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Author Topic: Outlets on GFCI branch circuit not working  (Read 369 times)

Jax3

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Outlets on GFCI branch circuit not working
« on: October 25, 2017, 10:41:16 AM »
Hello all...I have 2010 fifth wheel that when I hook it up to a 50A generator with the power cord, all outlets work, including the GFCI.

When I go to a state park, most of the power is 30A, so I use a 50-30 converter.  When I do this, my GFCI in the bathroom trips, which results in losing my exterior outlet and most of my galley plugs that are on that circuit.

I don't have an adapter to use with the genny to verify if it is a pedestal issue problem that trips the GFCI, if it is the adapter causing the problem, or if something else.

Anyone have any ideas?

Thanks!
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Old Blevins

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Re: Outlets on GFCI branch circuit not working
« Reply #1 on: October 25, 2017, 11:02:38 AM »
Do you ever plug in to a 20A socket with an adapter and, if so, does the GFCI trip then?
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glen54737

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Re: Outlets on GFCI branch circuit not working
« Reply #2 on: October 25, 2017, 12:57:46 PM »
It sounds like a ground fault in the wiring of the circuit downstream of the GFCI. the ground connection is different when using a portable generator versus shore power.
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Gary RV_Wizard

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Re: Outlets on GFCI branch circuit not working
« Reply #3 on: October 25, 2017, 04:36:42 PM »
It's not the pedestal.  You have a ground fault in the RV, a short that goes from hot or neutral to the ground wire in the RV. When using your portable genset, the coach ground wire doesn't connect to anything because ground isn't bonded to neutral in those gensets. When on shore power, however, the RV ground connects to the campsites wiring which definitely has a solid ground connection (bonded at the campground main power panel).    The net result of that is that your short circuit isn't really shorted when on the genset, but it is on shore power.  However, if you happened to touch the wrong thing in the RV when using the genset, you could still get a shock (or worse). The lack of a genset ground merely makes that particular kind of short undetectable to the GFCI.
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John From Detroit

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Re: Outlets on GFCI branch circuit not working
« Reply #4 on: October 25, 2017, 05:56:07 PM »
I agree with the Ground fault... THe reason the Generator allows the GFCI to work is that there is no ground on the genny.. No ground = No ground fault.
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Arch Hoagland

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Re: Outlets on GFCI branch circuit not working
« Reply #5 on: October 25, 2017, 06:07:39 PM »
Can you reset the GFI after it kicks?


If I plug into my 15 amp house outlet it will trip the GFI inside my coach. Solution is...I turn off the two 50 amp breakers inside the coach, then plug into my house and turn the 50 amp breakers back on and everything works OK.

Only thing I can think of is the the ground prong is longer on the extension cord and perhaps that is causing the problem.

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Jax3

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Re: Outlets on GFCI branch circuit not working
« Reply #6 on: October 26, 2017, 09:54:05 AM »
Thanks for the information.  To start, if I use a 20A plug with an adapter, I only have one leg of the 220, so only half the circuits work.

The GFCI in the 5th trips immediately if I reset it.

So...if I wanted to correct the problem, what do you think it might be?  I've pulled each of the plugs, checked for any continuity and shorting, found none.  I also replaced the GFCI.  It makes since that something is going on somewhere...another idea...I planned on going to a 50A pedestal in the same campground to see what happens to help isolate the problem.  If it doesn't trip when on 50A shore, then I would think it has something to do with the adapter, correct?
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Gary RV_Wizard

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Re: Outlets on GFCI branch circuit not working
« Reply #7 on: October 26, 2017, 10:22:18 AM »
Quote
To start, if I use a 20A plug with an adapter, I only have one leg of the 220, so only half the circuits work.
That would be a faulty adapter. A standard 50/30 adapter powers both legs of a 50A shore cord and everything works, even though the total power available is still only 30A (or whatever the shore source provides).   Adding a 30/15 or 30/20 adapter to the 50/30 doesn't change that.

Changing pedestals won't alter anything. Any outlet that has a functioning ground is going to produce the same result.

What is on the branch circuit that trips? That's where you start looking. Some common causes are a damp or dirty outdoor outlet, the converter/charger or the fridge electric heat element (but only if on that circuit).
« Last Edit: October 26, 2017, 10:26:20 AM by Gary RV_Wizard »
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Jax3

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Re: Outlets on GFCI branch circuit not working
« Reply #8 on: October 26, 2017, 10:28:48 AM »
That would be a faulty adapter. A standard 50/30 adapter powers both legs of a 50A shore cord and everything works, even though the total power available is still only 30A (or whatever the shore source provides).   Adding a 30/15 or 30/20 adapter to the 50/30 doesn't change that.

Okay...I don't think I thought of that.  So...when I tried that...I used my 50A cable to the 50/30ATT adapter; I then used the 30A to 110 adapter, and was only powered on one side.  My thinking that this was accurate, as there is only one hot leg on the 110.  I didn't think it through the other way, which is that the legs were already jumpered at the 50/30 adapter, and only one leg there also.  Am I understanding it correctly?

In regards to what trips...it is only the circuit with GFCI outlet, which is the bath sink (GFCI there, has been replaced), three outlets in the galley (when I opened each one I saw no issues), and the exterior receptacle, which has also been replaced.
« Last Edit: October 26, 2017, 11:08:41 AM by Jax3 »
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Gary RV_Wizard

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Re: Outlets on GFCI branch circuit not working
« Reply #9 on: October 26, 2017, 04:05:21 PM »
Quote
I didn't think it through the other way, which is that the legs were already jumpered at the 50/30 adapter, and only one leg there also.  Am I understanding it correctly?

Yes. If the 50/30 works, adding the 15/20 doesn't change anything.

One of those things on that circuit has a short to ground, either direct to the ground wire or to the RV frame, which is also connected to the shore power ground wire.  The GFCI trips when it detects an imbalance between the hot and neutral as it passes through, meaning some of the amps are going somewhere else. It doesn't take much - just 6 milli-amps. A single strand of wire brushing a nearby surface would do it, even though the outlet or device still works properly.
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grashley

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Re: Outlets on GFCI branch circuit not working
« Reply #10 on: October 26, 2017, 06:25:19 PM »
Try this??

Disconnect the LOAD side from the GFCI. (power in only)  Will it stay set and work?

Reconnect the next receptacle ONLY, disconnecting the down stream side.  Will the GFCI stay set and work?

Add the next receptacle .......

This may help isolate the location of the problem, at least.
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meternerd

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Re: Outlets on GFCI branch circuit not working
« Reply #11 on: October 27, 2017, 09:05:36 PM »
A GFCI compares the "hot" current to the "neutral" current.  Any difference and the GFCI "assumes" that the difference is a fault going to ground.  With a shared neutral, such as what most adapters supply, the GFCI may not be wired to the neutral directly, so it senses a difference.  It all depends on how the trailer was wired.  The solution is not simple, and requires a rewire of the AC supply to the converter or a different adapter.  More than can be explained here....get a pro to check it out.  The option is not to use an adapter, but to connect to the correct 50A receptacle.  I could explain how to "defeat" the GFCI, but I won't.
« Last Edit: October 27, 2017, 09:10:02 PM by meternerd »

Gary RV_Wizard

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Re: Outlets on GFCI branch circuit not working
« Reply #12 on: October 28, 2017, 09:21:59 AM »
Quote
With a shared neutral, such as what most adapters supply, the GFCI may not be wired to the neutral directly, so it senses a difference.

I realize this is complex to discuss via typed messages, but I'm not clear what you mean by this. A 50A shore cord has a single "shared neutral" in all cases, so adding an adapter doesn't alter that. Further, the GFCI that is tripping is a branch circuit in the RV, so can only sense differences in neutral current that are upstream from it.
Gary
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Jax3

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Re: Outlets on GFCI branch circuit not working
« Reply #13 on: October 30, 2017, 09:42:45 AM »
A GFCI compares the "hot" current to the "neutral" current.  Any difference and the GFCI "assumes" that the difference is a fault going to ground.  With a shared neutral, such as what most adapters supply, the GFCI may not be wired to the neutral directly, so it senses a difference.  It all depends on how the trailer was wired.  The solution is not simple, and requires a rewire of the AC supply to the converter or a different adapter.  More than can be explained here....get a pro to check it out.  The option is not to use an adapter, but to connect to the correct 50A receptacle.  I could explain how to "defeat" the GFCI, but I won't.

Problem is if the campgrounds have very few 50A pedestals, and none are available.  No genset (that and I'm sure they wouldn't like it), so not much of a choice there.  Many other people use adapters there with no issues, so something wrong with my setup.

Thanks for the input about the wiring though...more to think about.
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Jax3

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Re: Outlets on GFCI branch circuit not working
« Reply #14 on: October 30, 2017, 09:44:30 AM »
Try this??

Disconnect the LOAD side from the GFCI. (power in only)  Will it stay set and work?

Reconnect the next receptacle ONLY, disconnecting the down stream side.  Will the GFCI stay set and work?

Add the next receptacle .......

This may help isolate the location of the problem, at least.

Good idea.  That's why I come here, to get ideas on how to fix it.  I'm not as familiar with TT systems, but very much so with house wiring.  My troubleshooting skills are lacking at times, such as this.
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schoolsout2

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Re: Outlets on GFCI branch circuit not working
« Reply #15 on: October 30, 2017, 10:12:39 AM »
Similar problem in our MH.  Cleaned shore cord terminals.  Maybe it will work for you.
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