Polarity Reversed/Ground fault

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After checking out Jeffery Raymond’s post on Electronic Gizmos, I figured I’d share a persistent issue I’ve been facing, hoping for some feedback or ideas.

Occasionally, when connected to shore power, my computer chimes in with a notification saying that there’s reversed polarity along with a ground fault issue. My electrical gauge panel echoes this with “Reversed Polarity” and “Ground Fault” warnings. The first time this happened, I panicked a bit, but after a quick check, I confirmed that the polarity throughout the coach was correct. I tested all outlets, inside and out, and everything seemed fine. Oddly enough, this has been a consistent issue at multiple campsites, as well as back home, where the electrical setup is reliable.

I thought I had this figured out until recently. While running off the generator, completely disconnected from shore power, the same “Reversed Polarity” and “Ground Fault” indicators lit up. And now, I’m scratching my head!

Every time the lights come on, they aren’t fully lit—ranging from faint to moderately bright, and they fluctuate in intensity.

Anyone else run into something like this? Would love to hear some thoughts!

[MyPrevost]

Here’s my two cents:

If I’ve got this right, you’re seeing an “idiot light” warning for reversed polarity and a ground fault, but when you check things yourself, you’re not getting any confirmation from your handheld tester. What kind of device are you using? Is it a meter, or one of those little plug-in gadgets where you read the LED indicators?

Just tossing out a wild guess here—might be worth (with all systems powered down, of course) checking the connections in your transfer switch. You’ll also want to inspect the actual physical connections where the shore power cord terminates in the electrical box (depending on how your converter is wired up). The dim and flickering lights could be pointing to loose connections.

Another idea—give your converter’s support line a call (many offer free assistance!). They might be able to help you identify the component that’s detecting these issues, in case it’s a faulty sensor. Different converters handle things in their own way, but companies like Marathon are pretty helpful over the phone for troubleshooting, and I’m sure others are too.

Good luck!

[MyPrevost]

Jim,

GFCI devices can be incredibly sensitive to ground issues, including things like corrosion.

Not sure of your coach’s full background, but if it’s spent time in an area where corrosion could be a concern—like near the coast—it might be worth taking a closer look at the condition of your ground connections.

[MyPrevost]

Jim,

I’d recommend shutting down all AC power in the coach, including the inverters. Once everything is off, start by removing the panel cover for the generator transfer switch and begin tightening connections, working your way through the coach.

I’m willing to bet you’ve got a loose or dirty connection somewhere, and that switch is a good place to start. Check every panel, from the breaker box to behind the metering panel (if you have one), and throughout the coach. Some setups have electrical panels above the entry door, in the first bay, and on the right-hand side of the second bay, plus the transfer switch behind the generator. With everything powered down, you won’t have to worry about any shock risk while you’re inspecting, but still, double-check each connection with a tester to make sure you didn’t miss an inverter switch or AC cord.

If all else fails, it might be an issue with the onboard computer that your system uses. It could be a loose connection, a faulty IC, or just a poorly seated IC. Isn’t this a fun puzzle?

You could try reaching out to your service team for help, but I wouldn’t hold my breath waiting for a quick fix.

Mike

[MyPrevost]

Jim, since you’re seeing the signal even on generator power, the issue is definitely onboard. You’ll want to take a close look at the neutral and ground connections in the transfer switch, as you’re experiencing the problem both when plugged into shore power and when running the generator. Additionally, if there’s a chassis ground from the transfer switch to the frame, make sure there’s no corrosion at the connection point. The neutral and ground wires should be connected to the same bus bar either in the transfer switch itself or at a disconnect switch before the transfer.

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Thanks Everyone for all the input. I will put on my Electrician Hat this week end and go to work !

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Jim,

Definitely take Mike’s advice seriously and make sure your inverters aren’t supplying any power. Disconnect the batteries or take other precautions to ensure you won’t get an electric shock while working.

Even if a meter shows the circuit as dead, keep in mind that inverters don’t supply power unless there’s a load, so relying solely on a meter might not be the best way to confirm the inverters are off.

[MyPrevost]

Jon, thanks for the info—I wasn’t aware that inverters don’t supply power unless there’s a load. I guess I could’ve ended up being “the load” in this case! I’ve been in the transfer switch box and other electrical junctions before. Country Coach used aluminum wiring in both the transfer switch box and the main breaker box, and I’ve regularly tightened connections—sometimes needing three or even four full turns per screw.

I agree with Warren that the dim warning lights likely indicate a ground issue, but I still haven’t tracked down the bad connection. I’m considering making a 10-gauge jumper wire with clips on each end, so I can try grounding different components while the system’s powered up to see if the warning lights go out.

I’ve spoken with Country Coach’s Tech Support multiple times, and they keep suggesting it’s a circuit board or processor failure. My approach, however, is to figure out if these lights are giving accurate warnings. It might be that there’s an issue, but it just hasn’t fully surfaced yet.

99 Country Coach 45XL
Jeep Liberty

[MyPrevost]

You definitely don’t want to end up as the inverter load! If I were tackling this, I’d start by cutting off all power, then open everything I could and begin cleaning and tightening connections.

Loose electrical connections are a pretty common problem—not just with our buses, but with anything electrical. In my business, we’ve shipped thousands of electrical boxes like the ones used in campgrounds, and despite each terminal being torqued with calibrated tools, customers still reported loose connections upon arrival.

Once you’ve cleaned and tightened everything you can, check for resistance before turning the power back on. Don’t rule out loose or corroded connections on any of the boards either.

Trying to diagnose this with the power on is risky, and it’s definitely not the safest approach because you’ll have a lot of electrical components exposed. Personally, I’d rather play it safe!

[MyPrevost]

Jim, if Country Coach suspects the board is at fault, one way to confirm this—similar to troubleshooting CNC machines—is by swapping in a known good board.

As I’ve mentioned before, tightness is an ongoing issue that needs regular checks. I had an incident where all the screws were tight, but the terminal was poorly tapped, which caused the wire to be loose. So, give the wires a good wiggle to check for any looseness, not just the screw itself.

You also mentioned the aluminum wiring and having to tighten it several turns. It’s possible the wire is getting too compressed and thinning out at the terminal from repeated tightening, which could reduce its ability to carry the load. With aluminum wiring, I believe it’s recommended to apply an anti-corrosion or oxidation-limiting coating (though I’m not 100% sure on this). You might want to consider using something like Corrosion X in this case. Personally, I’m not a fan of aluminum wiring and would replace it if it’s manageable to do so.

One more safety tip—before diving into any poking around, make sure to run a heavy-duty jumper wire to ground, just to stay on the safe side!

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Thanks to everyone who contributed to this thread. It turned out to be a loose main ground wire on a bus bar under the dash, along with a pin connector behind the electrical panel above the entrance door. Fixing one of these connections resolved the voice processor errors, while the other took care of the dim warning lights. It’s such a rewarding feeling to track down and fix problems like this!

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Great job, Jim!

Electrical issues can be tricky and often leave you feeling like you’re close, only to realize you’re way off. Glad to hear everything worked out for you in the end!

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Way to go, Jim! It’s incredible what a group of “asylum escapees” can come up with during their moments of clarity.

Just imagine the cost if you had handed this over to the converter or Prevost to troubleshoot and fix—would’ve been quite the bill for all that searching!

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I got some good news from the generator repair today, but I don’t fully understand what was wrong.

I was told there was an issue with the field and magnets, and the technician had to “FLASH” it, along with doing some serious cleaning. Now everything is working fine.

Could someone explain this to me in simple terms? I’m no electrician!

What I do know is that it won’t end up costing me a whole lot.

[MyPrevost]

I can relate to that; I know a bit about the process.

In my plane, I have a standby generator that acts as a backup to my alternator. As part of my pre-flight checks, I always test its operation. There have been times when it didn’t function properly. When that happens, I connect the wires directly to the battery in reverse polarity, and with a switch in the circuit, I give it a quick shot of juice. This is known as “flashing the generator.”

Usually, that’s all it takes to get it working again.

I assumed I was essentially re-magnetizing it.

And no more tough questions, Joe—I’m running low on my supply of made-up answers!

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