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Line voltage meters - low voltage

Hi,
I'm having an issue with my coach when plugged into a 120v 20Amp circuit. The line voltage meters inside the coach are displaying 65 volts. If I disconnect from the line and run the generator, they are displaying 120 volts, just like they are supposed to.

Here's what happened earlier today. We were putting a bulk charge into our lithium batteries, which takes some juice. I forgot that the electric water heater was also on. I ran the microwave and we blew the breaker in the building we are plugged into. We have been having this problem ever since that happened. The breaker in the building was reset and I checked the voltage at the end of my cord and it is 120 volts.

I checked the breakers under the bed and all are good. Also reset the mains under the bed. So, there has to be something in the coach that is only allowing half of my voltage to come through. I have the coach unplugged from the line voltage for now and am just running off of batteries until I figure out what it causing this issue. Any ideas?

Thanks,
Kevin
Kevin and Donna
2000 Foretravel U295 Build #5613
2002 Jeep Wrangler
Motorcader #18561

Re: Line voltage meters - low voltage

Reply #1 –
If you run the generator while charging you batteries is the voltage ok? If so try setting your charger to 5 or 10 amp max draw
Bruce, Linda, and Macy
Zoey RIP 1/20/19
1999 U295 40' build #5400
2017 silver Jeep Wrangler, 1260 watts of solar on top
Moving around the country

Re: Line voltage meters - low voltage

Reply #2 –
If you have verified 120 VAC at the coach end of the shore power cord, next place I would check is the ATS.

With shore power disconnected, generator off, AGS off, inverter off, remove the lid to the ATS.

Verify that all screws securing the wires are clean and tight and no wires are burned.

This is actually part of my annual Preventive Maintenance list.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Line voltage meters - low voltage

Reply #3 –
It's possible the high current draw could have overheated/damaged the extension cord socket. The brass connector clips lose their grip and then have high resistance. Something easy is try another extension cord.
Peter and Tammy Fleming
1991 U300 GV 40 - Sold, owned for 4 years
Downsized to Roadtrek Popular 210 class B

Re: Line voltage meters - low voltage

Reply #4 –
I checked everything you guys mentioned this morning. Thanks for the replies! Everything checked out, so I pulled the power line monitor out and checked the voltage where they are plugged in. 120 volts! So I guess the only issue is the monitor is bad. Strange that it would go bad all of the sudden. Has to be an explanation for that.

I also noticed that I have.two ATS's, stacked on top of one another. Rather difficult to get to the bottom one so I didn't bother trying to get to it.

Kevin
Kevin and Donna
2000 Foretravel U295 Build #5613
2002 Jeep Wrangler
Motorcader #18561

Re: Line voltage meters - low voltage

Reply #5 –
Quote from: kjsifer –
I also noticed that I have.two ATS's, stacked on top of one another. Rather difficult to get to the bottom one so I didn't bother trying to get to it.
Kevin

Yup, two ATS's:

#1 Shore power OR generator.
#2 Power from #1 OR from inverter
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Line voltage meters - low voltage

Reply #6 –
Quote from: kjsifer –
So I guess the only issue is the monitor is bad. Strange that it would go bad all of the sudden. Has to be an explanation for that.
Kevin

You would not believe how many time I have heard this in my career as an electrical and low voltage contractor. For some reason they always thought no mater what it was that stopped working or burned up was my fault.

Can anyone think of one thing the worked on their coach one minute and the next it didn't.
2014 ih45  (4th Foretravel owned)
 1997 36' U295 Sold in 2020, owned for 19 years
  U240 36' Sold to insurance company after melting in garage fire
    33' Foretravel on Dodge Chassis  Sold very long time ago

Re: Line voltage meters - low voltage

Reply #7 –
Strangely, the voltage meter is working great again. I can say I've never seen such erratic behavior from an electrical device. Usually, once it goes bad, it stays bad!

Kevin
Kevin and Donna
2000 Foretravel U295 Build #5613
2002 Jeep Wrangler
Motorcader #18561

Re: Line voltage meters - low voltage

Reply #8 –
Quote from: kjsifer –
Strangely, the voltage meter is working great again. I can say I've never seen such erratic behavior from an electrical device. Usually, once it goes bad, it stays bad!

Sounds like there could be a loose neutral or ground somewhere.  Voltage is a relative difference from the reference, not an absolute quantity.  If there is not a good connection to that (or if there's stray voltage on the ground wire), you'll get some whacky readings.

I would not close the book on this one.
Learn every day, but especially from the experiences of others. It's cheaper!  - John C. Bogle

2000 U320 36' non-slide / WildEBeest Rescue
2003 U320

Re: Line voltage meters - low voltage

Reply #9 –
Great observation Michelle. I believe I do have a grounding issue somewhere. I had the water heater out yesterday, and, while the rig was plugged in, I felt a current on the propane line that attaches to the water heater. Not good!

Where is the typical problem area for this issue? There are so many wires I wouldn't even know where to begin to look.

Thanks
Kevin
Kevin and Donna
2000 Foretravel U295 Build #5613
2002 Jeep Wrangler
Motorcader #18561

Re: Line voltage meters - low voltage

Reply #10 –
I think I'll start by replacing the plug on the end of my extension cord. I noticed in the last few days it has been a little warm to the touch and can actually get quite warm if I'm pulling a large current. Other than that, not sure where to start.

Kevin
Kevin and Donna
2000 Foretravel U295 Build #5613
2002 Jeep Wrangler
Motorcader #18561

Re: Line voltage meters - low voltage

Reply #11 –
Quote from: kjsifer –
Great observation Michelle. I believe I do have a grounding issue somewhere. I had the water heater out yesterday, and, while the rig was plugged in, I felt a current on the propane line that attaches to the water heater. Not good!

Not good indeed!  That's a "hot skin" condition and can be deadly (volts jolt but mils kill - milliamps, that is).  Be careful that your body isn't the conductor that completes the circuit. 

Quote
Where is the typical problem area for this issue? There are so many wires I wouldn't even know where to begin to look.


Starting with your plug/extension is a good start since you mention it gets excessively warm.  That indicates too much resistance in that area/too high of a current for the conductor it's flowing through.
 If it's a molded plug, those are notorious for bad connections.  Not just the extension cord but also the plug on the coach power cord as well.  Those are the easiest to start with.
Learn every day, but especially from the experiences of others. It's cheaper!  - John C. Bogle

2000 U320 36' non-slide / WildEBeest Rescue
2003 U320

Re: Line voltage meters - low voltage

Reply #12 –

If you don't have one, available at any hardware/home improvement/walmart or same day on Amazon. This might tell you what to look for, starting at the building outlet.

Klein Tools RT110 Outlet Tester, AC Electrical Receptacle Tester for North American Outlets Klein Tools RT110 Outlet Tester, AC Electrical Receptacle Tester for North...

As an Amazon Associate Foretravel Owners' Forum earns from qualifying purchases.
Peter and Tammy Fleming
1991 U300 GV 40 - Sold, owned for 4 years
Downsized to Roadtrek Popular 210 class B

Re: Line voltage meters - low voltage

Reply #13 –
That is a great tester! Best bang for your buck.
Richard & Betty Bark & Keiko our Golden Doodle
2003 U320T 3820 PBDS
Build # 6215
MC # 16926
2016 Chevrolet Colorado 4X4 diesel

Re: Line voltage meters - low voltage

Reply #14 –
Kevin,

If you have a cord reel you need to check to see if the Natural brush or holder has failed. If you have a twist lock at the bulkhead instead of a reel take both sides apart and check for failed connections. As has been said above this "hot skin" is something that has to be found and fixed as this can be deadly.

Mike
Pamela & Mike 97 U 320

"It's not what happens to you, but how you react to it that matters."

Re: Line voltage meters - low voltage

Reply #15 –

I don't have a cord reel.

I did replace the receptacle on the end of the extension cord that I am using and it is no longer heating up. I think that was the problem.

 I also bought one of those outlet testers and all my outlets are testing fine. They had these at Lowe's for $10.......Fluke ST120 GFCI Socket Tester Without Beeper: Amazon.com: Tools & Home...

Kevin

As an Amazon Associate Foretravel Owners' Forum earns from qualifying purchases.
Kevin and Donna
2000 Foretravel U295 Build #5613
2002 Jeep Wrangler
Motorcader #18561

Re: Line voltage meters - low voltage

Reply #16 –
If your going to change plugs and sockets check out the Smart plug,much better then the stock plug.
96 U270 BUILD 4810
85 380SL
Drummonds TN.