Shore Power GFCI Tripping

[AirstreamJim]

No luck. In fact, the situation is worse than it was.

Here's my current situation: All wires in the AC distribution panel are properly connected (hot, neutral, ground). All breakers (including Main) switched OFF. Plug shore power into a GFCI-protected outlet in the house, and the GFCI trips instantaneously. I'm thinking there's something bad happening before the power even gets to the distribution panel.

I disconnected hot, neutral and ground from the incoming line from the shore power inlet. Plug it in, and the GFCI holds.

I reconnected the ground wire to the ground bus, and the GFCI still holds.

I reconnected the hot to the (Main) breaker and the GFCI still holds.

I reconnected the neutral to the neutral bus and the GFCI trips.

I disconnected the ground and the GFCI holds.

Just to be sure, I disconnected the hot from the Main breaker, left neutral and ground connected to their respective busses, and the GFCI trips.

So bottom line is if both the neutral and ground are connected to their respective busses, the GFCI trips. Disconnect either one, and the GFCI holds.

I believe now that the fault is in the main wiring between the shore power inlet outside and the distribution panel. Does this sound right? Are there other possible causes for what I'm seeing?

I tried to take off the shore power plug on the outside of the trailer to see if there's anything going on with the wiring. I got the 4 screws off but the plug would not come out of the trailer. There has to be a way to get it off because people replace it with a premium Furrion plug and cover. I couldn't figure it out, though. Any suggestions are welcome.

Unless someone has better ideas, I'm afraid I've done as much as I can. What scares me is if the main cable has to be replaced. That has to be a huge job with interior panels removed. That's a job I cannot afford.

One last thing: I have not considered the DC side of the distribution panel at all. Should I be doing something there?

I'm all ears, guys.

Jim

[GMFL]

You Sir have a neutral to ground short. Either the house GFCI is bad or the power cable or the shore power plug or could be the 30amp to 15amp dongle.

[Al and Missy]

Reference your statement that the GFCI trips with ground and neutral connected and hot disconnected, the house GFCI should not be tripping if there is no connection to the hot wire. I suspect a problem with the wiring of the shore power connector on the trailer. This sounds like a hot-neutral reversal in the wiring, but I'm having trouble figuring what could have happened such that it has worked all this time and suddenly failed. Was there a storm recently that could have brought a lightning surge into the trailer? Maybe an arc left a carbon track on the connector. I think you are going to have to figure out how to get access to the back side of that connector.

Al

[AirstreamJim]

Originally Posted by GMFL

You Sir have a neutral to ground short. Either the house GFCI is bad or the power cable or the shore power plug or could be the 30amp to 15amp dongle.

I agree. I have eliminated the house GFCI as the source (I've used two different GFCI outlets). I also have eliminated the power cables and dongles as the source (two different power cables and dongles). That leaves the shore power inlet on the side of the trailer, or the interior wiring.

Originally Posted by Al and Missy

I suspect a problem with the wiring of the shore power connector on the trailer. This sounds like a hot-neutral reversal in the wiring, but I'm having trouble figuring what could have happened such that it has worked all this time and suddenly failed. Was there a storm recently that could have brought a lightning surge into the trailer? Maybe an arc left a carbon track on the connector. I think you are going to have to figure out how to get access to the back side of that connector.

I think you're on to something with the carbon track thought. The ground connector on my shore power cable recently showed signs of heat and charring at the trailer end (I noticed it at the end of our Memorial Day weekend trip); there is slight char on the trailer connector's ground lug as well.

I just need to figure out how to get the connector off the trailer to troubleshoot and replace it.

Jim

[uncle_bob]

Hi

This is to the point that you probably should get an electrician to look at it.

The fact that the ground wire was sitting loose in the box suggests that there may have been a basic issue with the wiring all along. I don't see how that wire just magically decided to sit there by it's self. If it is a long term screw up, verify everything. If you can't get the plug off, use an multi meter and some long leads. Check where each shore power wire goes and check them for shorts.

If the trailer was un-grounded (relative to shore power) you may have taken damage in a storm. Even with the shore power wired right, you can still take damage. That's why people buy surge protectors. It's also why some of us buy expensive surge protectors. Where and how to protect against what is part of a whole different (and very long) debate.

If you have damage, it may or may not show up with a simple multimeter check. There are fancy pieces of gear that check at higher voltages that will show issues that a multimeter will not. Unless you are an equipment freak (guilty !!) you probably don't have one of those in your tool kit. Your local electrician may or may not have one in his truck either. He should know where to grab one.

Bob

[AirstreamJim]

Originally Posted by uncle_bob

If it is a long term screw up, verify everything. If you can't get the plug off, use an multi meter and some long leads. Check where each shore power wire goes and check them for shorts.

I've rechecked every wire in the AC distribution panel, made sure only neutrals to the neutral bus, grounds to the ground bus, and hots to individual breakers. There are some anomalies in the distribution panel wiring (those pigtails - clearly there intentionally but not doing what they're supposed to do and could (should) be taken out of the equation), but nothing that is wired wrong. All connections are tight and no wiring appears to be defective or damaged. But I can't get that damned 30 amp inlet off to replace it.

If the trailer was un-grounded (relative to shore power) you may have taken damage in a storm. Even with the shore power wired right, you can still take damage. That's why people buy surge protectors. It's also why some of us buy expensive surge protectors. Where and how to protect against what is part of a whole different (and very long) debate.

We use a Progressive EMS-PT30C surge protector. No faults reported since we began using it last year.

I've asked Airstream Service for hints on how to get that 30 amp inlet off the side of the trailer. Hopefully they can help me out. Until then, no AC power for us, we'll be depending on our solar charger for battery charging.

Jim

[David F]

I'm guessing your inlet socket is at fault. Could it be sealant that is holding it in place and you just need to pry it free? Looking forward to hearing the final resolution.

[RinconVTR]

Turn off all 120v circuit breakers except what powers the GFCI outlet. Narrow it down to the single circuit that trips the GFCI and focus on devices on that circuit and their wiring.

[davidz71]

I had a short in my 30 amp shore plug one time that kept tripping the campground pedestal. A factory maintenance worker ran a jumper between the neutral and ground bus without telling me because he said that is what they do in the factory he worked in. THIS does not work on a GFCI circuit! It will trip the circuit every time.

Set me straight, did you say that you had been running your air conditioner off a 15 amp circuit in the house? That is a good way to burn your air conditioner up! You must run the air conditioner off a 30 amp circuit. It could also be that there is now a problem with the air conditioner breaker or as mentioned earlier a problem with the GFCI receptacle because it has tripped or overheated too many times.

Lewster may have more input into this situation.

[The Colonel]

Hey Jim, you got a real mystery there. I don't think you mentioned this but, with convertor CB open and AC in off did gfi still open when you closed AC breaker?

[David F]

[QUOTE=davidz71;1960930]

Set me straight, did you say that you had been running your air conditioner off a 15 amp circuit in the house? That is a good way to burn your air conditioner up! You must run the air conditioner off a 30 amp circuit. QUOTE]

The above statement confuses me. So long as you don't overload the circuit with the a/c load, then it does not matter what amperage the circuit is rated for. The a/c wants voltage to be within a (small) range, it will pull the amperage it needs and if the circuit cannot handle it, it will trip the breaker.

[uncle_bob]

[QUOTE=David F;1961009]

Originally Posted by davidz71

Set me straight, did you say that you had been running your air conditioner off a 15 amp circuit in the house? That is a good way to burn your air conditioner up! You must run the air conditioner off a 30 amp circuit. QUOTE]

The above statement confuses me. So long as you don't overload the circuit with the a/c load, then it does not matter what amperage the circuit is rated for. The a/c wants voltage to be within a (small) range, it will pull the amperage it needs and if the circuit cannot handle it, it will trip the breaker.

Hi

The gotcha is the starting winding on the compressor motor. It pulls a lot of current for a brief period. It is not long enough to trip a breaker (by design). If you have a really nasty feed (like a 250' long #14 extension cord), the voltage drops when the motor start winding cuts in. That keeps it on the start for much longer than normal. It should not come as a surprise that they make the start winding as light as they can (cost !!). If it sits in startup too long and repeats the process many times, you either loose the winding or some other part of the start circuit. Yet another reason to get one of the soft start kits ....

Bob

[AirstreamJim]

OK, catching up here.

Originally Posted by RinconVTR

Turn off all 120v circuit breakers except what powers the GFCI outlet. Narrow it down to the single circuit that trips the GFCI and focus on devices on that circuit and their wiring.

Thanks, but we're way past that step - did all that 3 days ago.

Originally Posted by davidz71

Set me straight, did you say that you had been running your air conditioner off a 15 amp circuit in the house?

No, I said I have not run the A/C when plugged into the 15 amp house outlet. I plug in to the house only to keep the batteries charged.

Originally Posted by The Colonel

Hey Jim, you got a real mystery there. I don't think you mentioned this but, with convertor CB open and AC in off did gfi still open when you closed AC breaker?

The GFCI trips with every single circuit breaker, including the Main, open (turned OFF). It does not need any breakers closed to trip the GFCI. I never get the chance to close any breakers because I cannot power up the system when plugged in to the GFCI outlet.

OK, so here's where I am now: Airstream told me to "gently force" the 30 amp inlet out of its home on the side of the trailer, so with a little more "gentle force" I managed to get it out far enough to unscrew the wires and remove the inlet. I then hard-wired a line from the house to the shore power feed wires hanging out of the Airstream. Still trips the GFCI. So now I know the inlet connector is not the problem, it's probably in the wiring between the inlet and the AC breaker box.

I've made an appointment at the mother ship for late August in case it turns out that the wiring between the inlet and the breaker box is defective. Opening up walls or the belly pan (I don't even know how that cable gets up there - I assume through the belly pan) is way beyond my skill level.

In the meantime, I will try to find someone with good electrical test equipment and troubleshooting skills to verify what I've deduced so far and see if we can find something that I've missed with my limited skill set. If anyone has any suggestions, I'm all ears. Otherwise, I'll leave it to Airstream to fix.

Thanks to all so far - you've all been a great help. This is why I love the Airstream community!

Jim

[uncle_bob]

Hi

I'll bet a bottle of beer on them finding a very tight cable from the inlet to the breaker box. It simply took a long time to chew through the insulation.

There are various things you can try to isolate what is what. They aren't going to do you much good. You have pretty much proven that the cable is toast. Any improvisation you do from here on would be risky. About the only safe thing would be a power cord that goes straight into the breakers and runs out the main door to the trailer (or out a window). You would get a lot of flies in the trailer using it

Bob

[The Colonel]

Think you said before that with wiring disconnected at power panel nothing happened, as it should. If so your wiring from inlet to power panel is likely good. As you said with neutral and ground connected you have problems. I suggest disconnecting converter to get it out of equation. Systematically remove a lead from the neutral bus and see if anything changes. If not do same with ground bus. I think you're looking for a bleed between the two. There may be better ways to isolate

[AirstreamJim]

Uncle_Bob: I won't be hooking up to AC power until this is fixed. I have visions of our Silver Meteor going down in a ball of fire. <shudder> We'll charge batteries with solar or if there's no sun, I'll bring my 10 amp car battery charger with us. We'll camp with battery power alone.

Good point, Colonel. I've had the converter's neutral disconnected for all but the last time I tried, with the shore power inlet removed. However, you make a good point about no issue with everything disconnected at the panel. I'm going to see if I can find me an electrician willing to look at it and try to determine where the neutral and ground are finding each other.

Jim

[ITSNO60]

Never mind I failed to carefully read your latest post.

[AirstreamJim]

[EDIT: Written in response to ITSNO60 before he edited his post away.]
This is something I will have an electrician do for me. However, I have two completely different shore power cord sets and it trips the GFCI with both. Based on that I had eliminated the shore power cord set as the problem. Am I wrong to think it's not the cord set?

Jim

[ITSNO60]

If you have an ohm meter you cal pull all the neutrals and all the grounding wires. Check for continuity between every neutral wire and between every neutral wire and grounding wire. There should be none as long as every one of them is floating and not touching the enclosure. When doing this test unplug any appliances.


Your neutral bus in the cabinet is floating on plastic with no contact to the enclosure correct? And following your thread it appears the problem got much worse correct? Did it get worse only after landing that floating ground wire?

[AirstreamJim]

Originally Posted by ITSNO60

If you have an ohm meter you cal pull all the neutrals and all the grounding wires. Check for continuity between every neutral wire and between every neutral wire and grounding wire. There should be none as long as every one of them is floating and not touching the enclosure. When doing this test unplug any appliances.


Your neutral bus in the cabinet is floating on plastic with no contact to the enclosure correct? And following your thread it appears the problem got much worse correct?

Excellent post - I've never done this kind of thing so the instructions are very helpful. Thanks! I will get an ohm meter and do this.

That was to be my next step tomorrow - verify nothing is deranged inside the cabinet. It all looks ok but I haven't done a really thorough inspection yet.

Yes, at first there were only two breakers that tripped the GFCI and then overnight all breakers cause the GFCI to trip. I do not know why it worsened.

Jim