Electrical Problem, dangerous or safe?

[wmtire]

Originally Posted by FollowTheSun

Most home AC electrical devices/appliances are powered by two wires, a hot (power, usually black) wire and a return (neutral, usually white) wire. A third ground wire is added for safety, and under normal working conditions shouldn't be conducting any current. Your microwave oven, for example, only needs the power wire and neutral wire to function. Measured current (amps) on the black wire will equal the measured current (amps) on the white when the microwave is working. There is something seriously wrong if the two currents are not equal. Unequal or unbalanced current means that an additional current or current path has been introduced to your device, usually through a malfunction. Because such malfunction could cause electrocution (death) a ground wire is introduced providing a low-resistance path to ground. In a home (the one with a concrete foundation) all those white (neutral) wires and green (ground) wires are tied together inside the breaker box.
The GFCI is a device that looks at the current in both the power & neutral lines, and switches the circuit off if the two currents are not equal, the ground wire is actually ignored. Technically, the term GFCI (Ground Fault Circuit Interrupter) is a little inaccurate because the ground wire is ignored. However, its safety feature is very accurate because it detects the current imbalance that is a particular safety concern. But here also might be an issue associated with RV power systems. For example, if the RV breaker box were to tie the neutral wires and ground wires to each other then the balance between power and neutral current will be disrupted because the return path current, as measured on the RV shore-power cord, now has two paths (neutral & ground). If the shore-power is plugged into a GFCI outlet, the GFCI will trip because half the current flows through the white wire and the other half flows through ground (simplified illustration) creating an imbalance between the black & white wires.
Folks might notice that RV shore-power boxes do not have GFCI on the 50-amp or 30-amp service, only on the 20-amp (or less) service.

Just to clarify a little, the neutral is the grounded conductor.

This may help explain the difference between grounded and grounding.

https://c03.apogee.net/mvc/home/hes/...c=foe&id=17569

[WY Husker Fan]

It tells you there is nothing wrong from the end of the cord to the power center. If the breaker for the water heater is labeled and you can identify the cable going to it you can disconnect the white wire of that cable from the neutral bar and check for continuity between that and ground. I like others suspect that as the most likely issue. Even with all breakers off, if your water heater element is burned out, there is a high likelihood that it could be shorted to ground which would essentially connect the ground and neutral together which would trip the source GFCI.
I would also get a new cord end for you supply cord and replace it based on the evidence of overheating shown in earlier pictures.

[Sleepy]

Good Morning:
I unplugged the water heater from outlet.
I identified and removed the neutral wire from the neutral bus bar.
I checked continuity between neutral wire and ground wire and there is no continuity.
With the water heater unplugged from the outlet, it immediately trips GFIC outlet when plugging into 15 amp outlet. Then I tried plugging it in with the hot water heater neutral wire removed from neutral bus bar and again it immediately tripped GFCI.

Then, with the hot water heater unplugged from outlet, the neutral wire from hot water heater removed and isolated still, I again checked for continuity at the plug end of the cord, and I still have continuity between neutral and ground at the plug end.

Would I assume this isolates the water heater out of the equation and would not be the problem?

Any ideas at this point as to what the culprit would be causing this? Again, it only trips on a GFIC 15 amp outlet, not the standard 30 amp rv plug (non-GFIC).

[FollowTheSun]

As Grumpy7159 stated: "You should not have continuity between the neutral and ground." This is why the CGFI is tripping. An RV AC electrical system is considered a "sub-panel," as such neutral and ground should have no continuity between them while disconnected from shore power. Something in your unit has connected to two together.

To troubleshoot / isolate:
Referring back to your photograph of the electrical panel.
1. Disconnect shore-power cord.
2. Connect continuity tester (ohm meter) between the electrical panel ground bus and neutral bus (because of your fault, this will measure continuity).
3. Beginning at one end of the neutral bus bar, remove a white wire and check continuity.
4. If you still measure continuity between the two bus bars, then continue to the next white wire.
5. If you longer measure continuity, then you have isolated the problem circuit. Match the white wire with its companion black wire and the associated breaker to identify the circuit.
6. Re-connect the previously removed white wires (except for the faulty one) and re-test continuity (to insure only circuit is affected).
With the faulty circuit identified, you may need to continue tracing the circuit to locate the specific cause.

[FollowTheSun]

After looking closely at your photograph, I notice a bare ground wire running near the neutral bus bar. I can not tell from the photograph, but it almost appears that the bare wire might be touching the neutral bus. If it is touching, then this might be the problem. Check to be sure the bare wire is not touching the neutral (white wire) bus bar.

[Sleepy]

This has been a productive and confusing step for me.

I followed your excellent suggestion and the first neutral wire I removed was the guilty party. Then it gets confusing for me.
I followed this wire, and the neutral wire goes to the electrical outlet then on to other unknown items in the wall of the trailer. I don't know how to determine to what else that goes to. I would assume other outlets, but I do not know how to determine that with my tester??
The hot wire from that same wire traces back to the second breaker labeled as "General". Before reaching the breaker, it is joined with a yellow wire nut and goes to the second breaker where there is a union at the breaker with a second black wire that goes to the converter. The converter has its own separate white neutral wire going back to the neutral bus bar.

After opening the back of the first outlet it goes to, I again tested for continuity between this guilty neutral wire and the ground bus bar, and it no longer has continuity. I tested for continuity between the black wire and neutral and have none. But for some reason, I no longer have continuity between the guilty neutral wire and ground once isolating this neutral and hot leg of the outlet wire.

I then went out to the trailer plug, and tested for continuity between the ground lug and the neutral lug, and there is no longer continuity with this wire removed. Hopefully the pix will explain better than I can. Anyone have a wiring diagram for this camper? 2003 Forrest River Wildwood 24 ft.
Thank you.

[FollowTheSun]

I think "General" implies that this circuit supplies all of the outlets, and (if I understand you correctly) also your converter. Also, to be sure I understand: are you saying that the black wire is spiced with the yellow wire nut before completing its run to the breaker?
If the problem appears to have gone away, then I suggest you return everything back to as it was before you began this test process and re-check the continuity between the ground bus and the neutral bus.
If there is no continuity and the problem seems to have fixed itself, then we should consider that simply jiggling the wires somehow "fixed" it. I notice in your second series of photographs that the ground wire, which I questioned, has been moved a little from where it was in your first set of photographs (see attached photo). Could this wire have been touching the neutral bus and got moved when you pulled the white wire? That wire could have caused your problem if it had been touching.

[pmurph991]

Originally Posted by Sleepy

Good morning :
I removed the incoming green ground wire from the cord at the ground bus bar, and now I have no continuity between the ground and neutral lugs or terminals on the plug. See pix hopefully attached. I’m not sure exactly what this tells me. I taped off the end of the ground wire prior to testing. Thank you.

What it tells you is the short from ground to neutral is NOT within the cord. You could disconnect 1 white wire at a time to find out which one is giving you continuity between whit and green. Then follow white to cable it is in to identify which black wire (circuit) it is.

[Herk7769]

Not mentioned (I think) is the possibility that a wire has come loose from the rear of the socket on the camper.

[Sleepy]

I typed up a detailed step by step earlier, but I guess something went wrong because I am not seeing it here. I apologize for the delay.
I will attempt to give the short version.
The continuity check showed an intermittent fault. It would appear that the first electrical outlet may have been the source of the problem. Since it was intermittent, it may reappear, but I replaced the outlet with a standard electrical 15 amp outlet and narrow outlet box. I reassembled the outlet in the wall and retested the continuity and it would appear the issue was corrected with the outlet replacement. I plugged the cord into the adapter and then into the 15 amp GFCI outlet, and it did not trip the ground fault. This was a great change.
I hope the solution is definitive.

Please allow me to say what wonderful help all of you have been. I learned a lot, and enjoyed the process and hopefully in the future be able to apply what I have learned here.
I hope I may be able to return the favor in the future. This is a great group.
Thank you.

[FollowTheSun]

Sleepy ... Great News! You seemed to have nailed it. Now it's time to go camping. Good luck.

[pmurph991]

Glad you found the solution!

[Grumpy7159]

Send the new cord back if you don't want to replace it.

[Sleepy]

Yes, finally time to start cleaning and stocking.

I will replace the cord, it should arrive while Im gone, but I will install that on my return just to be safe, and keep this one as a "back up".

Hope to see you in the campgrounds.

[ewinterbee]

Glad you got it fixed. I do think for the little work involved, you might want to shorten that bare ground wire that runs over the top of the white wire buss bar and reattach it away from the white wire bus bar, just as extra precaution.

[Sleepy]

That’s a good idea and thank you for the great suggestion.

[Invisibleman]

You will always have continuity between ground and neutral because they are tied together at the service entrance point. A GFCI separates those and measures the difference between the two. It sounds to me like you may have two GFCI's in the same circuit fighting each other. You don't need, not should have any GFCI to plug in your shore power so not sure where this GFCI thing is all about. Although I must admit, I didn't read a whole lot of this thread. Im a master electrician in two states with 40 years experience. All I can say, is if something keeps tripping, figure it out, instead of keep resetting it. There is always a reason.

[Sleepy]

Invisibleman:
Honestly, not being an electrician, it is confusing to me the whole neutral and ground and how some feel I should and some feel I should not have continuity between the ground and the neutral on the plug.
I wont fully understand this most likely not being an electrician, but would love to better understand the "why" I should or should not have continuity between the two legs.
Please share with me any information that would help me to better understand as a layperson.
I value and appreciate any and all input. If a professional with your vast amount of experience would be kind enough to share valuable information, I would appreciate your input.
Respectfully

[dmwoody]

Originally Posted by FollowTheSun

As Grumpy7159 stated: "You should not have continuity between the neutral and ground." This is why the CGFI is tripping. An RV AC electrical system is considered a "sub-panel," as such neutral and ground should have no continuity between them while disconnected from shore power. Something in your unit has connected to two together.

To troubleshoot / isolate:
Referring back to your photograph of the electrical panel.
1. Disconnect shore-power cord.
2. Connect continuity tester (ohm meter) between the electrical panel ground bus and neutral bus (because of your fault, this will measure continuity).
3. Beginning at one end of the neutral bus bar, remove a white wire and check continuity.
4. If you still measure continuity between the two bus bars, then continue to the next white wire.
5. If you longer measure continuity, then you have isolated the problem circuit. Match the white wire with its companion black wire and the associated breaker to identify the circuit.
6. Re-connect the previously removed white wires (except for the faulty one) and re-test continuity (to insure only circuit is affected).
With the faulty circuit identified, you may need to continue tracing the circuit to locate the specific cause.

If there is a lever box SHORE-OFF-GEN before the breaker panel, is that a sub panel as well? I see the green bonding screw in that switch box. I too trip GFCI shore outlets when plugging in with a 15a extension cord and adapter. Does the gen need that box to have the bonding in it?

[doanshop]

Originally Posted by Toddupton

Don’t bother, you can look at the melted cord and by the reading you gave the cord is bad. Have you been running your air conditioning while being plugged in with the adapter?

That was the same thing I thought most times people run a/c with 15 amp adapter and it over heats . And they use a small extension cord .