GFI Outlets Blowing

spmccormick85 · 04-07-2019, 01:28 PM

Hey all, finished my conversion recently. Never had any issues with my shore power or the electrical in the bus until the other day.

If I plug my bus into a shore power circuit with a GFI anywhere in the circuit, the shore GFI automatically trips, instantly. I have nothing being powered in the bus to provide that kind of electrical overload to trip the shore GFI. My shore power/AC line only provides power to outlets in my bus and I have nothing plugged into them. To clarify, the breakers in my bus do not trip, the shore power GFI outlet does. To note, I do have a GFI in my bus.

If I plug into a different circuit with no GFI's in the line, no problems at all. Is this a sign I wired something incorrectly?

Also - I bought a little heater that says not to use an extension cord. I imagine it's because people use to small of a gauge of wire and for the distance run, it's a fire hazard. If I provide the correctly sized wire for the current being drawn at that specific distance, is it still a hazard?

Thanks

TJones · 04-07-2019, 03:09 PM

Is your neutral bonded to ground in you box on the bus. The GFCI is finding something that is grounded that shouldn't be.

Ted

roach711 · 04-07-2019, 03:27 PM

Breakers are there to protect wiring from overloads. GFCI's are there to protect people and to do that they monitor the hot and neutral for an imbalance. They will trip when reading an imbalance of a few mil-amps. Moisture at your plugs can cause GFCIs to trip and I've heard of many bad GFCI outlets causing problems.

"Twas me, I'd switch off all my bus AC breakers then try plugging into a GFCI protected outlet. If the shore panel outlet doesn't trip, switch on each breaker until one trips the outlet GFCI. Once you know which circuit is involved it's a matter of checking your connections and appliances on that circuit.

PNW_Steve · 04-07-2019, 03:53 PM

Quote:

Originally Posted by TJones

Is your neutral bonded to ground in you box on the bus. The GFCI is finding something that is grounded that shouldn't be.

Ted

Good advice above!

I have purchased a number of load centers that came out of the box with the bonding jumper installed.

I suspect that could be your problem.

spmccormick85 · 04-07-2019, 04:02 PM

I must admit I was confused when I bought the breaker panel.

Seems to me the connections for neutral and the ground connect to two different bars in the box, however, the bars are connected by metal machine screws. I would assume this is the issue, contact between the neutral and ground?

Did I purchase the wrong type of box or could it be meant for something else?

I couldn’t get a picture uploaded to this thread but got it loaded as the first pic in my album.

ol trunt · 04-07-2019, 08:55 PM

Hire a licensed electrician to check out your install. Accidentally mixing neutral and ground in your bus can lead to what is called "hot skin" where the bus is waiting for you to step out, touch the ground and complete the circuit. This gets even more complicated when you add a genny to the works so ask about that too. On the bright side, it isn't usual to supply a secondary circuit (like in your bus) from GFI circuit.

For five bucks get one of these at Harbor Freight: https://www.harborfreight.com/electr...sis-63929.html

I check every pedestal at every campground before hooking up. Always.
Jack

TJones · 04-07-2019, 09:01 PM

Quote:

Originally Posted by spmccormick85

I must admit I was confused when I bought the breaker panel.

Seems to me the connections for neutral and the ground connect to two different bars in the box, however, the bars are connected by metal machine screws. I would assume this is the issue, contact between the neutral and ground?

Did I purchase the wrong type of box or could it be meant for something else?

I couldn’t get a picture uploaded to this thread but got it loaded as the first pic in my album.

If your neutral and ground bars are both screwed to the box with metal screws with no insulation between the neutral bar and the box then it is bonded to ground. This will trip a GFCI when plugged in. If this is the case you may be able to find some insulating brackets for your neutral bar.

Not only will this trip a GFCI it could possibly electrify the frame and body of your bus if the box is grounded to the frame and plugged into a non GFCI. I believe the neutral should only be bonded to ground if an onboard power sources such as a battery bank with inverter or generator is used.

Ted

TJones · 04-07-2019, 09:09 PM

Quote:

Originally Posted by ol trunt

Hire a licensed electrician to check out your install. Accidentally mixing neutral and ground in your bus can lead to what is called "hot skin" where the bus is waiting for you to step out, touch the ground and complete the circuit. This gets even more complicated when you add a genny to the works so ask about that too. On the bright side, it isn't usual to supply a secondary circuit (like in your bus) from GFI circuit.

For five bucks get one of these at Harbor Freight: https://www.harborfreight.com/electr...sis-63929.html

I check every pedestal at every campground before hooking up. Always.
Jack

If your not real familiar with AC wiring hiring an electrician is a good idea.

You dont want you or a loved one to get electrocuted or have a fire start.

Also +1 on the tester and checking before you plug in.

Ted

spmccormick85 · 04-10-2019, 02:10 PM

Had to disconnect the ground in the panel on the bus. Makes sense as I’m not sure it would do anything as a shore power line or hookup from inverter. Stopped blowing the GFI though.

TJones · 04-11-2019, 11:08 AM

Quote:

Originally Posted by spmccormick85

Had to disconnect the ground in the panel on the bus. Makes sense as I’m not sure it would do anything as a shore power line or hookup from inverter. Stopped blowing the GFI though.

That's not a good idea. You want your panel and bus connected to ground to ensure any short would go to ground and trip a GFCI or breaker. If ground is not connected your entire bus could be electrified. You just need to make sure neutral is not connected to ground inside the bus. The GFCI detects any connection between hot or neutral and ground. You may also have problem in your wiring somewhere else. It would be best for you to have an electrician review your installation.

Ted

PNW_Steve · 04-11-2019, 12:22 PM

When you are connected to shore power the ground should be bonded to neutral in the shore power pedistal not anywhere on the bus

If you are disconnected from shore power and running on generator then ground and neutral should be bonded at the generator,

ol trunt · 04-11-2019, 02:10 PM

Exactly! Any other way is just asking for a shock.
Jack

spmccormick85 · 04-19-2019, 06:21 PM

So the issue is that for some reason this breaker panel in my bus bonds the neutral and the ground? When I disconnected the ground, nothing blew. Should I buy another ground bar for the panel and ground it to that? Also, what good do these ground bars even do in the bus if they aren’t connected to the chassis?

Also, how can the skin become hot if there’s no AC line touching any metal in the bus? It goes from shore, plugs into breaker, and then the AC lines. None of those lines are touching the bus.

It’s my understanding the only AC current that’s grounded to the chassis is at the inverter which I don’t have installed.

ol trunt · 04-19-2019, 08:24 PM

OK, I'll bite. With all due respect you need to hire a qualified electrician to sort out your wiring. Your questions show that you do not as yet have a complete understanding of electrical systems and a qualified electrician can explain to you while you watch. Sorry if I sound like a jerk but I would really not like to see you get hurt.
Jack

Tango · 04-19-2019, 08:42 PM

I'm with Jack on this and will take it a step further. Hire a qualified "RV electrician".

120v systems any regular sparky can handle. And some are great with 12 volt. The integrated systems on RV's can get tricky. My buddy who has his own commercial electrical company acknowledged he knew zilch as RV's go but did say it looked real easy to create a system that could kill you.

My 2 centavos.

spmccormick85 · 04-20-2019, 08:58 AM

Thanks for the feedback, everyone. I realize this is
a sensitive subject as no one wants to see anybody get hurt.

However, I had an electrician look at it weeks ago, after I originally posted, and he said to disconnect the ground from my panel. So now I’m trying to make sense of what internet folks are telling me versus the electrician.

I reckon I’ll check out the RV electrician, Tango. Thanks!

Sleddgracer · 04-20-2019, 09:17 AM

Quote:

Originally Posted by spmccormick85

Thanks for the feedback, everyone. I realize this is
a sensitive subject as no one wants to see anybody get hurt.

However, I had an electrician look at it weeks ago, after I originally posted, and he said to disconnect the ground from my panel. So now I’m trying to make sense of what internet folks are telling me versus the electrician.

I reckon I’ll check out the RV electrician, Tango. Thanks!

disconnecting the ground will prevent the bus from being hot, but doesn't fix the wiring problem - there are some wires crossed up somewhere

BlackJohn · 04-20-2019, 09:42 AM

To thee Op, can you post a pic of the panel interior , the neutral and ground bars? There might be a bonding screw there that needs removed.
One other thought, how humid is it inside your bus? Damp air will give GFI's reason to trip also and make you believe it is incorrect wiring.
Do be careful till you get this solved. Diagnosing on the internet is not always easy or accurate without pics. We can only assume things are done right, not really knowing what is reality.

John

PNW_Steve · 04-20-2019, 09:48 AM

I strongly suspect that you have ground and neutral bonded in the breaker panel.

Get us a good picture that shows the ground and neutral bus bars we have a better chance of helping you out.

Or......... Call a qualified RV electrician.....

As I think about it something occurred to me. If you had a residential electrician look at it, he may have overlooked the issue. In a typical household installation you DO bond ground and neutral at the panel.

The panel in an RV is treated as a sub-panel.

spmccormick85 · 04-20-2019, 09:55 AM

Everyone seems to be fixated on the bus potentially becoming “hot.” I apologize because I must not have explained the system very well.

There is no inverter hooked up. The AC outlets work Only from shore power. It’s basically like having an extension cord run through the bus with outlets here and there.

The panel is not grounded to the bus. The ground I disconnected is just from a ground bar in the panel (which I suspect contacts the neutral causing the short.) The panel itself is attached to a piece of plywood.

At no point, anywhere in the bus, does a line of circuitry connect to the metal frame or skin of the bus. Everything is safely protected by conduit and placed in junction boxes. There is no way to have a hot skin with this current setup.

I still go back to the type of panel I have, was anyone able to make sense of that picture? Rules of deduction tell me I should be able to just buy another ground bar, place in the panel separate from the neutral, and test my connections?

I’m on the road but this will help me make sense of it when I get somewhere to work on her. 4000 miles down! Thanks!

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