll need to replace the element to solve the problem (unless your garage GFCI has aged and is oversensitive).

BTW yes, a heating element is essentially a "big shorted coil" (of apparently 52ohms in your case) the problem may be the shielding of the element wire might be breaking down with age/moisture thus allowing current to leak - causing the neutral-gnd imbalance the GFCI is detecting.

[mfire1339]

"It works on generator power" is interesting. Do you mean bypassing the duplex box?


Mike

[ottffss]

Quote:

Originally Posted by mfire1339 "It works on generator power" is interesting....

It's a GFCI tripping issue. No GFCI in the circuit when on genset power. The refer trips the GFCI when shore is plugged into the garage GFCI outlet. If I understand it correctly....

[RV Wizard]

How qickly does the GFCI trip? If it takes a couple seconds the filament of the heating element may be expanding inside the case and touching it to cause the leakage and tripping GFCI.

[Steve N Sal]

There's an inbalance in the neutral going on somewhere. Must be something internal going on with the refrig.

[rjdelapp]

Quote:

Originally Posted by mfire1339 "It works on generator power" is interesting. Do you mean bypassing the duplex box? Mike

Normal generator operation with refer plugged in duplex, no shore power.
I did unhook the ground wire from the 120v cord to fridge and still trips gfci instantly. Fridg may be grounded to chassis frame somewhere. Will replace gfci later today.

[rjdelapp]

Found problem in the garage GFCI - 2 loose wires, ground and hot. Not the first time with house wiring problems. Thanks for all the help.

[KIX]

Quote:

Originally Posted by rjdelapp I checked the ohm's of the electric element (52 ohm) and to ground - did not get any readings to ground.

We no longer have a Norcold but if I remember correctly from when we did have one and had problems.........the heater elements when new should read 64 ohms. Ours was a 1200 series and I think you have a different model but, again, I thin k the heater specs are the same. If yours read 52 ohms it sounds like yours is/are going "South".