House GFCI Tripping with MH Main Breaker Off

[Solo_RV_Guy]

Originally Posted by Busskipper

.

Not to be argumentative - BUT - if it works on a different gfi but not on the newly installed one then there just might be a a difference in quality in these new “made in China” gfi’s - so just saying - some people use logic not just what is written in the book.

And FYI the one it works on will pop with a proper ground fault - interesting that this is something that has just become an RV issue recently, sorry but it is MHO that something has changed in the last 50 years not just in the newer RV’s.

JMHO,

It's possible that GFCIs built for other locales had crept into the supply chain in the past (or maybe now, it's hard for consumers or electricians to say for sure without instrumentation to measure small currents).


It's also a certainty that some wiring device manufacturers have slippery QC tolerances (look at RV manufacturing as an example).


I think that modern RVs, whether TTs or Class As, have far more stuff that can leak current (often at seemingly tiny amounts) that, added together, will trip GFCIs. Most switch-mode power supplies (the little wall-warts and line-lumps) send their switching harmonic currents to the neutral (or ground, if separately provided by the PSU). One, two, three of these will probably have no impact until other leaking devices are connected to the service. THEN it trips.


Where there is obviously some unintended wiggle room in GFCI QC, my experience has been that more often that not, the GFCI is working as designed if it trips.


I refer back to GaryRVRoamer's post. Lots of possibilities that by themselves may not trip the GFCI, but combined, they can.

[Busskipper]

Originally Posted by Solo_RV_Guy

It's possible that GFCIs built for other locales had crept into the supply chain in the past (or maybe now, it's hard for consumers or electricians to say for sure without instrumentation to measure small currents).


It's also a certainty that some wiring device manufacturers have slippery QC tolerances (look at RV manufacturing as an example).


I think that modern RVs, whether TTs or Class As, have far more stuff that can leak current (often at seemingly tiny amounts) that, added together, will trip GFCIs. Most switch-mode power supplies (the little wall-warts and line-lumps) send their switching harmonic currents to the neutral (or ground, if separately provided by the PSU). One, two, three of these will probably have no impact until other leaking devices are connected to the service. THEN it trips.


Where there is obviously some unintended wiggle room in GFCI QC, my experience has been that more often that not, the GFCI is working as designed if it trips.


I refer back to GaryRVRoamer's post. Lots of possibilities that by themselves may not trip the GFCI, but combined, they can.

[cavie]

Originally Posted by Busskipper

.

Not to be argumentative - BUT - if it works on a different gfi but not on the newly installed one then there just might be a a difference in quality in these new “made in China” gfi’s - so just saying - some people use logic not just what is written in the book.

And FYI the one it works on will pop with a proper ground fault - interesting that this is something that has just become an RV issue recently, sorry but it is MHO that something has changed in the last 50 years not just in the newer RV’s.

JMHO,

[153stars]

We test our GFCIs at work with this tester.Some times they go weak. My MH is plugged in to a 20A GFCI I can run one A/C or its heat strip at a time . I have had the dometic fridge on 120v and Aquahot on not all at once
Greenlee 5708 GGCI And Circuit Tester https://www.amazon.com/dp/B002NQZ806..._37dWDbSXNRBP0

[powerboatr]

i got lost in all the back and forth
but


simple things first
place ALL the rv breakers in the OFF position. and turn off all appliances.



plug rv cord into gfci breaker/ outlet.
did breaker/ trip?
If yes , you have a cord problem.


if NO
then turn on the two 50 amp breakers to power up the fuse box in the coach
did gfci trip? if yes, then you may have issue between where cords attaches to rv and breaker box. GROUND maybe? if NO.


then one by one turn on each breaker and note when gfci trips. if it does not then turn on fridge and other devices and see which one causes a trip.


other gfci outles in coach trip out?


its just a basic play to check each system one by one until you find the issue.



i would add, while you have ALL the power off, 12v and a/c and inverter. that you loosen and retorque all the lugs on the breakers to ensure the wires are captured tight. they loosen pretty fast as we go down the road

[canondreams]

Thanks for all your replies!

I disconnected the power cord from the RV and plugged into the house GFCI, no problem. As soon as I reattached the cord to the RV, it tripped. I then turned off all the AC breakers on the RV panel, including the main... but it popped the house outlet again. Grrr....

So I'm assuming nothing is wrong with the cord.

Since the GFCI on my house trips even when all the AC breakers are off in the RV, then it must either be something in the 30A outlet I attach to in the RV cord compartment or something that is connected even when all the breakers are off.

Is there anything that would normally get AC even when all of the breakers are off?

[cavie]

Originally Posted by canondreams

Thanks for all your replies!

I disconnected the power cord from the RV and plugged into the house GFCI, no problem. As soon as I reattached the cord to the RV, it tripped. I then turned off all the AC breakers on the RV panel, including the main... but it popped the house outlet again. Grrr....

So I'm assuming nothing is wrong with the cord. very good assumption

Since the GFCI on my house trips even when all the AC breakers are off in the RV, then it must either be something in the 30A outlet I attach to in the RV cord compartment or something that is connected even when all the breakers are off.

Is there anything that would normally get AC even when all of the breakers are off?

Do you have a cord real? Do you have a transfer switch?

[twinboat]

Unplug the fridge, not just the breaker, and try again.

If it still trips, disconnect the white wire from the water heater element, not just the breaker, and try again.

If that's not it, disconnect the converter/ charger and try again.

Theory is, if any one of the devices has a short between the neutral wire and ground, that creates a second path for neutral current.
GFCIs monitor current between hot and neutral. A second path causes the GFCI to trip.

[Persistent]

Originally Posted by canondreams

Anyone have an idea where I should start? I was frustrated because my MH can plug into regular 30A plugs at campgrounds, operates fine with the generator, but trips the GFCI at my house when I plug it in with the adapter.

Tried two adapters... still pops. After rewiring a non-functional GFCI outlet inside the rig, I thought for sure it would have fixed the issue... still pops. I even flipped off all the AC breakers inside the MH, including the main breaker to the panel. Still pops the GFCI on my house... and the side, front and garage outlets all do the same when I try them.

I don't know what to do next! Help!!

Any 120 volt appliance with ground and neutral can be the cause even with all breakers off. As mentioned above water heaters and frig heating elements are good candidates.
Disconnect all plug in 120 volt appliances just to be sure. It is easy to do and might solve the problem.

I don't know what you are driving so can't say for sure.
A transfer switch could also be the problem. Some TS's ground the neutral when the generator is selected. This can fail and stay connected when shore power is selected.

You may be able to trouble shoot using an ohm meter. Many portable multimeters have an ohm meter.
Unplug the shore power cord and make sure inverters and generators are off.
Measure the resistance between the neutral and ground. Resistance should be very high. 20,000 ohms would allow 6 milliamps, so tripping would occur with less than 20,000 ohms.
Remove the shore power cord and check at the RV plug.
Continue moving through the circuit until you find the leak or short.

Another cause can be something still drawing power when the breakers are off.
For a GFI trip to occur some 120 device must still be drawing power. With all breakers "off", something is still drawing power and tripping the GFI. This device may or may not be the cause. Some times the 30 amp plug mounted to the side of the vehicle has a pilot light. This may do it.

The always on device may be the cause. Disconnect it to see if it solves the problem.

[153stars]

Other good leads above.I'd shut off inverter and power pull the covers to breaker box just to make sure no one bonded ground and neutral like home main breaker box as well or put neutral to ground bar. My as well tighten up all wires in there too.

[canondreams]

Thanks for all your suggestions. After ruling out the cord, I decided to follow all of the suggestions about isolating the source of the 'trip' by attaching the breaker panel wires one-by-one. I didn't even have to disconnect a single thing...

As soon as I removed the front panel of the breaker box, I immediately saw the problem. There was a wire that was attached to the neutral and ground buses!!! Removed it, and voila-- works fine. But why was it there??

Is there any reason whatsoever to do this?? Amateur work-around for something? Salesperson juvenile prank?

https://photos.app.goo.gl/a4WHqj42BMF1NPVe8

UPDATE: Just thought of this...

The GFCI next to the sink didn't work when I bought this RV. Maybe someone tried to fix it, but thought they could fix the imbalance between neutral and ground by tying them together. After trying it and failing, they just gave up and left the wire there.

[153stars]

Originally Posted by canondreams

Thanks for all your suggestions. After ruling out the cord, I decided to follow all of the suggestions about isolating the source of the 'trip' by attaching the breaker panel wires one-by-one. I didn't even have to disconnect a single thing...

As soon as I removed the front panel of the breaker box, I immediately saw the problem. There was a wire that was attached to the neutral and ground buses!!! Removed it, and voila-- works fine. But why was it there??

Is there any reason whatsoever to do this?? Amateur work-around for something? Salesperson juvenile prank?

https://photos.app.goo.gl/a4WHqj42BMF1NPVe8

UPDATE: Just thought of this...

The GFCI next to the sink didn't work when I bought this RV. Maybe someone tried to fix it, but thought they could fix the imbalance between neutral and ground by tying them together. After trying it and failing, they just gave up and left the wire there.

Glad I was able to help.
It's what you do on incoming/main breaker box in a house.Someone may have seen it was not there and bonded them by mistake " I'm not sure if one is on there from box manufacture that should of been removed", I figured they just took a shortcut with a wire/circuit to ground bar. You don't bond ground and neutral in distribution box after the main box. In like in a garage or building fed by a main panel, with one of its breakers. If you loose the neutral it will take the ground wire back. You rigs box is a distribution panel fed by a main panel breaker. Sorry i didn't think of it earlier but I'm sure you learned some things in the struggle.
I give a lot quick help/answers at work and guys will forget next time it pops up on them. You don't forget as easy and learn how a system works after a struggle ,even if you got help. Just like life I guess .

[clifford j]

Couple things have me wondering,,, The OP stated he changed where he plugged in his rv and the house gfi tripped, NOW,, he also said he had the main breaker "OFF" in his rv and the house gfi still trips, somebody tell me how his new rv gfi is causing the house gfi tripping when the main breaker has opened ALL circuits in the rv.

CLIFFORD

[clifford j]

OOOP's Just had re-thought my previous question about Main Breaker "OFF".
The main breaker does not open neutral conductor circuitry. The ground circuits and neutral circuits remain as is. Then I thought about the new GFI outlet being installed incorrectly. It's easy to reverse the line/load connections, this may be the culprit.

CLIFFORD