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GFCI tripping issue on house


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Bear with me while I explain this.

I have not moved my fifth wheel in a while and have a 100ft 14AWG extension cord running from the shore power cord to a GFCI outlet on my house to run an oil-filled free standing heater in the camper. I have had it set up this way for over two months and have not had an issue. As of last Sunday this set-up is tripping my GFCI outlet anywhere between 2 hours and 14 hours after being plugged in. It never trips immediately.

I have not added or detracted from my electrical components on the 110V circuit except for a new breaker (a month ago), and my inverter is not yet wired in. The only recent things I have done have nothing to do with electrics and I have added nothing onto the walls. I have nothing else running and all other breakers are in the Off position. I have been able to run the heater on high, lights and TV/PS3 console all at the same time up until this point.

My camper GFCI outlets and the regular outlets are on two separate circuits and breakers and plugging the heater into either one causes the same tripping of the house GFCI. Nothing trips in the camper.

I have tried a different extension cord, different 30-15A plug converter, different heater, different outlets (GFCI and regular circuits), different GFCI outlet on the house and still it trips. The 30A plug and converter plug are protected from the weather in one of the wheel wells. I have plugged the heater directly into the extension cord from the house through a window and it does not cause the GFCI outlet to trip.

I realize that this means there is an electrical issue somewhere but this has me completely stumped. I did have a few leaks in the bathroom (which are now fixed and were mostly dried up immediately. Is it possible some of the excess water, plus all the moisture we've been having got into the circuit somewhere? The shore power cord is in the panel between the living area and the bathroom.

2007 Keystone Springdale 245 FWRLL-S (modified)

2000 F-250 7.3L SRW

Cody and Kye, border collie extraordinaires

Latest departure date: 10/1/2017

 

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I tried two separate GFCI outlets, and the outlet is fine if I plug the heater straight into the extension cord and by pass the 30A shore power plug and cord

2007 Keystone Springdale 245 FWRLL-S (modified)

2000 F-250 7.3L SRW

Cody and Kye, border collie extraordinaires

Latest departure date: 10/1/2017

 

Find us at www.nomadicpawprints.wordpress.com

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It is possible that the problem is in a connection that warms up with use and so begins to leak a small amount of current. Most of them will trip with a loss of .006 amps which isn't very much. Some weakness in insulation or perhaps a carbon trail could cause this. From what you say I would suspect the wiring in the bathroom walls or somewhere that might have been exposed to the leaks. You probably will not find anything visible so try reconnecting and junctions or splices. It probably will not be easily found.

Good travelin !...............Kirk

Full-time 11+ years...... Now seasonal travelers.
Kirk & Pam's Great RV Adventure

            images?q=tbn:ANd9GcQqFswi_bvvojaMvanTWAI

 

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  Here's the deal. If a GFCI trips, its caused by EITHER:

  a) The GFCI is at fault (happens fairly often especially if a cheap big box store unit) or

  B There's a ground fault of at least 6 milliamps. IE the current flowing out the Ungrounded Conductor is 6 milliamps MORE then that being returned by the Grounded Conductor BECAUSE ITS FLOWING ELSEWHERE IN ANOTHER (fault) PATH.

 Its not hard or rocket science to start substituting and eliminating devices to find the cause or location. This is accomplished by substituting cords, trying the heater plugged direct to the GFCI, plugging the heater into different outlets, plugging loads other then the heater into the GFCI and various other receptacles, I'm sure you already know or get the idea of systematic substitution and elimination to find the culprit/leaker device and/or the location of the ground fault. FROM YOUR POST IT SOUNDS LIKE YOU HAVE ALREADY DONE MOST OF THIS TYPE OF TROUBLESHOOTING and have eliminated many possible causes. If no faulty cords or devices or switches or receptacles or wiring faults can be found IM THINKING MOISTURE !!!!!

 The thing is 6 milliamps (0.006 AMPS) IS VERY SMALL so it doesn't take much moisture or corrosion or foreign material to return 6 milliamps in any available alternate path OTHER THEN THE GROUNDED CONDUCTOR. 

 If the GFCI itself is okay, the ground fault leak may be in the RV panel or interior wiring or receptacles but my first suspects would be circuits that lead outside or near water sources like in the bath or kitchen or exterior receptacles and/or wiring to those areas. It doesn't take much moisture to trip a GFCI. Insulation can have opens or cracks,,,,,,,,,,,switches and receptacle boxes can accumulate moisture,,,,,wiring can be frayed,,,,,,,,,,,,,,prior arcing faults/shorts may leave conductive carbon (look for evidence of past arcing or burning or high temperatures or shorts etc),,,,,,electrical devices can have an internal fault etc etc etc.

 If the GFCI trips when the load is plugged into a particular RV branch circuit but NOT others, you found the circuit at fault, so look for moisture or evidence of carbon or arcing or bad connections or bad insulation or faulty wires etc. BUT ESPECIALLY MOISTURE !!

 Again if the GFCI itself is okay, there's got to be a ground fault in the cord (including ends !!!!) or internal wiring or panel or receptacles especially in high moisture areas or an electrical device itself, and it looks like you already eliminated many possibilities.

 John T Longggggggggg retired EE and rusty on this stuff so no warranty  

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If this amateur calculated correctly, you have a 6% drop in voltage at the end of the 100', 14AWG extension cord, the maximum recommended is 3%; this does not consider your 30A trailer cord in calculations, or wiring in your RV. I suspect enough heat is generated somewhere to cause a faulty connection.  A 10AWG extension cord will bring you up into the safe voltage drop area, less than 3% drop.

Couple that with the fact GFCI receptacles wear out over time, even the high-priced ones, and you may have multiple factors causing it to trip.

 

 

2000 Winnebago Ultimate Freedom USQ40JD, ISC 8.3 Cummins 350, Spartan MM Chassis. USA IN 1SG retired;Good Sam Life member,FMCA ." And so, my fellow Americans: ask not what your country can do for you--ask what you can do for your country.  John F. Kennedy 20 Jan 1961

 

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Found a slightly loose ground wire in the junction box where the shore power cord switches to the trailer wiring. No moisture in the compartment itself but lots of twigs. Heater still running fine on GFCI house outlet with bypassing the trailer wiring so I know it isn't the heater, cord or outlet.

Will check other connections if I can get to them (might have to pull out the whole panel). Also going to clean the shore power plug since it is dull and try connecting other things to the trailer wiring that don't pull as much power as a heater (I'm thinking a fan would be sufficient) and see what happens

2007 Keystone Springdale 245 FWRLL-S (modified)

2000 F-250 7.3L SRW

Cody and Kye, border collie extraordinaires

Latest departure date: 10/1/2017

 

Find us at www.nomadicpawprints.wordpress.com

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Dune, just FYI, a GFCI sensing device does not measure current in the safety bare/green Equipment Grounding Conductor in order to trigger a trip or not. There are ONLY two wires (Hot and Neutral) that pass through a torroid coil. If the current flowing out the Hot is the same as that being returned by the Neutral no voltage is induced into the coil, BUT if the current flowing out is more then that being returned by the Neutral (because its returning elsewhere) a slight voltage is induced which trips the GFCI.

Hope this helps and doesn't confuse lol You are already undertaking a good substitution and systematic scheme to find the current leak.  

 Indeed dirt or moisture or carbon in plugs or receptacles or anywhere for that matter might allow for 6 milliamps of leakage current tripping a GFCI 

 

 John T

 

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I tightened or checked ALL connections, not just the bare copper ground wire. There are a couple of 12V fuse connections that need to be redone but those have nothing to do with the 110V system, especially without the converter on. They aren't bad, just not as perfect as I'd like them...just don't feel like unhooking the battery bank today with all the snow on the ground.

 

2007 Keystone Springdale 245 FWRLL-S (modified)

2000 F-250 7.3L SRW

Cody and Kye, border collie extraordinaires

Latest departure date: 10/1/2017

 

Find us at www.nomadicpawprints.wordpress.com

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7 hours ago, DuneElliot said:

Also going to clean the shore power plug since it is dull and try connecting other things to the trailer wiring that don't pull as much power as a heater (I'm thinking a fan would be sufficient) and see what happens

 

The fan won't draw nearly as much power at the heater, but it may be sufficient to do what you have in mind. Your heater is probably 1500 watts or would draw about 12.5a. Your fan on high may draw as much as 3 to 5a. 

Good travelin !...............Kirk

Full-time 11+ years...... Now seasonal travelers.
Kirk & Pam's Great RV Adventure

            images?q=tbn:ANd9GcQqFswi_bvvojaMvanTWAI

 

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Everything is still running this morning. The camper is plugged into a slightly shorter extension cord and has a few things running inside. The heater is plugged directly into the original extension cord. Both are plugged into the same GFCI outlet. Nothing has tripped in 18 hours.

Going to try plugging the heater back in to the camper today.

Found another leak which I though might be a culprit but there is no moisture anywhere near the wiring or outlet.

2007 Keystone Springdale 245 FWRLL-S (modified)

2000 F-250 7.3L SRW

Cody and Kye, border collie extraordinaires

Latest departure date: 10/1/2017

 

Find us at www.nomadicpawprints.wordpress.com

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You're getting there. Simple things like longgggggggggggg extension cords and even slight moisture or even minor interior appliance faults or even an aged or poor quality GFCI can cause a trip and many of those are simply NOT visible to the eye. Sure a GFCI on some circuits can cause nuisance tripping, but they have to be that sensitive (0.006 amps) by design and safety since it may only take 0.030 to 0.050 amps to mess up your ticker !!!!!!!!!!!!!!!!!! Sort of goes with the territory especially where moisture and RV extension cords are the norm.

 

 John T  

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Something very telling just happened. Had it all hooked up like my previous post.

Turned the heater from Min to Max. 5 minutes later GFCI tripped.

2007 Keystone Springdale 245 FWRLL-S (modified)

2000 F-250 7.3L SRW

Cody and Kye, border collie extraordinaires

Latest departure date: 10/1/2017

 

Find us at www.nomadicpawprints.wordpress.com

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Could be the straw that broke the camels back ??? With everything else removed and its ONLY the heater that does that, ya gotta either  1) Find n fix the leak (yeah right, good luck with that one lol)

           2) NOT use the heater on high (or toss it)

           3) Just for the heck of it Id try a new GFCI, they can go bad ya know

           4) Try a different cord. (if even using one, IE plug heater direct to GFCI if not already) 

      I've seen those strip element heaters where the coils are suspended and with heat and high current $hit happens

     If none of the above works, take two aspirins n call me Monday at the office.

    John T

  

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3 minutes ago, oldjohnt said:

Could be the straw that broke the camels back ??? With everything else removed and its ONLY the heater that does that, ya gotta either  1) Find n fix the leak (yeah right, good luck with that one lol)

           2) NOT use the heater on high (or toss it)

           3) Just for the heck of it Id try a new GFCI, they can go bad ya know

           4) Try a different cord. (if even using one, IE plug heater direct to GFCI if not already) 

      I've seen those strip element heaters where the coils are suspended and with heat and high current $hit happens

     If none of the above works, take two aspirins n call me Monday at the office.

    John T

  

Only the heater, and only on high. 

I did try the other GFCI....it tripped even quicker.

I have also tried several cords...same result.

2007 Keystone Springdale 245 FWRLL-S (modified)

2000 F-250 7.3L SRW

Cody and Kye, border collie extraordinaires

Latest departure date: 10/1/2017

 

Find us at www.nomadicpawprints.wordpress.com

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Water heater is not electric, and the breaker is off for that and the fridge currently since I don't need them...although do need to test them soon. It seems like it is just a combination of weird things.

2007 Keystone Springdale 245 FWRLL-S (modified)

2000 F-250 7.3L SRW

Cody and Kye, border collie extraordinaires

Latest departure date: 10/1/2017

 

Find us at www.nomadicpawprints.wordpress.com

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Modern GFCIs test for leakage between the neutral & ground.  Shutting off the circuit's breaker will not prevent this type of fault, so it could still be a problem with the fridge heating element.  If you can unplug it, that will be a good test.

If shutting off the branch circuit breakers doesn't identify a bad circuit, digging into the breaker panel and opening the neutrals one at a time is about the only way to check for neutral/ground faults. Might be more than a non electrician would want to get into...

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Please correct me if I'm wrong, but do I understand correctly you're talking about an "oil-filled free standing heater in the camper"

CORRECT????

If so, here's what I'm left with. If  possible, take the heater using its own cord and plug (NO extensions at all) OUTSIDE the RV and plug it DIRECT INTO a GFCI household outlet somewhere. If it still trips that GFCI on high its got an internal ground fault drawing at least 0.006 amps PERIOD. It could be the wiring or connections or moisture inside, darn if I know.

HOWEVER if it works fine outside totally free of the RV and any cords whatsoever, but still trips the RV GFCI when plugged inside the RV, THE FAULT IS SOMEWHERE IN THE BRANCH CIRCUIT (or RV Panel or extension cord or GFCI) THAT SERVES THAT RECEPTACLE............... 

Best I have to offer. Test it total isolated from the RV to see if the heater itself is at fault or something inside the RV

NOTE AND PS:  A GFCI "receptacle" looks for a leak in some device that's plugged into it orrrrrrrrrr in a downstream circuit or device fed off its LOAD side and NOT the entire house and RV mind you. This has got so long I cant remember what's plugged where anymore lol. The GFCI receptacle (NOT talking about a GFCI panel breaker) isn't gonna detect upstream leaks ONLY those that pass through its torroid coil current sensing device (if that's how they still work, see below)   This NOTE AND PS after thought may possibly void my HOWEVER paragraph above, but I cant remember if were talkin about a GFCI the entire RV plugs into or an individual GFCI where the heater plug direct or what SORRY.....   

John T

 

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25 minutes ago, vermilye said:

Modern GFCIs test for leakage between the neutral & ground

Yo Vermilye, I been retired from electrical engineering for years and this may be long outdated, but here's my understanding of how a GFCI works or at least they did some years back  IE AT LEAST BACK THEN THEY DID NOT MEASURE BETWEEN NEUTRAL AND GROUND. They had the Hot and Neutral pass through a torroid coil which detected if BOTH were equal currents and if not (0.006 difference) a voltage was induced in the coil and they tripped. They DID NOT measure between Neutral and Ground like you spoke of, at least back then that is.

Dune, just FYI, a GFCI sensing device does not measure current in the safety bare/green Equipment Grounding Conductor in order to trigger a trip or not. There are ONLY two wires (Hot and Neutral) that pass through a torroid coil. If the current flowing out the Hot is the same as that being returned by the Neutral no voltage is induced into the coil, BUT if the current flowing out is more then that being returned by the Neutral (because its returning elsewhere) a slight voltage is induced which trips the GFCI.

HOWEVER  their design may well have changed since I practiced and its now as you describe????

Please enlighten me of how they work now as I'm never too old to learn

Thanks Vermilye and happy travels to you

John T to longggggggggg retired EE and told you I was rusty lol

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3 hours ago, vermilye said:

Modern GFCIs test for leakage between the neutral & ground.  Shutting off the circuit's breaker will not prevent this type of fault, so it could still be a problem with the fridge heating element.  If you can unplug it, that will be a good test.

If shutting off the branch circuit breakers doesn't identify a bad circuit, digging into the breaker panel and opening the neutrals one at a time is about the only way to check for neutral/ground faults. Might be more than a non electrician would want to get into...

The exact wording in the first sentence here may be a little "technically" incomplete  but the rest of this advice is consistent with my understanding.   Often times to isolate a fault it is necessary to open both the hot and nuetral on each circuit until the fault is found.  A nuetral or hot leakage to a ground on any circuit will trip a GFCI.  Even if that individual circuit is not powered but the nuetral is connected. Electrical heating elements is where I have found many ground faults. Especially in RV electric hot water heaters.  As John T stated a very small circuit fault is all that is needed to trip a GFCI.

Randy

2001 Volvo VNL 42 Cummins ISX Autoshift

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