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Old 10-21-2016, 12:28 PM   #1
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30a to 15a stepdown adapter trips house GFI outlet

A couple of weeks ago I had to spend a night at Camping World while they resolved an issue with our coach. They were nice enough to provide a 15 amp outlet so I could have basic power that night. This was the first time I had to use my step down 30a-15a dogbone adapter. When hooking it up to the outlet it tripped the GFI there. We tried everything - made sure nothing was running in the coach (a/c, etc), even going as far as enabling the battery disconnect switch. The techs at CW said it must be a bad GFI outlet and apologized. We ended up using the generator.

Well the other day I wanted to plug in at home before leaving on a trip. I attempting to plug into an outlet in our garage (also GFI) and it did the same exact thing.

So I made a call to Thor and the tech there told me that I should plug into a non GFI outlet since GFI outlets have the polarity reversed and that is what is causing it to trip.

Once I ran the extension cord inside and plugged into a non GFI 15a outlet everything worked fine.

What's concerning to me is how CW was totally oblivious to this and thought it was their GFI outlet that was to blame.

My question is what do others do to connect their coaches to 15a outlets at home when most garage and outdoor plugs are GFI? Is there a special adapter I need to plug into my stepdown 30a-15a dogbone adapter?
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Old 10-21-2016, 12:33 PM   #2
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Interesting: I've always plugged all of our campers into the GFI protected outlet in our garage (this includes two TT's, one 5th wheel, and now our Axis).

The only issue I've had is the obvious one: Attempting to run the A/C will trip the breaker in some instances (If I ensure that all devices on that circuit are off I can run the A/C but as soon as something else is added...poof! off it goes LOL). (The downside is that the garage outlets in our house are protected by the same GFI as in the bathrooms which means as soon as someone turns on a hair dryer the breaker trips.) We've never had the GFI trip.
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Old 10-21-2016, 12:51 PM   #3
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I think it may be related to how RVs are grounded.

I have/had (different units) same problem connecting off GFI at front porch which trips even if everything in RV is/was off. By comparison connecting at garage which is not GFI protected has always worked fine.
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Old 10-21-2016, 12:55 PM   #4
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Originally Posted by JamieGeek View Post
....cut.... We've never had the GFI trip.
Do you exercise it regularly to make sure it's working right? I read somewhere it should be done monthly -- not sure though.
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Old 10-21-2016, 01:05 PM   #5
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polarity reversed makes no sense to me at all. I think they were blowing smoke your way.

I plug into one at my house all the time. A couple times I have gotten a GFCI trip at initial plug in for some reason that I have never figured out, but if I reset the outlet things are fine. Most of the time it doesn't trip it.
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Old 10-21-2016, 01:58 PM   #6
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Reverse polarity was their polite way of saying "I don't really know what the problem is but I'm not going to admit that to you because I'm the expert"!!! I have used both GFI and non-GFI plugs on several RVs and have never had a problem. I call BS on that one!
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Old 10-21-2016, 02:35 PM   #7
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Same here. Never a problem with plugging into a GFI. Maybe try a different adapter.
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Old 10-21-2016, 03:26 PM   #8
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Quote:
Originally Posted by Chance
Do you exercise it regularly to make sure it's working right? I read somewhere it should be done monthly -- not sure though.
Good question: Nope, same GFI in the house for years and I haven't touched it LOL.

Keep in mind what GFI does: The GFI trips when there is a short from one of the "hot" legs to ground (e.g. drop the toaster in water). Reversing the polarity (e.g. swapping the two "hot" wires) would not trip the GFI at all.
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Old 10-21-2016, 03:33 PM   #9
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As I understand it, in a house neutral and ground are tied together, as is the case with many RVs. The problem I see is that an RV parked on the driveway is not grounded to the same ground as the house, or actually grounded much at all since it's isolated by the tires.

When you first plug in, I think it's possible any difference in potential between the house and the RV may cause a momentary imbalance between current in hot leg and neutral which trips the GFI. We are only talking about 5 milliamperes or so, which isn't much.

When I get back home I'm going to experiment by first grounding the RV's electrical to the house independently and then plug in. I'm curious if that will prevent tripping.

What may be happening sometimes is "similar" to what happens when we get shocked by touching a car. The difference is that GFI senses the current imbalance on initial plug-in and trips.
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Old 10-21-2016, 03:39 PM   #10
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Originally Posted by JamieGeek View Post
Good question: Nope, same GFI in the house for years and I haven't touched it LOL.

Keep in mind what GFI does: The GFI trips when there is a short from one of the "hot" legs to ground (e.g. drop the toaster in water). Reversing the polarity (e.g. swapping the two "hot" wires) would not trip the GFI at all.
As I understand it, GFI compares current in hot leg to neutral, and if it's not identical (within 5 milliamperes or so) will trip. It does not have to go to ground.

Basically it protects us from shock by making sure we don't become a path from the hot leg to ground. If we do, then the current returning through neutral wouldn't match the hot, which is why it trips. It's a clever way to protect us indirectly.
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Old 10-21-2016, 03:42 PM   #11
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I might add this is a brand new 2017 Thor Freedom Elite 29FE that comes from the factory with a 1000w inverter. I have had zero electrical issues. Again, it is only an issue when attempting to plug into a 15amp GFI which is what I'm dealing with if I want to use an outside or garage plug. I really don't want to continue to run a cord inside my house to plug in. Of course I could replace the GFI in the garage with a standard one but I'd like to figure out what the issue is if I can since I will be stopping at my sister's house and I will run into the same issue there while moochdocking.
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Old 10-21-2016, 04:09 PM   #12
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Here is some educational reading: NEMA GFCI (pdf). Its a power point presentation and look at page 9:
Quote:
Why GFCIs must be installed a certain way
• For Circuit Breaker GFCI:
To prevent constant tripping, MUST connect Load Neutral to circuit breaker neutral
terminal, NOT panelboard neutral.
• For Receptacle GFCI:
If line and load conductors are reversed, per 2010 edition UL 943, no power is
available at:
1.Face terminals or
2.Line terminals connected to downstream receptacles.
Well then, never mind: If line and load are reversed no power is available.
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Old 10-21-2016, 04:22 PM   #13
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Have you tried resetting the GFI while the coach is still plugged in -- like blw2 mentioned in post above, that may work. It's worth a try.

If that doesn't do it, I'd try to find what is leaking by turning everything off and then start by adding one thing at a time. I'd start with extension cord alone first, then add adaptor, etc... Inside RV I'd start with all breakers off and see if that prevents tripping. It's a difficult job for sure.
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Old 10-21-2016, 04:23 PM   #14
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I plug my 2015 Vegas into GFCI in my garage and never had a problem. Have you ever tried using a different dogbone?

Is the inverter on when you try plugging in? Have you tried turning off the inverter?

It did it at CW and it's also doing it at your home. Have you tried plugging it in at a third GFCI somewhere? It worked in a non-GFCI plug at your home.

Jamie -- if what you said based on the PP slide is true, wouldn't that receptacle trip no matter what was plugged in. I'm going to make an assumption that only his RV setup trips the GFCI at his home and the receptacle at CW. If it works when anything else is plugged in, and his RV works when plugged in to non-GFCI, wouldn't that narrow the problem down to either the dogbone or his cable?

I'm taking the dogbone in the "cause pool."
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Old 10-21-2016, 04:29 PM   #15
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Quote:
Originally Posted by Chance View Post
Have you tried resetting the GFI while the coach is still plugged in -- like blw2 mentioned in post above, that may work. It's worth a try.

If that doesn't do it, I'd try to find what is leaking by turning everything off and then start by adding one thing at a time. I'd start with extension cord alone first, then add adaptor, etc... Inside RV I'd start with all breakers off and see if that prevents tripping. It's a difficult job for sure.
Resetting the GFI causes and immediate trip. Resetting again causes another immediate trip.

Everything is turned off including the battery disconnect switch.

It doesn't trip until i connect the dogbone to the 30amp connector. Connecting the dogbone connector by itself won't cause a trip since no load.
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Old 10-21-2016, 04:31 PM   #16
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Originally Posted by bevedfelker View Post
I plug my 2015 Vegas into GFCI in my garage and never had a problem. Have you ever tried using a different dogbone?

Is the inverter on when you try plugging in? Have you tried turning off the inverter?

It did it at CW and it's also doing it at your home. Have you tried plugging it in at a third GFCI somewhere? It worked in a non-GFCI plug at your home.

I'm taking the dogbone in the "cause pool." Inverter would be my alternate choice.
Inverter is OFF.

I will try another dogbone adapter and report back. It's a brand new Camco dogbone adapter that I bought less than a month ago and never used.

I'd doubt that two different defective GFI's are the cause. I can try a third at some point.
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Old 10-21-2016, 05:40 PM   #17
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Turn off all the breakers inside the coach before plugging into the GFCI outlet. If the GFCI trips start looking for an issue around the converter.

If the GFCI does not trip, start turning on the breakers one at a time, waiting a minute or two between each, until you find the one that trips the GFCI.

Also, I have read other forums where there were issues in which the RV electrical system was grounded, due to generators and automatic transfer switches, causing GFCI outlets in garages to trip. Read a couple that also stated the lenght of wiring from the house breaker panel to the GFCI and then the length of the cord going to the RV can cause a false tripping of the GFCI.
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Old 10-21-2016, 05:44 PM   #18
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Originally Posted by dstankov View Post
Turn off all the breakers inside the coach before plugging into the GFCI outlet. If the GFCI trips start looking for an issue around the converter.

If the GFCI does not trip, start turning on the breakers one at a time, waiting a minute or two between each, until you find the one that trips the GFCI.

Also, I have read other forums where there were issues in which the RV electrical system was grounded, due to generators and automatic transfer switches, causing GFCI outlets in garages to trip. Read a couple that also stated the lenght of wiring from the house breaker panel to the GFCI and then the length of the cord going to the RV can cause a false tripping of the GFCI.
OK, but it trips with the battery disconnect on the STORE position. Wouldn't that mean nothing is running to the coach? Why would turning off each of the breakers beforehand make a difference?
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Old 10-21-2016, 05:52 PM   #19
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Originally Posted by Thordog
OK, but it trips with the battery disconnect on the STORE position. Wouldn't that mean nothing is running to the coach? Why would turning off each of the breakers beforehand make a difference?
Because the use/store switch just disconnects 12V. You want the breakers off to isolate the 120V system.

In theory with all the breakers off the only thing plugged into the wall is the cabling and the 30A->15A adapter. Then you turn one breaker on at a time until the GFI trips.
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Old 10-21-2016, 06:01 PM   #20
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Because the use/store switch just disconnects 12V. You want the breakers off to isolate the 120V system.

In theory with all the breakers off the only thing plugged into the wall is the cabling and the 30A->15A adapter. Then you turn one breaker on at a time until the GFI trips.
OK, I know the fuse panel is located at the foot of the bed. Are there any other breakers I need to turn off besides at that box?
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