Neutral to Ground bond question

[Hein]

Originally Posted by Al and Missy

You asked

Current on the ground wire has nothing to do with GFCI actuation. A GFCI senses the local current on the hot (black) wire and compares it to the neutral (white). If it exceeds a certain value (I don't remember the number so I'm not going to guess) it trips. That is how they are specified and tested for acceptance.

Al

Thank you for clarifying. If there is current on the ground then would that not reduce the current on the neutral and cause an imbalance that then causes the GFCI to trip?


All the best,
Hein

[uncle_bob]

Originally Posted by Ephraim

That may be an option. Right now, the drawer under the read dinette seat is unusable space. The wife wanted to protect the woven flooring so she got natural fiber rugs to cover pretty much everything. Then she got worried that natural fiber next to the stove wouldn't be a good thing so she covered that with a padded rubber mat (cause she liked the feel of standing on that). Yep, you read that right. We have a rug to protect the rug to protect the rug that protects the floor. What is a guy going to do...

Anyway, that means you can't open that drawer without moving rugs. I might just confiscate that space for batteries.

Hi

I realize this is *way* off topic but ok .....

Scattering batteries all over the trailer is generally not a great idea. You have this giant cable that goes to the inverter .... where does it go? You *could* put in a 4/0 cable to each set of batteries. Even then, the batteries with the shortest cable will "win" and supply more of the load. That's not ideal for battery life. Just how non-ideal depends on the length of the cables and how heavy your usage is.

So - simple answer, if you confiscate the area under the seat, also move the giant pile of cables under there and see if you can fit 6 batteries all in the same place.

Bob

[wizardglass]

Pick yourself up an outlet tester, under $10 on Amazon (ok, that's still spending money...) Very small item to keep on hand. You can test the outlet where your plugging into, and also in your camper in a few seconds. I use it before plugging in at campgrounds.
Also consider replacing your GFI in the camper. They do go bad and can start tripping under a "normal" load surge.
I also keep a 15 amp meter that plugs into an outlet, it will show your line voltage and power draw from anything plugged into that unit.
A multimeter can help you trouble shoot beyond that, but the above items are quick and easy for your camper tool box, even if you've isolated your current issue with your inverter, they're good items to have on hand.

[rickst29]

Originally Posted by Hein

Thank you for clarifying. If there is current on the ground then would that not reduce the current on the neutral and cause an imbalance that then causes the GFCI to trip?

Yep.

If your inverter remains powered up, or it's disconnection method affects only the "hot" 120V interconnect, then your Inverter allows the 120V shore-powered appliances to "leak" current into the 12V negative bus.

In Airstream, the 12V system is negative grounded: The frame, the battery terminals, and many "white wires" are all interconnected. But, when the 120V power cord is connected to shore power, this bus (i.e., the frame and aluminum skin) are connected to the power cord GREEN safety wire.

At the Inverter, even if the 12V "hot lead" (and/or 120V "hot" output leads) are disconnected, the safety "green" and current carrying neutral "white" leads for 120V service are apparently still interconnected with that 12V grounding bus. (The potential of the 120V "grounded" connection floats a bit, via high capacitance - but it's not going to differ by much.)
- - - -
Your problem is: An 120V appliance, powered by shore power through a GFCI, can leak return current back through the GREEN wire on the Airstream power cord. The return current path is: appliance cord -> socket -> white wire -> Current carrying Neutral Bus. At this point, some current goes out (correctly) through the white wire of the poser cord. But at least some current also goes through white wire(s) into the Inverter.

The Inverter behaves as a power panel without an explicit grounding lug. The current-carrying "white" return current leaks to the frame ground, and it then gets routed out through the power Cord GREEN safety wire.

The GFCI at the facility sees unmatched current (returning "neutral current too small), and trips up. You need to disconnect both the 120V Inverter "hot" and Inverter "current carrying neutral return" leads (or busses) from the 120V system when shore power is present.

[clarkter]

Same problem. We finally had to install a 30 amp. Dealer tried to help. Called airstream and they wouldn’t acknowledge it was a problem. We should all drive to airstream and protest.

[cesaro]

I have a 2014 INTL AS. When I connected a 30amp power cord with a 15 amp male plug at the RV Storage area, the GFCI tripped instantly. I never had this problem when connected at the RV Parks using 50 amp power. What can I do to use the 120 Volt outlet?

[Ephraim]

Originally Posted by cesaro

I have a 2014 INTL AS. When I connected a 30amp power cord with a 15 amp male plug at the RV Storage area, the GFCI tripped instantly. I never had this problem when connected at the RV Parks using 50 amp power. What can I do to use the 120 Volt outlet?

Try turning the breaker off in your trailer that the Inverter is tied to. That works for me unless I need the outlets that the inverter controls (Entertainment & couch systems).

Outside of that, you'll have to replace the stock WFCO inverter with something else that doesn't have this issue. As far as I can see, the problem isn't really Airstream other than the fact that they chose an inverter that doesn't like to be connected via a GFCI outlet. I know the Victron will work. I'm sure there are others too.