Ogrape1

8 hours ago, oldjohnt said:

Ogrape and RV, good morning, FWIW here are one electrical power engineer and lawyers thoughts:

1) For whatever reasons, lawyers fearing liability or engineers representing an RV park may have insisted upon some sort of GFCI protection (regardless if code requires or not) be it at individual receptacles or GFCI breakers and as the effects are cumulative and it takes ONLY 0.005 amps to trip ONE OR MORE RV'S PLUGGED INTO GFCI PROTERCTION CIRCUITRY CAN EASILY CAUSE A TRIP.

2) As I mentioned before the slightest excess moisture or humidity, dirt or dust, insects, all the sorted appliances, RVs with external receptacles, and the fact ground faults can be cumulative (one or more RV's) MAKES IT SO EASY FOR RV(s) TO TRIP A GFCI 

3) There could be some issues (Inverters or Generators) with the NECESSITY THERE BE ONLY ONE NEUTRAL GROUND BOND. When an Inverter or Genset is configured as a Separately Derived Source with a BONDED Neutral and the RV frame serving as the Grounding Electrode, depending on how the transfer arrangement is configured (How many poles, Neutrals switched or not???)  THOSE DEVICES CAN CAUSE A GFCI TRIP if there are multiple Neutral/Ground bonds. In order to avoid having more than one NG Bond (AS I understand but NO warranty) some transfer switches bond the gensets Neutral when its in use but open it otherwise and similar some Inverters use some sort of a bonding relay ONLY when the Inverter is operating THOSE ARE TO PREVENT MULTIPLE NG BONDS which could cause GFCI problems. Not long ago when on Inverter power a GFCI tripped instantly when my microwave started but when I plugged it into a different outlet (still on GFCI but different location) it worked TALK ABOUT A MYSTERY the problem appeared to be a CIRCUIT (still worked otherwise) instead of the microwave. 

DISCLAIMER These issues are complex and deep in the weeds difficult to trace and diagnose even if there let alone over the net grrrrrrrrrrrrrrrrrrr

4) DIAGNOSE  One method I've used is to one at a time remove/unplug/disconnect/flip breakers feeding loads, appliances or circuits to locate the problem, WHICH MAY BE AN APPLIANCE ITSELF OR THE CIRCUIT/OUTLET STRIP feeding it.  

BOTTOM LINE I just cant from here diagnose YOUR problem, but the FIRST suspects are the RV,,,,,,,,Or the parks service is GFCI protected perhaps with a breaker,,,,,,,,,,Or an Inverter/Generator bonding issue,,,,,,,,,Or multiple NG Bonds,,,,,,,,,,, Or some sensitive electronic devices FOR REASONS I CANT EXPLAIN ESPECIALLY ON START UP  cause a GFCI to trip.

 Sorry no answers just theory and suspicion, but I try my best.

John T   BSEE,JD

oldjohnt and others, I have some good news based on your lengthy but excellent posts.  I unplugged the 14x3 AWG cord from the inverter and... no GFCI tripping when plugging in to 20A shore power.  I'll have to dig deeper but I'm suspecting I have multiple NG bonds.  Having said that, I am tired of digging and kind of like having a solution that is so simple.  We almost always boondock: I can put a "Note to Self" on the shore cord to unplug the inverter before shoring up.

The quasi mystery still for me is why this suddenly happened after months and months and months of connecting the same 30A shore power line with adapter to the same 20A GFCI outlets in my garage.  I do not know of one change in any of the RV's equipment or devices, and no changes in the house/garage either.

I can't see how turning on the inverter prior to connecting to the 20A GFCI shore power, as some have suggested here and on other sites, will work with the way my inverter is wired (rough schematic attached).  The inverter sends power to everything that is 110v. in the coach.

Thanks to all who have pitched in here.  I appreciate it.

Well I've got a strange one.  When I plug my 2019 Orion T24RB motorhome in to shore power (110 volt, 20 amp) the shore outlet's GFCI (at home) or breaker (at campgrounds) immediately trips.  I've tried over three different 20 amp GFCI circuits and the same thing happens.  I've tried three different 30 amp to 20 amp adapters and the same thing happens.  I've tried two different 30 amp power cords with adapters and the same thing happens.  Same if the rig's main panel breaker is switched off.  You're noticing a pattern here.
When I plug directly into any 30 amp shore power outlet, everything powers up.  When I fire up the gen set, everything powers up.  When I turn on the 2000 watt inverter you guessed it, everything powers up.  Another pattern.
I've traced and disconnected all the electrical lines from their source into and out of the automatic transfer switch.  Into/disconnected = no 20 amp GFCI tripping.  Out/disconnected = shore 20 amp GFCI trips.  Recall there is no GFCI/breaker tripping with 30 amp shore power, only 20 amp.
What the devil is going on here?  Everything has been working perfectly for over a year until this started about three weeks ago, and nothing has changed.  BTW the inverter wiring circuit has its own DPDT relay switch.  I even replaced that (with a spare I conveniently had) but it made no difference.
I'm stumped and would appreciate your wise counsel before I hand my wallet over to my local RV service dept.  Thanks,   Gary