Need some help, shore power tripping breaker/buzzing

[love4god]

My fifth wheel has been sitting all winter and I just pulled it out to set it up for some friends who are staying over for the weekend.

We cleaned it out, plugged it in, everything was fine. Then all of a sudden the circuit (HOUSE circuit, not RV circuit) tripped. Now when I try to plug it in I hear an audible and frightening buzz and the breaker trips in about a second.

What's really odd is that I turned off ALL the RV breakers and it still does it. SO does that mean something is wrong with the shore plug?

I used a different extension cord, heavy duty and shorter, and a different house circuit and the same thing. So if the breakers are off and just plugging the cord into shore power trips the shore breaker I'm thinking that there must be a short in the shore plug connector, it's a little loose feeling and the bottom isn't very tight, separation between outer jacket and inner jackets of the wires/plug. Could that cause this problem?

Going to try replacing that but though I would check in with the experts here. 🙂

Thanks

[Gene_Ginny]

You can verify that it is the shore cable by disconnecting the hot and neutral at the main circuit breaker in the camper where the shore cord connects. After disconnecting those 2, measure at the shore cord plug as you did earlier.

[DrewE]

You definitely have a short somewhere. If the meter is accurate and the readings are of a purely resistive connection (neither of which is at all certain), you'd have a short circuit current of somewhere in the range of 100A to 300A. Your circuit breakers may very well have prevented an electrical fire in your house—which is of course good, as that's exactly what they're there to do.

[westend]

Yup, your cord has a short in it or some part of the copper strands could be touching in the connector body. You may have some continuity from line (+) to neutral if a device is connected in a receptacle but you should have no continuity from neutral to ground or line (+) to ground as these are isolated in an RV in the former and should be isolated in the latter (unless you have a bad device connected in a receptacle).

The chewing mouse theory is gaining ground....

[love4god]

To answer a couple questions...

It is the house breaker popping, NOT a GFCI
I have tried different outlets on different breakers, they both tripped when RV Shore is plugged in. Other items work fine in the outlets I test and on the circuit so it definitely has something to do with the RV.

I'm editing this because I just went out and tested. I'm remember a little basic electronics and watched a youtube to test continuity.

So when i touch the prongs on the shore plug I'm getting continuity with them. When I touch the positive and neutral, the positive and ground, or the neutral and ground the circuit goes from OL to .4 to 1.2 ohms. So that means I have a short in that line somewhere, is that correct?

[westend]

AC circuit breakers will buzz before tripping. Seen it many times. It doesn't mean the problem is in the breaker. Like others said, you need to check the integrity of the shore cord. Break out the multimeter and check for continuity between the prongs of the male shore power cord, and also between the prongs and the entrance points in the 5'er.

New Rule: Nobody on this Forum is ever again allowed to refer to a receptacle or outlet as a plug.;)

[Bobbo]

If the buzzing is in the house, I bet the problem is in the house. Plug something else, not RV related into that outlet and see what happens. I bet whatever is buzzing is what is bad.

[DrewE]

If the main breaker in the RV is off, the fault would have to be before the breaker (or the RV's breaker is dangerously malfunctioning, which is not very likely). That generally limits things to the entrance cable, the EMS system if you have one, and the generator transfer switch if you have that.

The converter/inverter should be on the other side of the main breaker. Perhaps a large whole-house sort of inverter may be wired with a transfer switch before the main breaker, but I wouldn't think that's especially common.

If you have a multimeter, check the resistance between the various prongs of your RV power cable with the main breaker in the RV off. There should be an open circuit, or very nearly so if you have an EMS, between any and all of them.

[beemerphile1]

Is it an overload breaker tripping or a GFCI tripping? Be clear as to which in order to get relevant answers.

[mikim]

Check the house plug and make sure all of the screws are tight.

[love4god]

I think the buzzing is coming from the panel in the house, it's right in the garage and I open the door so I can hear it.

[wing_zealot]

If there is a buzzing sound when it pops the breaker, my first thought would be the converter is the source of the short.

[love4god]

Well, I swapped out the end plug tonight and still have the same problem. Unfortunately the cable is hard wired into my fifth wheel, it's not a male/female removable plug.

So next I guess I have to trace it up to the next connection and look for shorts.

It would have to be between the shore end plug and the inverter right? Because if ALL of the breakers in the RV are off, including the main breaker, it would have to be between where I'm plugging it in and the box?

[rhagfo]

Toddupton wrote:
Does it trip with the rv cord unplugged? That wifi tell you a lot.

I assume you were bit by auto correct! :B


He did state changed cords, and circuits, my guess is mice! Not sure how your shore power connects at the trailer, but likely a mouse has chewed the insulation off of a couple of wires. This would between where power inters the trailer to the beaker panel.

[Toddupton]

Does it trip with the rv cord unplugged? That wifi tell you a lot.