Polarity Reversed/Ground fault

[JIM KELLER]

After reading Jeffery Raymonds Thread in Electronic Gizmos I decided to post my on-going problem for review and possible support.

Intermittently, while plugged into shore power my computer announces that the polarity is reversed and a ground fault problem is occurring. Lights on my electrical guage panel also state " Reversed Polarity" and "Ground Fault." The first time it happened the stress factor was HIGH until I determined the polarity was correct through out the coach. I used my tester on all outlets inside and out and found no problems. The same thing happens at all the campsites and at our home where the electrical is known to be good.

I thought I had a handle on the problem untill yesterday. While running the Generator and unhooked from shore power the "Reversed Polarity" and "Ground Fault" lights came on. Now I am stumped !

Each time the warning lights come on they are never fully illuminated. The brightness ranges from dim to medium bright and changes in intensity.

Any one have any ideas ?

[jello_jeep]

My .02

If I understand, you are getting an "idiot light" indication of reverse polarity, and a ground fault. However when you check manually you have no indication from a hand held type checking device. Is this a meter? Or one of those dealies you plug in to an outlet and decipher the leds?

As a shot in the dark, you might want (with all power removed from all systems) to check the connections in the transfer switch. Also check the physical connections, where the shore cord actually terminates into the electrical box (depending on converter as to how it actually is hooked up). The faint indicator lights hint of loose connections to me.

You might also call your converter (free!) and they could point you to the device that senses those conditions, maybe it is malfunctioning? Each converter does things differently, and at least Marathon is helpful on the telephone in troubleshooting, and I would imagine the other converters are as well.

Best of luck.

[Jon Wehrenberg]

Jim,

GFCI devices are extremely sensitive to ground problems such as corrosion.

I don't know the history of your coach but if it was located in an environment where corrosion could be an issue such as near the coast, it might be worth checking out your ground connections.

[mike kerley]

Jim, I'd kill all the AC power in the coach including shutting down the inverters. Pull the panel cover where your generator transfer switch is located and start tightening from there through out the coach.

I'll bet a quarter you've got a loose or dirty connection and I'd start looking at that switch. Check every panel from the breaker box and behind the metering panel (if you have one) through out the coach. Our CC has a large electrical panel above the entrance door, in the first bay and on the r/h side second bay plus the transfer switch behind the generator. With all the AC dead, you dont have to worry about getting bit while probing around, but still check each connection with a tester before you touch it, just in case you missed an inverter switch or ac cord.

As a last resort it could be the on board computer that CC uses. It may have a loose connection or a bad IC or just a loose IC. Isnt this fun!?

CC service may offer some help, but I would'nt hold my breath waiting.

Mike

[garyde]

Jim, since you are getting the signal on Gen power, it is a problem on board. Inspect your nuetral and ground connections at the transfer switch since you are experienceing the problem both when plugged into shore as well as when on generator. Also, if there is a chasis ground from the transfer switch to the chasis , verify there is no corrosion at that point of connection. The nuetral wires and the ground wires should land on the same bus bar at the transfer switch or a disconnect switch before the transfer.

[JIM KELLER]

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

[Jon Wehrenberg]

Jim,

Pay close attention to Mikes suggestion and make sure your inverters are not putting out power. Disconnect the batteries or do something to insure you do not get an electrical shock.

Checking the circuit with a meter may show the circuit to be dead, but inverters will not supply power if there is no load, so a meter is not necessarily the best way to verify the inverters are not supplying power.

[JIM KELLER]

Jon, Thanks, I did not know that Inverters don't supply power unless there was a load. Perhaps I could have been "the load." I have been in the transfer switch box and other electrical junction areas before. Country Coach used aluminum wire in the transfer switch box and the main circuit breaker box. I have rountinely tightned many conections three and sometimes four turns per screw. I do agree with Warren that the dimness of the warning lights point towards a ground type problem. I just dont think iI have found the bad connection yet. I am think of making a 10 ga. jumper wire with clips on each end and trying to ground different components while energized to see if I can make the warning lights go out.

I have talked to the Tech Support Dept. at Country Coach and each time they have the theory that a circuit board or processor has gone bad. My theory is to see if the lights are telling the truth. Perhaps there is a problem, just not full blown yet.

[Jon Wehrenberg]

You definitely do not want to become the inverter load. If I were to attack the problem I would kill all electric, open everything up that I could, and start cleaning and tightening.

Loosening electrical connections is a common issue, not only with our buses, but anything electrical. In our business we shipped thousands of electric boxes such as the one we plug into in campgrounds and despite each connector or terminal being torqued using calibrated production tools there were issues with loose connections when the units were received by the customer.

After you have cleaned and tightened all the connections possible you can check for resistance before turning on power. I would not rule our loose or corroded connections on any boards.

Checking things with the power on is the least acceptable way to do this because of the potential for injury. You will have to have a lot of the electrical stuff exposed. I'm a chicken.

[JIM CHALOUPKA]

Jim, If the board is suspect as indicated by Country Coach, then as in CNC machines the way to find out is by swapping a known good board.

To repeat one of my earlier posts the tightness is an issue that needs to be checked regularly, but as one incident I had the screws were all tight but the terminal was miss tapped and the wire to it was loose. Wiggle the wires as an indication of tightness as well as tighten the screw.

You mention Aluminum wire and that at times you had several turns to tightness, well maybe there is something going on here where as the wire is getting too compressed and thin at the terminal if you will. Maybe the wire can not carry the load due to a reduction in size from repeated tightening. Further I believe that with aluminum wire it is recommended to use an anti corrosion or oxidation limiting coating ( not 100% sure on that). Perhaps the use of corrosion X is appropriate here? I personally don't like Aluminum wiring and would change it out if there is not too much.

Another safety precaution is to after everything else that has been said run a heavy duty jumper wire to ground before you start poking around!