GFCI question

[JMCFAN]

I have a 2000 Jayco Designer that, when I plug into a GFCI outlet, pops it...  but if I run a cord to my other garage where no GFCI outlet is it is fine...    Had a freind over with his 5th Wheel this weekend and he as able to plug in so its not the outlet...

Where should I start???

 

[Ned]

I would suspect a short between the neutral and ground wires in your RV.? Do you have an inverter?? Often the neutral and ground will be connected, incorrectly, when an inverter is installed.? It's also possible that there is a high resistance short between either the neutral or hot to ground somewhere in the RV as well.? One way to isolate the problem is to disconnect each circuit at the load center (you may have to remove the breakers as well as the neutral wires), then reconnect them one at a time until the GFCI indicates a fault.? Do the disconnect and reconnect WITHOUT power connected to the RV.

Others may have some other troubleshooting techniques.

 

[JMCFAN]

Yes I have an inverter.  I am 2 weeks from a 2 week tour ( NM-> ARK->Wis;>Yellowston( ;D) Mohab->NM  Will this cause issues at RV parks...  ?  Everything works fine when not connected to a GFCI breaker...

 

[Carl L]

Yes I have an inverter.? I am 2 weeks from a 2 week tour ( NM-> ARK->Wis;>Yellowston( ;D) Mohab->NM? ?Will this cause issues at RV parks...? ??? ?Everything works fine when not connected to a GFCI breaker...

You have a ground fault somewhere in the 120VAC system of your RV.  Chase it down and correct it before you starting living in the RV. 

 

[Ned]

I would start with the inverter circuit.  It's the most likely culprit.

 

[JMCFAN]

Here may be another hint....I occasionaly pop the 30 amp blade fuse at the batteries.... ???

 

[JMCFAN]

Okay....I am wrong...  I DO NOT have an invertor....only a converter ( I think...? ) No AC power from batteries...  only DC  from AC....

Now any ideas on where to start...??

 

[Ned]

Isolate the problem as I described by disconnecting all of the AC circuits at the load center.  Connect one at a time until you see the fault.  If the fault occurs with all circuits disconnected, then the problem is between the load center and the shore power connection.  There is no easy way to diagnose this.

Also, unplug all appliances too.  It's possible that the leak is in one of them.  Since that's the easiest to check, start there.

 

[John From Detroit]

Okay....I am wrong...  I DO NOT have an invertor....only a converter ( I think...? ) No AC power from batteries...  only DC  from AC....

Now any ideas on where to start...??

Step 1, Turn off and/or unplug EVERYTHING,  Set all breakers in the MH/Trailer to OFF, does it trip the GCFI?

NOTE: if possible unplug the 110 to 12 volt converter.  If the GCFI holds plug in a lamp and activate the breaker that controls it. If the GCFI holds you are in business for diagnosis, one at a time bring up all the breakers, if the lamp goes out, shoot that circuit, it's deffective, I do not expect the lamp to go out at this step however, 

I should add here, I'm going way overboard and checking things most likely not bad, but when shooting trouble that may well be hidden in a wall... You do all the easy steps even if they are guarenteed to not help

Now plug things in,,, starting with the converter/inverter. if/when the lamp goes out shout EUREKA for you have found it

Next turn things on... Again if the lamp goes out,,, Shout EUREKA for you have found it

Many trailers however have ground (Green) and nuteral (White) hooked together, this will trip a GCFI.  There is nothing technically wrong with doing it this way so long as you don't get a backwards wired cord (I had that problem with my old trailer, the previous owner had home brewed an adapter for the power inlet, he'd wired the black wire to the shiney screw and the white wire to the copper screw.  That trailer would knock you on your .... You know what,,, if you used a commericial extension cord to power it, Using his cord (of course) no problem since he'd wired it the same way.  I fixed both of them.  I'm cross trained electronics/electrical,  In Electronics black is ground, Same for automotive electrical (how he was trained) but in 120/240 vac black is HOT white is not, and green is ground, or at least that is the standard (White is grounded at the breaker box)

You may also have green and white connected together at the breaker box

If the problem is "internal" (not something plugged in) I'd strongly suggest a professional to fix it

 

[JMCFAN]

You guys rock!  ;D ;D I will get to testing tonight!

 

[Ned]

Many trailers however have ground (Green) and nuteral (White) hooked together, this will trip a GCFI. There is nothing technically wrong with doing it this way so long as you don't get a backwards wired cord

Technically, that is wrong.  The ground (green) should be isolated all the way back to the system ground point with no connection to the neutral (or anything else).  I agree that is the most likely cause of the problem, that the ground and neutral are tied together somewhere in the RV wiring.  A quick test for that is to remove the ground wire from the shore power feed, so there is no connection to the grounds in the RV, and see if the problem goes away.  If so, then at least you know there is no leakage between the hot and neutral.  That can make for a dangerous situation, a ground-neutral connection won't kill you.

 

[John From Detroit]

Technically, that is wrong. 

Yes, I know, it's wrong, don't mean a lot of trailers, espically older trailers, were not wired that way though.

How to fix it,,, that I do not know.

Which is also why I recommended professional help

 

[Ned]

Yes, professional help is advised is you don't know what you're doing around electricity.  Troubleshooting 12V problems is a lot different than 110V problems.

 

[JMCFAN]

Thanks all for the input and help..... I am actually a EE by degree....but have been in the semiconductor biz for 14 years......  I really wanted some help from those that have delt with stuff.... which I got..      I wont fry myself.....I promise.. ;D

didnt get to it tonight....damn work.. :'(..  tomorrow for sure

 

[Ned]

Let us know what you find.  Your problem is not uncommon in RVs and the solution may help others.

 

[JMCFAN]

Okay got it!!

Turned off all breakers and unpluged convertor- OK
Turned on AC- OK
Turned on Utility-OK
Turned on Kitchen- OK
Turned on microwave- OK
Turned on Water Heater-  POP!
Turned water heater breaker off and plugged in convertoe- OK

took off the box on the inside and disconnected the element and checked with a meter- OPEN.

Looks like I poped a heating element....

Now I just have to find one.....will call dealer tomorrow.

Hope I can get one in a week and 1/2... :-\

 

[Ron]

Sounds like you found the cause.  Hope getting the needed parts is as easy.

 

[Ned]

It's more than just an open heater element.? You have a short in that circuit, probably between the neutral and ground wires.? Remove all the wires to that circuit, hot, neutral, and ground, and check for a high resistance between any of the wires, especially to ground.? You'll need to fix that as well.

Of course, the short could be in the element, so check that too.  If it is, then replacing it will solve the problem.

Glad it was easy to isolate.

 

[JMCFAN]

Ned, I had a guy on the Ford Diesel web page  tell me he had the same problem and the element fixed it.  Now, should I check to see if the element has blown and shorted to ground  is that what you think would cause it?

He left his heater on with no water in it....which I could have done.... :-[

 

[Ned]

Yes, if it shorted to ground that would most definitely cause your problem.  Did you check with the element disconnected other than check it for continuity?  If the problem goes away with it out of the circuit, you're done.  If not, then further checking is required.  I suspect the element is the problem, however.

Replacements should be available at any decent sized RV store.