Having trouble understanding GFCI problem

Harvard wrote:

road-runner wrote:

Harvard wrote:
Personally, I would suspect the GCFI to be faulty IF IT DID NOT trip with the 3 RVs. But then that is just me and my stray capacitance theories. :)

Just for debate's sake, if the stray capacitance were balanced, there would be equal leakage between hot-ground and neutral-ground. Exaggerated, you could leak a full amp on both sides and not trip the GFCI. As I type this, I'm agreeing with you more and more, because I've never seen the leakage to be exactly equal, with more being ground-neutral than ground-hot. So agreeing with you, I'd place my bets on the imbalance being heavier between neutral and ground.

Yes, the stray C is balanced BUT the VAC across the two is very different. The HOT wire is 120 VAC to GROUND while the NEUTRAL is almost 0.0 VAC to GROUND. Which one is going to have the most leakage current? The HOT, IMO.

I flip sides on this issue depending on how I look at it. Here's what drives the guess that the neutral-ground leakage is greater: If the leakage was perfectly balanced, the ungrounded chassis would float at half the line voltage. I've measured the float voltage of 5 or so ungrounded RVs, and in every case, the chassis float voltage has been less than half, typically around 40 volts. That tells me that the ground-neutral coupling is greater. But then there's the direct to ground leakage through jacks and tires, so it's probably not as simple as I'd like it to be.