Hopefully I can explain this dilemma well! Here goes. I am a fairly experienced electrician, not by trade, but have been trained and have done a lot of residential electrical work. Had a cheap sinewave inverter on my 5th wheel trailer and decided it was time to make things good and safe so ordered a MultiPlus-II 2X 120V 12 VDC inverter charger. Installed as per instructions and di review some YouTube videos to learn about any "gotchas". No problems during install other than I hate push pin connectors. Screws make more sense IMHO and easier.
In inverter mode/operation when the trailer is unplugged from grid power, i have proper hot, neutral ground conditions. I.E., 120 VAC from neutral to hot, and have no fault indication on a three lamp ground wiring fault outlet tester. When plugged into grid power (shore power), I have all three lamps lit on the three lamp outlet tester and have 120 VAC between neutral and hot, 120 VAC from ground to hot and 140 vac from neutral to ground on all of trailer outlets! The ground light on the tester, (usually the far left one and usually red in color) is very dim. When on shore/grid power, the GFCI breakers will not trip when testing them with the tester. When on inverter power, the GFCI breakers will trip when testing.
The Inverter/charger is installed in a 50 Amp 5th wheel RV Trailer. All four grid power wires in the trailer, neutral, ground, L1 and L2 were pulled from the trailer's breaker panel and wired directly to the inverter/charger input and done correctly. Please Note: INPUT, GRID Power (Shore) SIDE GROUND and NEUTRAL LIFTED IN CIRCUIT BREAKER PANEL and wired directly to input of inverter. All output (inverter) wires are correctly run back to copper ground to Ground Bus, neutral to neutral bar, L1 and L2 to respective breakers. The trailer AC Grid supply is a 120 VAC 30 Amp RV plug with a 30 Amp to 50 Amp RV converter cord that internally jumpers trailer's L1 and L2 and feeds both legs, (L1 and L2) with singular 120 volt hot. The system works great! Inverter works, switches between grid power and inverter instantly when plug is pulled and boosts power when getting close to the 30 amp set point. But this is quite a voltage between neutral and ground when on shore/grid power!
Building codes and common sense state zero electricity should flow from neutral to ground, maybe a couple volts in some circumstances. I would like zero (0) volts between neutral and ground at all times and in all conditions and GFCI outlets that will trip when tested or when needed. The input and output grounds and neutrals are attached in the panel correctly and appear tight and snug in the inverter charger.
There was a similar post to this one that stated that this is just the way it is! I have to question that as it just doesn't seem safe or right.
As a test, in case I did have a ground issue, I attached the shore power ground to the ground in the trailer's circuit breaker panel and the results were the same. I thought maybe I had some kind of floating ground or non existent ground.
Any and all thoughts would be most happily recceived.
John