GFIC G-N fault at converter

[FRGrimes]

Hi Guys / Gals - new to the forum and new to travel trailers. Wife and I just got a 2001 travelstar 21CK hybrid on Sunday. We quickly found that once we removed the "cheater plug" we were tripping the GF. After much reading on this and other forums, I've tracked the problem down to a G-N fault at the converter (if I disconnect the neutral that goes into the converter, the GFI no longer trips).

My question is: Any ideas on what's next? Can I isolate the problem to to the converter, or can the problem be residing in the 12V circuits coming out of the converter?

Thanks!

[daleross]

Sorry Jframpey, didn't read your post. Yours should be dead on.

[daleross]

In your electrical system (120volt side) The grounding conductor and the neutral conductor (white wire) should not be joined together or touching. Had a similar problem, plugged into campground power and it would trip the 30 amp GF breaker. Found some faulty wiring at an outlet, the bare ground was routed close to a white wire which had improper stripping and the two were barely touching. Yes, its a witch hunt but that is where I would start. Use a volt-ohm meter to tell if they are joined somewhere. Go to your RV plug and test the ground and the white. If the needle swings (analog) it is shorted together. Good Luck.

[Jframpey]

As said above a GFCI compares current between the hot and neutral... In this case at the receptacle in the garage. The OP said with a "cheater" adapter in place (ground lug cut off) the GFCI doesn't trip, so, the leakage is from the neutral to ground. Removing the neutral from the converter at the RV panel also prevents the GFCI from tripping.
(After further thought it could be a hot to ground fault... But that would normally trip any breaker)
1). Observe the neutral bus bar in the RV panel. All of the neutrals should connect to one bus bar (white wires) observe the ground bus bar(the bare conductors) these should be on a separate bus bar. If there are any crossed wires (whites and bare conductors) this will trip the GFCI.

2). Turn off the breaker supplying the converter... If the GFCI still trips with other loads running the fault is N-G in the wire or converter.

Try these tests and let us know the results and we can isolate the culprit.

Joe

[Jframpey]

I think the OP means that he is tripping a GFCI in the garage when he hooks up the RV...

[westhedgeapple]

Do you mean that your power converter uses an ungrounded adaptor? If you can carefully inspect your converter see if it has the words "Made in China" on it, if so mark all the wires , remove it and use a 20 lb. hammer to reduce it to something that can never be hooked up to electricity again. Next go out and buy a comparable size USA made converter by http://www.progressivedyn.com/rv_converter
or a couple other makers and install it in its place, this should cure the problem and prevent burned up batteries and smoking converters. When you isolate the ground you defeat the GFCI. My other question is why the converter would be on a GFCI in the first place, most are direct wired to an individual breaker, The 12volt DC cannot utilize ground fault circuits, they are AC only. The only RV receptacles that must be on a GFCI are the bathroom, kitchen and outside ones. Most RV makers daisy chain these to one GFCI receptacle in bathroom. Also if the GFCI has been subjected to a nearby lightning strike or severe voltage surges it is probably bad and needs to be replaced. Also the 2009 Electrical code lowered the trip point on GFCIs from 6Ma. to 4Ma. so newer ones trip in uses that older ones did not.

[westend]

Hot skin effect

From one of his articles and pertinent here: "An RV Hot-Skin condition occurs when the frame of the vehicle is no longer at the same voltage potential as the earth around it. This is usually due to an improper power plug connection at a campsite or garage AC outlet."

[beemerphile1]

You have a potentially very dangerous situation.

Use your favorite search engine to look up "No shock zone" by a chap named Sokol. He has lots of good articles about the electrical risks with RVs.

[Gene_Ginny]

I agree with ScottG. Let me amplify a bit. In simple terms, a GFI measures the current flow in the hot wire and the neutral wire. If the current in each wire is not exactly the same the GFI will open the circuit. Why would the current be different in the hot wire and the neutral wire? Because some current is flowing from the hot wire to the ground wire. As long as the ground wire is connectec to an earth ground there is no safety problem BUT many times a second problem happens, the ground wire becomes disconnected. When that happens the so called ground becomes a live wire. Anyone touching the live wire and a real ground may get a deadly shock.

[ScottG]

Your RV guy is wrong, a ground fault is a real safety issue - he probably just doesn't understand what it means.

[westend]

The DC side should have nothing to do with GFCI compatibility. A bad battery or short in the DC side may cause a draw that exceeds the converter's capability and that may cause the converter to fail or a circuit breaker to trip, either a DC breaker or AC.
An easy check to see if the converter is functioning is to measure voltage across the battery terminals when the converter is powered. A voltage of at least 13.5 should be present.
I'm with Scott G's diagnosis--Not knowing the exact history of the converter, the most likely situation for a GFCI trip is that the hot and neutral are reversed.

[FRGrimes]

OMG - tracking it down to a staple!

I just talked to a trailer electrical repair guy and he felt like it was no big deal - that some converters simply don't play nicely with GFI's. Not sure that I'm fully comfortable with that answer. It seems (from what I've read on these forums), opinion is split on this issue, with half agreeing with the repair guys' opinion, and half saying whenever your tripping a GFI its a safety issue that should be tracked down and corrected.

Everything works (AC, microwave, battery charging, etc) if I use a cheater plug (without a ground), and I suspect that everything will work fine on a non-GFI outlet. It sounds like many areas are going to GFI only, and the cheater plug seems like a bad idea in general.

Other than disconnecting the converter from the battery, are there other ways to make sure the problem is within the converter itself. Can problems on the DC circuits cause this problem? (such as a staple hitting a DC line, bad water heater, etc)?

[beemerphile1]

When I brought my trailer home it also tripped the GFCI. I found the problem to be a staple in a run of Romex to the A/C unit. It wasn't shorting the hot wire, it was bridging the neutral and ground.

Ground faults can be difficult to find but it sounds like you are on the correct path.

[ScottG]

It sounds like the power connection to the converter is reversed. Its neutral wire is probably connected to the breaker. Or if it has a plug, it or the receptacle is backwards.
If that's not it the the converter is shot.

[newman_fulltime]

it goes to the batt and panal at the same time on most yes unwire or pop the breaker if you do this it takes the converter out of the loop.the batt charger is now acting as your converter