Hot neutral

[PapaBubbee]

I have a 2017 keystone montana 5th wheel. During Thanksgiving we had a issue with 240v on our plugs. No breakers tried and had 120vac between ground bar and neutral bar in camper. Ended up unplugging the camper checked voltage on cord and was good. Plug back in everything OK same thing happen next day unplugged and replug everything OK tonight it happen again now back to normal. Do have 120+or_ milli volts difference removed surge protector last time thinking that was problem. Not sure what to do next

[bshgto]

Originally Posted by PapaBubbee

I have a 2017 keystone montana 5th wheel. During Thanksgiving we had a issue with 240v on our plugs. No breakers tried and had 120vac between ground bar and neutral bar in camper. Ended up unplugging the camper checked voltage on cord and was good. Plug back in everything OK same thing happen next day unplugged and replug everything OK tonight it happen again now back to normal. Do have 120+or_ milli volts difference removed surge protector last time thinking that was problem. Not sure what to do next

Remove the shore power cord receptacle and look for burned loose wires then trace the wiring from the outside plug to the panel ( you`ll have to remove the colorplast) look for damaged wire rubbing on something then look for loose burned wires in the panel. I`m sure you`ll find the problem.

[BB_TX]

Sounds like you have an open neutral, meaning loss of connection of neutral from your trailer to your source. If neutral is not connected, then it is also not connected to ground. And metering would show 120 vac neu to gnd. That can also possibly damage some of your 120 vac devices depending on how badly the voltage varies on the two different legs.

Since plugging/unplugging temporarily corrects the problem, I would guess there is a loose neutral wire connection either in your power cord connector or in the outlet you are connecting to .

One of these is handy to have for troubleshooting purposes.

https://www.homedepot.com/p/Receptac...E&gclsrc=aw.ds

[PapaBubbee]

Just got done checking cord and where it plugs in OK. When everything is working I still get milli volts between ground and neutral I get almost 2 ohms resistance between ground and neutral

[PapaBubbee]

I do have one of those testers and all the plugs I checked are ok

[BB_TX]

Originally Posted by PapaBubbee

Just got done checking cord and where it plugs in OK. When everything is working I still get milli volts between ground and neutral I get almost 2 ohms resistance between ground and neutral

A poor wire connection could give that resistance and milivolt reading.

First I guess I would check the wire connections on the trailer shore power connector. There have been a lot of loose wire connections reported there, many with burned connector pins due to overheating because of resistance due to wires not properly secured.

Originally Posted by PapaBubbee

I do have one of those testers and all the plugs I checked are ok

Did you try the tester when you were actually experiencing the problem?

[Daryles]

What Bshgto said.
If it all looks good, disconnect the water heater electric element wires. Put wire nuts on them for safety.
Put power on and do your tests.
If good, change the element.

[PapaBubbee]

Might have found the problem. Friend came over with his cord,plug it in voltage gone plug mine back in voltage back plug his back in voltage gone. Will get a new cord. Thanks everyone for the help

[BB_TX]

Originally Posted by PapaBubbee

Might have found the problem. Friend came over with his cord,plug it in voltage gone plug mine back in voltage back plug his back in voltage gone. Will get a new cord. Thanks everyone for the help

Likely you have a loose/bad neutral wire connection in one end of that power cord. Since it is bad already, open up the connectors on both ends and check the wire connections.


Hopefully no damage was done to anything in the trailer.

[Bourbon County]

Could you answer a few questions?
1. Are you parked in a campground or is this a 50A outlet installed at your home?
2. You stated you had 240v on a 120v outlet, was this actually measured with
a meter?
3. What surge protector do you have? Most of them will detect an open neutral.
4. What electrical appliances/loads were running when this anomaly occurred?

By code, a neutral is grounded at the service entrance point wherever you are and is supposed to remain solid throughout any distribution circuits. This is the point in the system that offers the lowest impedance connection and will be common with the entire system. By symptoms described this certainly sounds like an open or high impedance neutral. There should be a good neutral connection at the pedestal you're plugged into. You can't really establish a neutral in the RV, it's possible to lose it in the RV.

You stated that you could unplug your cord and plug it back in and the problem would clear for a period of time. You later stated when you plugged your friend's cord in, it cleared. If you didn't leave your friends cord plugged in for a while, I'm not sure you really proved anything if you didn't leave it for a time.

I think the 50A outlet on the pedestal would be the best place to start, use your meter and confirm you have a good neutral there. Those 50A male plugs take a substantial amount of force to plug in and if the receptacle is not mounted securely you might be moving it enough to cause a poor connection to get worse or even open. If you're convinced it's your power cord, you can buy either or both the male plug or twist-lock female separately and would be much more affordable than a whole new cord. Unless the cord has visible damage, it's likely good. The female twist-lock power inlet on your RV is another likely suspect.

Open neutrals are often a real head scratcher, they can manifest a long way from the source of the problem; if they are intermittent it's even harder to find. For future reference if you're using a digital multimeter, they can at time lie to you, even high end expensive models. These meters offer a very low impedance and are just not accurate sometimes; you need to put some load (resistance) across the circuit. In an instance like measuring voltage between the ground and neutral bus in your RV panel, an old fashioned pigtail light socket with an incandescent (not LED) light bulb makes a really good tester. Get a rough service coated bulb for safety if it should shatter.

[PapaBubbee]

We are at a private campground. Camper is permanently set up, and has been for 2 years. At the time this happened we had a heavy load. Stove tv fireplace electric heater and went too turn on microwave which kicked off tried it 3 times than ceiling light got bright and burnt out.checked plug in found 240 between hot and neutral. Opened breaker box found 120 between ground and neutral. I had a fluke volt meter. Trunked off breakers and still had it. Unplug cable and plugged back in everything fine. Same thing happen again next day. Same result. No problem until about a week later under slight load. Next day checked everything from meter to cord receptacle plugged back in 80 volts between ground and neutral. Couldn't get rid of it until tried different cord.new cord on order when I get back . Camper is unplugged for now . Battery charger on batteries

[richeyb]

We had a similar problem with our 2017 HC. I finally traced to the connection at the trailer. Apparently I had not got it connected good which resulted in arcing and burned the wires at both ends of the connection; the cord and when I pulled the female connection on the fifth wheel. Wires were burned for a couple inches into the Coach body. Ended up replacing both connections clipping off the burned wiring.. Fixed my problem.

[rohrmann]

An excellent investment to protect you and your rig is a hardwired EMS, such as https://www.progressiveindustries.net/ems-hw50c
When installed inside your rig, you will be protecting everything up to the EMS device and failures in wiring up to the device will be stopped at the EMS. We've had ours for quite a few years and even a failed extension cord connection never made it to the inside wiring.

[twindman]

Originally Posted by rohrmann

An excellent investment to protect you and your rig is a hardwired EMS, such as https://www.progressiveindustries.net/ems-hw50c
When installed inside your rig, you will be protecting everything up to the EMS device and failures in wiring up to the device will be stopped at the EMS. We've had ours for quite a few years and even a failed extension cord connection never made it to the inside wiring.

Picture -- Yowzer!!!! That wasn't good

[richeyb]

Originally Posted by rohrmann

An excellent investment to protect you and your rig is a hardwired EMS, such as https://www.progressiveindustries.net/ems-hw50c
When installed inside your rig, you will be protecting everything up to the EMS device and failures in wiring up to the device will be stopped at the EMS. We've had ours for quite a few years and even a failed extension cord connection never made it to the inside wiring.

Bob, Totally agree, I installed a Progressive EMS right after I purchased. Almost positive it has saved my bacon several times. When installed it is always working and you don’t takeoff for home and forget it!