Confused why my electric hookup shorts out...

[brownkenvt]

I have a home-built teardrop camper with a 30 amp power plug and an inverter so I can use DC when there are no hookups available or can hookup when there are. My car also charges the teardrop camper battery when I'm driving, so it works out pretty well. When I'm home I plug my camper into my house current, using an adaper on the 30 amp power cord to give me a male plug with a standard two prong household plug. That works fine too.
The problem is last week I was at a campground with a post with two 20 amp breakers with standard household type female outlets. When I used the same power cord setup I use at home it would trip the breaker each time.  I assumed I had some kind of a short in my camper. However, when I returned home I plugged in to my wall plug and it worked just fine. Was it a campground problem ? Or am I missing something?

 

[Alfa38User]

....and an inverter so I can use DC when there are no hookups available....

As an FYI, I think you mean a CONverter (120V to 12V DC)
An inverter uses 12V DC (Battery) to produce 120C AC.

If they had 2 20 amp breakers and you normally use only one at home, it could be they were never meant to use both in your set-up. It could also be that theirs had the connections reversed compared to yours. I am pretty sure that would blow the breaker right away.

Are yours wired the correct way? Brass to black wire and white to other silver terminal (neutral). Not saying yours is wrong but that it was simply different compared to what yours expected.

 

[John From Detroit]

Ok, how old is your house? (Don't answer) By Code all Newer than a specific date 15/20 amp outlets MUST be GFCI protected. odds are the park outlets were so protected.  Some use GFCI outlets. but I've been to a few that use GFCI circuit breakers (Look for a TEST button, GFCI breakers have them).

If your house is old enough or if you installed that outside outlet yourself it might NOT be GFCI.

NOT all RV's play nice with GFCI.. I will leave others to explain if that's the case.

 

[mel s]

I have a home-built teardrop camper with a 30 amp power plug and an inverter so I can use DC when there are no hookups available or can hookup when there are. My car also charges the teardrop camper battery when I'm driving, so it works out pretty well. When I'm home I plug my camper into my house current, using an adaper on the 30 amp power cord to give me a male plug with a standard two prong household plug. That works fine too.
The problem is last week I was at a campground with a post with two 20 amp breakers with standard household type female outlets. When I used the same power cord setup I use at home it would trip the breaker each time.  I assumed I had some kind of a short in my camper. However, when I returned home I plugged in to my wall plug and it worked just fine. Was it a campground problem ? Or am I missing something?

brownkenvt
I suspect the 20A campground outlets where GCFI protected and that your teardrop camper has a ground fault that tripped the GFCI.
See: http://www.everything-about-rving.com/why-does-my-rv-keep-tripping-gfci-electrical-outlets.html
And: https://www.controleng.com/single-article/understanding-ground-fault-protection/1ac7a42476e6f5e860be06426846d180.html

 

[Daffy]

I'll add one, did ya disconnect the car? since you said the car charges the camper battery....

 

[grashley]

I also suspect GFCI issues.  I had my camper plugged into 20A GFCI for a couple weeks, and it tripped every night, probably due to dew on the exposed plug.

GFCI knows EXACTLY how many electrons pass through on the hot wire.  If that same number of electrons do not return on the neutral wire, it knows they found a different route to ground - ground fault - and trips the circuit.

30A circuits do not have GFCI.  As John said, current code requires GFCI for any outside 15 or 20A outlet, including RV parks.

Does your RV electrical panel keep white (neutral) and bare (ground) wires separate?  If not, there could be the problem.  I know they tie together in the house wiring, but that is on the other side of the GFCI.

 

[Optimistic Paranoid]

Does your RV electrical panel keep white (neutral) and bare (ground) wires separate?  If not, there could be the problem.  I know they tie together in the house wiring, but that is on the other side of the GFCI.

I don't believe any commercial RV would tie the two together.  Certainly not one built to the even oh-so-loose RVIA code.  The National Electrical Code requires all sub-panels to keep them separate, and as far as RVs are concerned, their panels are sub-panels to the campground's master panel.

 

[darsben]

I don't believe any commercial RV would tie the two together.  Certainly not one built to the even oh-so-loose RVIA code.  The National Electrical Code requires all sub-panels to keep them separate, and as far as RVs are concerned, their panels are sub-panels to the campground's master panel.

Except OP stated his is home built

 

[Lou Schneider]

Like others have said, the first place I'd check is the teardrop's circuit breaker panel, especially if you used one intended for a house.  The ground and neutral wires should each be on their own busses, with the neutral buss on insulated standoffs to keep it electrically isolated from the metal case and the ground buss.

If you have an ohmmeter, use it to verify there's no continuity between the neutral and ground busses.

Sometimes there is a bonding screw that connects the two busses together for applications that require that.  If your panel has the bonding screw installed, remove it.

 

[brownkenvt]

As an FYI, I think you mean a CONverter (120V to 12V DC)
An inverter uses 12V DC (Battery) to produce 120C AC.

Actually no. It's an inverter. We run off of DC until we plug in, or turn on the inverter if we need AC to run the Coffee Grinder or the Computer.

 

[brownkenvt]

If they had 2 20 amp breakers and you normally use only one at home, it could be they were never meant to use both in your set-up. It could also be that theirs had the connections reversed compared to yours. I am pretty sure that would blow the breaker right away.

Are yours wired the correct way? Brass to black wire and white to other silver terminal (neutral). Not saying yours is wrong but that it was simply different compared to what yours expected.

They had two separate 20 amp breakers and outlets... to use seperately. Both had the same result. Tripped the breaker.
Pretty sure I'm wire the correct way... brass to black etc. worth checking.

thanks

 

[brownkenvt]

Ok, how old is your house? (Don't answer) By Code all Newer than a specific date 15/20 amp outlets MUST be GFCI protected. odds are the park outlets were so protected.  Some use GFCI outlets. but I've been to a few that use GFCI circuit breakers (Look for a TEST button, GFCI breakers have them).

If your house is old enough or if you installed that outside outlet yourself it might NOT be GFCI.

NOT all RV's play nice with GFCI.. I will leave others to explain if that's the case.

Hmmm. My 2 prong ac outlets in the kitchen area of my camper are GFCI  and have breakers... the interior AC outlets do not. And the 3 prong 30 amp plug on the exterior of the camper (underneath that nice expensive chrome screw cap) does not have a breaker. Are you saying the newer exterior camper's female hookup plugs have a GFCI breaker there?

 

[brownkenvt]

I'll add one, did ya disconnect the car? since you said the car charges the camper battery....

 

[brownkenvt]

I'll add one, did ya disconnect the car? since you said the car charges the camper battery....

Hey Daffy... That's not it... But that one has caught me before 8)

 

[John From Detroit]

The 30 amp plug under the nice chrome cap SHOULD feed the main breaker on your breaker panel.

Suggestion. Turn off all breakers.. Plug a Trouble light (Drop cord) into the same 20 amp outlet that trips when you plug in the RV (or rather the other half of the duplex. not the other outlet but the other half of the same outlet).

now Does the light work.. Good.  if breaker trips you likely bonded neutral to ground in the breaker box but look for an N-G Short as described above

If light stays on.
Put it where you can see it when operating breakers.
Turn on the main breaker.. Light stays on good. light goes off bad..
Turn on first branch. Light on - Good. light off Take a note of what that breaker feeds. Turn off and reset
Then do that with the next, and the next, till every breaker is either on. or noted.

Post the results.

 

[grashley]

Certainly your camper is wired this way and I misread your post, but the 30A feed should go directly to a breaker box, feeding a 30A main breaker, then from here, power goes to the other breakers which feed the camper.  I am still concerned the white - neutral and bare or green - ground wires are not separated in this box.  In a house, it does not matter.  In a camper, they MUST be isolated or they will trip any GFCI feeding the camper.

 

[brownkenvt]

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.

I arrive at a campground with two outlets on a post. Each is protected by a 20 amp circuit breaker. I plug in the same 30 amp cable and two prong adapter. The LED light shows power to the end of the cable where it plugs into the camper. The minute the cable touches the camper, the 20 amp circuit breaker shuts off on the post.  ( I also tried plugging in with the breaker off, then turning the breaker on -- same result.)

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

 

[NY_Dutch]

How many circuit breakers are in your teardrop panel, Ken?

 

[brownkenvt]

How many circuit breakers are in your teardrop panel, Ken?

There are four. But I think that is immaterial. Mycircuit breakers are not tripping.  It is the 20 amp circuit breaker on the campground post that is tripping.

 

[Alfa38User]

What happened if you turned all the CB off in the RV first then plug into the trailer then the post  (including the 30 amp breaker on the trailer)?  (Probably too late for that though!!) But to finish the test, if the post CB did not trip, then you could turn on each one, one at a time, and perhaps identify the circuit causing the problem if there is one in the trailer. If the result blows the post breaker right off, then you have a cord problem.

But I think that is immaterial. My circuit breakers are not tripping.

Not necessarily. The post breakers may have been weak and tripped more quickly/easily that the ones in your trailer.