Confused why my electric hookup shorts out...

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brownkenvt said:
Sorry I'm not more of an electrician -- that was the hardest part of my build. (Then I'll have to go to a campground to test whether I've solved it or not before  our next big trip!?!)
Here is your whole problem, you are not an electrician. You really need to hire a real electrician to come out and find out what is going on.
 
It seems the consensus is that I need to go thru my camper and find where I have wired i hot to ground (and ground to hot) on some outlet or fixture. Is that right?
I'll try to explain, but you will need to learn more about electrical wiring than you do now.

Odds are that the breaker trip is a ground fault rather than a short, but with the info you have provided it could be either.
A ground fault occurs when current (amps) return via the ground wire instead of the neutral.  That happens in one of two ways: (1) a "hot" touches a ground wire or some surface (the vehicle frame in this case) that itself id wired to the ground, or (2) a neutral wire is touching the ground wire or a grounded surface. Either of those lets current flow in the ground wire and a GFCI breaker will detect that and trip.

The #1 I described is also a direct short, so that would trip a breaker whether it is a GFCI type or not. Since your rig doesn't trip a breaker at home, I'm thinking this is NOT what is happening. Therefore #2 is the most likely situation.

Is the circuit you plug to at home protected by a GFCI outlet or breaker?  My guess is that it is not. If so, the campground problem is very likely to be GFCI related.

If you installed a standard electrical panel (load center) in the trailer, it probably came with the neutral and ground buses bonded toegther (electrically connected). That is NOT proper for an RV, which must follow the rules for electrical sub-panels and therefore not have neutral & ground buses tied together ("bonded", in electro-speak).
 
brownkenvt said:
Thanks grashley and detroit and others for your suggestions.

Let me describe again, as clearly as I can, what was happening, so that I can be sure we on the same page.

I can plug in my home built teardrop, with DC wiring and an inverter, into my house currant with a 30 amp plug cable with an adapter to a two prong standard plug to my house outlet. The cable has a LED blue light that shows me the cable has power. House powers my camper and charges the battery -- no problem.

It seems the consensus is that I need to go thru my camper and find where I have wired i hot to ground (and ground to hot) on some outlet or fixture. Is that right? Sorry I'm not more of an electrician -- that was the hardest part of my build. (Then I'll have to go to a campground to test whether I've solved it or not before  our next big trip!?!)

Ken

Ken
If you simply replace the standard house outlet with a GFCI outlet you can do the testing at home:
http://www.buildmyowncabin.com/electrical/wiring-gfci-outlet.gif
 
brownkenvt said:
Thanks for that GREAT suggestion.

NOW, maybe that can eliminate some things. The electrical system in my camper works fine plugged into the GFCI outlet in my bathroom -- with and without the breakers in my camper on. NO PROBLEMS. That helps me think back to the campground in St. Paul (Lake Elmo) to those outlets (which did not in my memory) look like GFCI outlets and had regular 20 amp circuit breakers alongside them that were the ones that were tripping.

So maybe now I can assume it was a campground problem?? Ya think?

Ken

I DO!
 
First, I apologize for accidentally deleting Brownkevint's post that was quoted in the message above this one.  Fat fingered mistake on my part.  :(

Now, then ...

Was your tongue jack sitting on the ground at home, or was it on pavement?  This would isolate the trailer frame from ground and keep the bathroom GFCI from tripping, even though the trailer frame was electrified.  I assume the tongue or the stabilizer jacks were on the ground at the campground?

The problem is you have neutral and ground connected together in your teardrop. Since you're using a two wire cheater plug and the GFCI tripped at the campground, this confirms the ground in the box has a path to the trailer frame, then to earth.

This rules out a hot to frame short, which would give you a shock any time you touched the ground and the teardrop at the same time.

Of course, plugging in the two wire plug upside down, or plugging into a miswired outlet, will swap the hot and neutral lines, creating a hot to frame short.  So it behooves you to find and eliminate the problem.

Like I said above, start by looking at your breaker box. Are the ground and neutral wires each on their own buss, or they sharing a common buss?  Is the neutral buss insulated from the box via standoffs?  If this is correct so far, is there a bonding screw connecting the neutral and ground busses together?

If you're sure neutral and ground are kept separate inside the box, and neutral is isolated from the box frame, then work outwards from there.
 
Lou Schneider said:
First, I apologize for accidentally deleting Brownkevint's post that was quoted in the message above this one.  Fat fingered mistake on my part.  :(

Now, then ...

Was your tongue jack sitting on the ground at home, or was it on pavement?  This would isolate the trailer frame from ground and keep the bathroom GFCI from tripping, even though the trailer frame was electrified.  I assume the tongue or the stabilizer jacks were on the ground at the campground?

The problem is you have neutral and ground connected together in your teardrop. Since you're using a two wire cheater plug and the GFCI tripped at the campground, this confirms the ground in the box has a path to the trailer frame, then to earth.

This rules out a hot to frame short, which would give you a shock any time you touched the ground and the teardrop at the same time.

Of course, plugging in the two wire plug upside down, or plugging into a miswired outlet, will swap the hot and neutral lines, creating a hot to frame short.  So it behooves you to find and eliminate the problem.

Like I said above, start by looking at your breaker box. Are the ground and neutral wires each on their own buss, or they sharing a common buss?  Is the neutral buss insulated from the box via standoffs?  If this is correct so far, is there a bonding screw connecting the neutral and ground busses together?

If you're sure neutral and ground are kept separate inside the box, and neutral is isolated from the box frame, then work outwards from there.

Actually, at the campground I did not have stabilizer or tongue touching ground -- only rubber wheels and rubber wheel on crank on the tongue.

Today, the camper is on pavement in my garage, but I just grounded the tongue with a metal pipe to the ground outside to no effect.  I can take a look inside the breaker box... but we've been using this camper (and this breaker box) sucessufully in years past at other hookups and not had issues, so I think I recall removing the bonding screw when I built this thing years back.

Oh... and my cheater converter from 30 amp to is 3 wire... it includes a ground prong.

 
After all this discussion, I am beginning to agree that it was that particular campground that was the problem and you are chasing ghosts around your equipment!!
 
brownkenvt said:
Actually, at the campground I did not have stabilizer or tongue touching ground -- only rubber wheels and rubber wheel on crank on the tongue.

Today, the camper is on pavement in my garage, but I just grounded the tongue with a metal pipe to the ground outside to no effect.  I can take a look inside the breaker box... but we've been using this camper (and this breaker box) sucessufully in years past at other hookups and not had issues, so I think I recall removing the bonding screw when I built this thing years back.

Oh... and my cheater converter from 30 amp to is 3 wire... it includes a ground prong.

brownkenvt:
What exactly is the "cheater converter from 30 amp" you're using?
Can you post a photo, or the p/n, of your "cheater converter"?

Methinks you should be using a 30A female to 15A male electric adapter like this:
https://cdn3.volusion.com/wckp9.3xkgs/v/vspfiles/photos/VTS-420-2.jpg?1466418338
OR this:
https://tinyurl.com/y7ba5eqa

(Many "cheater converters" will not/can not work in a GFCI protected outlet/receptacle) 
 
brownkenvt said:
  I can take a look inside the breaker box... but we've been using this camper (and this breaker box) sucessufully in years past at other hookups and not had issues, so I think I recall removing the bonding screw when I built this thing years back.

Oh... and my cheater converter from 30 amp to is 3 wire... it includes a ground prong.
With this new information - it works at home plugged into GFCI  and it has worked at other campgrounds (I assume using 20A plugs) certainly points to the camper is fine.  The campground has a problem.
 
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