Hi Folks,I have a "new to me" bus conversion, built on a 1992 Flxible Metro. This is not a professional conversion but as a 30yr member of the construction industry I can tell you for the most part it is very well done and seems to follow most RV guidelines. My problem is with the fridge.. When I purchased the bus it had only a very small, AC only fridge. I remodeled the galley area and installed a used Norcold 1200LRIM, the fridge came from a trusted source and was functioning fine in Feb of this year, all recalls have been attended to. Last night, I hooked everything up and discovered an electrical problem. The fridge immediately trips the GFI, both in the coach and on the pole (it's currently plugged into just a 15 amp breaker with a 30 amp to 15 amp adapter). The trip occurs as soon as the plug hits the outlet, even before the fridge is turned on. Here is the strange part, the fridge works just fine on AC with the generator running. I have not tried to run it on propane yet but do hear that the igniter is activating. Everything else in the coach works fine, and the AC has run off this shore power plug many times with no issues so I don't think that it is a power problem. Any ideas what I should look for? Possibly a wiring issue in the shore power plug but seems unlikely since everything worked fine without the fridge plugged in. I've read several posts concerning failed heating elements but that also seems unlikely as the AC side of the fridge appears to be functioning normally under generator power. Help!?!?

I would start w/ using a polarity tester in the fridge receptical.I know, it works on the genset, but if the ground wire......ect etc........

You haven't mentioned the make / model of genset you have but it may, as many do, have a floating neutral output whereas any shore power feed would normally be N>G bonded at the distribution box, so based on this alone I'd first check both with a polarity checker to see what you have in terms of source power.

Hmm.. sounds like I need to look into polarity first, and also not rule out an internal problem due to the different type power provided by the generator. The generator is a Generac PrimePac 50 and the manual shows the "T2" lead as "a grounded neutral lead". Thanks for the replies, big trip this weekend and hoping to find the source of the issue.

2 THINGS.1. The ICEMAKER could trip a GFCI. Disconnect the leads to the Icemaker2. The Heating elements. Disconnect them. If the GFCI trip goes away, you know which part is causing it. Doug

Thanks Doug, that will be my first avenue of troubleshooting this afternoon. If the source of the trip is the heating element, and it goes away when they are unplugged, any idea why the fridge would operate normally on the genset? The ice maker is not plugged in, it has a separate 120 plug that I have not even attempted to plug in.

Help with fridge refrigerator electrical issue | Good Sam Community

dougrainer
Nomad
Jun 18, 2015
Things that I have had trip a GFCI.
1. The phone charger (Hard to believe, but it did even tho a 2 prong)
2. Power Converter
3. Miswire at the main circuit breaker panel
4. Burnt/melted wires at the Main Breaker panel
5. miswire of receptacles downstream of the GFCI
6. miswire of the GFCI
7. Bad/charred relay at the 50 amp transfer box
8. Appliances (non RV) plugged into GFCI controlled receptacles
I turn off all the breakers and if the pole GFCI does not trip, I then turn on each breaker until I find the circuit that trips the GFCI. Then you have to trace that branch circuit down, disconnecting/inspecting items until you find the source. Doug
westend
Explorer
Jun 18, 2015
todintexas wrote:
You are talking about the shore power cord, correct? The cord itself is in excellent condition, nothing loose at the plug. However, there is a splice between the shore power cord and the distribution box. I'll take that apart this evening and make sure there are no obvious problems.
I don't know what you have for cords or how you are connecting the fridge. The scenario you describe (runs on genset--trips GFCI on shore power) may indicate a neutral-ground problem. Yes, if you have a splice, that would be one of the first things to check. You can check the integrity of your cord sets to make sure there is continuity where there should be and no shorts/opens.
todintexas
Explorer
Jun 18, 2015
You are talking about the shore power cord, correct? The cord itself is in excellent condition, nothing loose at the plug. However, there is a splice between the shore power cord and the distribution box. I'll take that apart this evening and make sure there are no obvious problems.
westend
Explorer
Jun 18, 2015
Bad cordset. The generator doesn't care about neutral-ground bonding but your GFCI's do. Inspect the male plug and see if the ground prong is loose.
todintexas
Explorer
Jun 18, 2015
Just thought I would throw out and update if for no other reason than curiosity, LOL. Today the fridge is a good news/bad news scenario. Yesterday, the fridge continued to kick the GFCI when plugged into the pole, even with the heating elements disconnected. But when I plugged it into my portable generator, not the on-board genset, it ran fine for about an hour. At the end of the hour I shut down the portable generator and plugged the coach back into the pole, this time it did not kick the GFCI. Here is the good news, fridge ran fine all night plugged into the pole and was very cold this morning. Bad news, I have no idea what was causing the problem and we all know when it decides to happen again it will be at the most inopportune time! Thanks for all your help. going to try running it on propane tomorrow.
todintexas
Explorer
Jun 16, 2015
Thanks again Doug, my 1200 has the separate plug for the ice maker. The refer is off when it trips, that is what is the most confusing at this point. As soon as the plug hits the socket, click... of it goes. Thinking out loud, the GFCI in the coach was tripped once, I wonder if it may be coincidental and the fridge plug I am using is not even on that GFCI circuit. Could be a problem in that plug itself although the little fridge was working in that position. I'm going to locate the heating elements when I get home and unplug them, see what happens.
todintexas
Explorer
Jun 16, 2015
very interesting... if nothing else I have learned a lot today. I'm pretty confident in the generator wiring, I just installed it and followed all directions and recommendations to the letter. I think I'll disconnect the shore power line just to make sure all is well and check all connections. But, as you say, it's something related to the fridge or the fridge plug as the GFCI on the pole does not trip with anything else in the coach.
DrewE
Explorer II
Jun 16, 2015
todintexas wrote:
Interesting, thank you, I'll need to look into it further this evening. When plugged into shore power, the moment you plug the fridge in it kicks the GFCI at the pole. On one occasion, it kicked the GFCI both in the coach and at the pole simultaneously. It was running correctly on the genset, but only for a short time. I'll check polarity, leave it run for a while on the genset, then pursue the troubleshooting avenue suggested. I see where the 30 amp shore power plug has been replaced,just the plug and not the cord, I assume that any bleed through inside that repair could cause this also?

It is not at all likely that the plug could cause what you're seeing, as the ground fault would exist whether or not the fridge is in use. I'd say it's impossible, but I've learned to avoid using that word when analyzing problems...but practically speaking, it's not possible to match what you're seeing.

A GFCI compares the current flowing through the hot wire with the current returning through the neutral wire. If they are not exactly balanced, it trips, as the excess current is flowing through some other path. If there were a fault in the replacement plug, any electrical use in the RV at all would cause the GFCI to trip--and sometimes that would not even be required, depending on the GFCI and the exact nature of the fault. The camper GFCI would not trip, however, as from its point of view the currents would be balanced.
dougrainer
Nomad
Jun 16, 2015
todintexas wrote:
Thanks Doug, that will be my first avenue of troubleshooting this afternoon. If the source of the trip is the heating element, and it goes away when they are unplugged, any idea why the fridge would operate normally on the genset? The ice maker is not plugged in, it has a separate 120 plug that I have not even attempted to plug in.

There are 2 models of the 1200. 1 model has the separate Icemaker plug and the other the 120 is spliced into the 120 wiring of the refer. IF the refer is OFF, then the 120 Heat Elements are not activated. So, if they were bad, they should not trip the GFCI if the refer is OFF. But, that is why I suggested unplugging the Heat elements from the control board. Take them out of the loop. Doug
todintexas
Explorer
Jun 16, 2015
Interesting, thank you, I'll need to look into it further this evening. When plugged into shore power, the moment you plug the fridge in it kicks the GFCI at the pole. On one occasion, it kicked the GFCI both in the coach and at the pole simultaneously. It was running correctly on the genset, but only for a short time. I'll check polarity, leave it run for a while on the genset, then pursue the troubleshooting avenue suggested. I see where the 30 amp shore power plug has been replaced,just the plug and not the cord, I assume that any bleed through inside that repair could cause this also?

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