Shocking RV problem!

[jjrbus]

Original thread disappeared so starting new one.

Brief update,  I was getting minor shocks when working on RV frame.  I checked with multi meter and found I have about 30 volts AC from frame to mutimeter probe stuck in ground. I have posted this on a couple forums and coming up empty.

Back East Don, is convinced I have no ground to the chassis and gave me this test.

The test would be to use two extension cords.  One plugged into your campers electrical system and the other loose.  Then take your meter and measure AC voltage between the ground on the frame of the vehicle and the ground of the spare electrical cord.  If the meter is reading an AC voltage, your chassis is not AC grounded.

I attempt to perform the test but not sure what he means by loose?   An extension cord plugged into an outlet inside the RV and tested with a meter show's 39.7 volts with one meter probe in the ground side and other probe put in the earth.

[Back East Don]

56 minutes ago, jjrbus said:

I attempt to perform the test but not sure what he means by loose

Sorry.  Two cords plugged in to your AC from your house.  One of those will be plugged into the RV.  The other will not be plugged in(receptacle side not plug side) so you can apply your meter probe into the ground of the cord.  Test between the ground of the AC and the chassis of the RV.  You should be reading only nominal (meaning point something of a volt AC) voltage.  If you are still seeing 30 volts AC, your RV chassis is not bonded to the incoming AC ground.  The outlet ground will test fine with a tester but that is not where you are being shocked from.  The AC ground from your power center needs to be connected (bonded) to the truck chassis.

Edited July 26, 2016 by Back East Don

[jjrbus]

Thanks for the response.  I will check thoroughly tomorrow.

I have not put much though into chassis bond as I did it myself and not knowing what I am doing I am very careful about such things. 

I believe I added a new chassis bond and believe I left the old one connected?   

It was bugging me, so I went and looked I did not add a new chassis bond and used the old one. Looks like a solid #8 copper wire.  The ground wire in the shore cord is definitely connected to the ground buss in the new panel.

Now I have another thought.  I replaced the electrical panel in my house a few weeks ago.   I wonder if something in there is wrong?  

[Maineah]

Go buy a cheap 3 light tester they run about $5 at most any hardware store. Plug it in a see what it says. I leave one plugged in all the time I don't trust campground wiring. first thing first look at the cord cap (plug) and see if it has been replaced if it is not molded to the cord it's been replaced. If it has looking at the plug facing you the black wire should be on the right the white on the left and the green at the top. This is fairly common issue because people have a tendency to drive off with the cord still plugged in.Failing that open the load center cover (unplugged) and see how it's wired. There should be no white wires connected to green or copper wire there are two buss bars one for nothing but white wires the other for green or plain copper. The copper wire from the frame comes into the load center and joins the green and copper not the white.

[jjrbus]

11 minutes ago, Maineah said:

Go buy a cheap 3 light tester they run about $5 at most any hardware store. Plug it in a see what it says. I leave one plugged in all the time I don't trust campground wiring. first thing first look at the cord cap (plug) and see if it has been replaced if it is not molded to the cord it's been replaced. If it has looking at the plug facing you the black wire should be on the right the white on the left and the green at the top. This is fairly common issue because people have a tendency to drive off with the cord still plugged in.Failing that open the load center cover (unplugged) and see how it's wired. There should be no white wires connected to green or copper wire there are two buss bars one for nothing but white wires the other for green or plain copper. The copper wire from the frame comes into the load center and joins the green and copper not the white.

Thanks, I have the 3 light tester and have got a lot of use from it, I don't trust campgrounds or houses!  The panel is wired as it should be, I am thinking tomorrow I will do a continuity check on the shore cord.  I would do it now but it is lightning and thundering out.    Jim

[Back East Don]

11 minutes ago, jjrbus said:

I would do it now but it is lightning and thundering out.    Jim

Where is your sense of adventure?

[5Toyota]

where is your sense of adventure . I like that.   I have been involinterly inlightened  a few times over the years.

[Maineah]

The way the load center is wired there really should be no stray voltage the frame ground is a fail safe. If you have any thing plugged in.in the MH disconnect them and see what happens including the fridge plug. You have to be careful with a DVM they offer no resistance so often the readings can be a false positive. Using your meter check from the line side to your frame it should read line voltage that will verify the ground if you get no voltage do the same with the white wire and see what happens if that works your cord cap is wired wrong.

[jjrbus]

OK, cord cap is factory!   Here is what I have done so far.  I opened new house electrical panel to make sure ground is bonded to neutral, even checked with mutimeter and seems OK.

Nes I check ground wire in shore cord and it has continuity from plug to where it connects go ground bar in MH panel.

Then I connected a wire to ground buss in MH and checked frame to earth with multimeter and it shows 28 volts, when I touch wire connected to ground bus to frame where meter is showing 28 volts, meter goes to zero, which indicates ground is not connected to frame.

Then I checked ground wire with continuity tester and multimeter I ran my xtra wire from ground buss bar to frame and I show continuity with tester and  multimeter, to my way of thinking original ground wire is good?

While I was at it I checked shore cord for polarity, miswiring and shorts and it checks good.   For lack of any alternatives at the moment I am going to change the chassis ground connector.

Thanks   Jim

[jjrbus]

So where are you guy's?  55 minutes and no answer

I went out to clean up the ground to frame connector and decided it is a PIA and not worth it. There is about a 4 foot run to the panel so I took a piece of wire and new connector.  I cleaned  a spot with an angle grinder, hit it a lick with sandpaper and then chemically cleaned.

I attached the new #10 wire to the frame and ran it to the panel, leaving the old ground in place. 

And and, no voltage from frame, well 0.1 so Yippee we have success,  well not so fast,  I think this was an intermittent issue.   So will have to keep an eye on it.

[Back East Don]

6 minutes ago, jjrbus said:

So where are you guy's?  55 minutes and no answer

I went out to clean up the ground to frame connector and decided it is a PIA and not worth it. There is about a 4 foot run to the panel so I took a piece of wire and new connector.  I cleaned  a spot with an angle grinder, hit it a lick with sandpaper and then chemically cleaned.

I attached the new #10 wire to the frame and ran it to the panel, leaving the old ground in place. 

And and, no voltage from frame, well 0.1 so Yippee we have success,  well not so fast,  I think this was an intermittent issue.   So will have to keep an eye on it.

Sorry, I'm only semi-retired.  Had business to take care of.  I'm no genius but knew if the ground was good, there would be no AC voltage as it would be shunted to ground like it is supposed to.  That at least limits the problem to only a few points, plug, cord or connection unless your house ground is faulty also.  I didn't think it was the house ground because you indicated the outlets test properly.  This would make sense because the cord coming in is connected directly to the panel and so is the outlet.  Hence why I figured it was the ground to the  RV wasn't properly bonded.  Glad you found it.

[5Toyota]

nothing like a dirty cruded ground. have you seen any flickering lights before . can be a simtem of a bad ground.

[jjrbus]

1 hour ago, Back East Don said:

Sorry, I'm only semi-retired.  Had business to take care of.  I'm no genius but knew if the ground was good, there would be no AC voltage as it would be shunted to ground like it is supposed to.  That at least limits the problem to only a few points, plug, cord or connection unless your house ground is faulty also.  I didn't think it was the house ground because you indicated the outlets test properly.  This would make sense because the cord coming in is connected directly to the panel and so is the outlet.  Hence why I figured it was the ground to the  RV wasn't properly bonded.  Glad you found it.

Thanks for picking up on that and pursuing it,  I had given up on it.  I am still a bit confused by this as everything tested good, including the ground connection to the frame.  If I put a continuity tester on the bare ground wire near where it connects to frame and touch frame it show continuity and shows dead short with ohm meter.

[Back East Don]

Glad we didn't give up on it and I caught you mentioning it in another post.  Could be dangerous not having a properly grounded RV.

[jdfrost64]

mine did the samething.easy way is to get a gfi tester  to make sure your common and hot wires are ok .plug into shore power and test all recepts. more than likely  the 110 has the casing wore off . when you use the gfi tester just don't push the trip button. the tester will show you if all your recepts are working the right way. with mine I found that one of the 110 wires running to one of the recepts had wore a hole in the casing from when they ran it threw the wall framing. and the guy that owned before me just did a quick fix  and reversed the common and hot wire.it worked while you were in the mini .but you touch your bare feet on the ground or crawl under it .would knock the heck out of you.

[jjrbus]

8 hours ago, jdfrost64 said:

mine did the samething.easy way is to get a gfi tester  to make sure your common and hot wires are ok .plug into shore power and test all recepts. more than likely  the 110 has the casing wore off . when you use the gfi tester just don't push the trip button. the tester will show you if all your recepts are working the right way. with mine I found that one of the 110 wires running to one of the recepts had wore a hole in the casing from when they ran it threw the wall framing. and the guy that owned before me just did a quick fix  and reversed the common and hot wire.it worked while you were in the mini .but you touch your bare feet on the ground or crawl under it .would knock the heck out of you.

I tested this every way I could think of and also the way other people thought of!  After Don's test I knew I had an issue but still could not find it as the ground wire was testing good with a multimeter and continuity tester, was also not having an issue with the installed gfi or an added gfi.

You would have quickly  found you had a problem with a three light tester, such as this one. This will only tell you there is a problem not where the problem is.  I use it at RV parks before plugging in and used it on every outlet in my house when I bought it and of course went through the RV with it.

These are available everywhere from $5 and up.                      HTH  Jim

 

 

Edited July 28, 2016 by jjrbus

[Maineah]

19 hours ago, jjrbus said:

OK, cord cap is factory!   Here is what I have done so far.  I opened new house electrical panel to make sure ground is bonded to neutral, even checked with mutimeter and seems OK.

Nes I check ground wire in shore cord and it has continuity from plug to where it connects go ground bar in MH panel.

Then I connected a wire to ground buss in MH and checked frame to earth with multimeter and it shows 28 volts, when I touch wire connected to ground bus to frame where meter is showing 28 volts, meter goes to zero, which indicates ground is not connected to frame.

Then I checked ground wire with continuity tester and multimeter I ran my xtra wire from ground buss bar to frame and I show continuity with tester and  multimeter, to my way of thinking original ground wire is good?

While I was at it I checked shore cord for polarity, miswiring and shorts and it checks good.   For lack of any alternatives at the moment I am going to change the chassis ground connector.

Thanks   Jim

OK you say bonded to the neutral it should not be. The neutral should contain nothing but white wires and should be isolated from the metal work including any ground wires. If the box is new it is possible it has a ground screw bonding the neutral buss to the box that should be removed. Most  new boxes don't come with a ground buss it is some thing that has to be added, the buss that is there is a neutral buss usually there is a screw provided to ground that buss to the box but it the case of a sub panel (your MH) it is not used. The logic of this is improper wiring from another source if the feed and the neutral are reversed your box/frame could become hot in theory it should trip the breaker but if the ground is bad or non existent every thing has a line voltage potential including all DC circuits grounds metal siding etc.

[jjrbus]

16 minutes ago, Maineah said:

OK you say bonded to the neutral it should not be. The neutral should contain nothing but white wires and should be isolated from the metal work including any ground wires. If the box is new it is possible it has a ground screw bonding the neutral buss to the box that should be removed. Most  new boxes don't come with a ground buss it is some thing that has to be added, the buss that is there is a neutral buss usually there is a screw provided to ground that buss to the box but it the case of a sub panel (your MH) it is not used. The logic of this is improper wiring from another source if the feed and the neutral are reversed your box/frame could become hot in theory it should trip the breaker but if the ground is bad or non existent every thing has a line voltage potential including all DC circuits grounds metal siding etc.

 

I wish I knew more about this, I rely heavily on people such as yourself for input or I would be totally lost.   The grounding screw in the new box in the house threw me and had to call someone to make sure it was as it should be.    Thanks Jim

[Back East Don]

53 minutes ago, Maineah said:

OK you say bonded to the neutral it should not be. The neutral should contain nothing but white wires and should be isolated from the metal work including any ground wires

Just to clarify in case Jim isn't reading this clearly.  I know Jim was also looking at the work of his electrical panel which was recently replaced.   In a sub panel the ground is isolated from the neutral but in a main panel, like in your house it is usually not.   Treat the RV as a sub panel and keep the two separated with the AC ground bar bonded to the frame.  The RV relies on the incoming cord ground for safety as the RV has no inherent ground as it is isolated by the tires.  If you have the neutral connected to ground in the RV, it does indeed need to be isolated from ground for safety.  Clear as mud right?

[Maineah]

That is correct the house panel is generally not a sub panel. The exception is if it is behind a breaker/disconnect.They make meter panels with a breaker disconnect then the house panel becomes a sub panel. My response was only directed to the motor home panel it all ways is a sub panel. I was under the impression it had been replaced how ever it is the first place to look for what he is trying to track down. These things have been around a long time allowing MH owners plenty of time to tinker. If it is  indeed a grounding issue it starts at the house (unlikely other wise the house would have issues) that leaves every thing from the MH plug to the MH frame. What I believe I would do is drag the camper power cord inside (unpluged), open the MH panel box and check every connections continuity from the plug to the frame. Looking at the plug the hot is on the right (black wire) the neutral is on the left (white wire) the ground is at the top (green wire). Check each one then check them again to make sure it does not show up on two connections. Then look at the buss bars they will have to be all white wires on one and all green/copper wires on the other.

[Back East Don]

2 hours ago, Maineah said:

My response was only directed to the motor home panel it all ways is a sub panel.

Just trying to make it as clear as possible for Jim as he at one point wasn't sure what point to suspect.  He connected a new ground to the chassis and the problem seems to be gone.  Will know better once he reports back and also perhaps he'll double check that everything is separate. 

 

2 hours ago, Maineah said:

They make meter panels with a breaker disconnect then the house panel becomes a sub panel.

Why I said usually but didn't go into depth as I didn't think the issue was his house panel because the ground tested good at the outlet in the RV.  Also didn't want to confuse things further.  Amazing what you learn building a couple of houses.

[jjrbus]

This is getting ridiculous!   I go out this AM and decide to check frame to ground voltage and show a whopping 46.9 volts!  That is a new record.

So I turned off all circuit breakers in the Toy except the 30 AMp main breaker.  and turn on one at a time and then shut off before turning next one on, so only one breaker is on at a time.

1. AC breaker       14.1 volt   at multimeter

2. general circuit        8.7  volt

3 general circuit          2.7 volt

4  general circuit       4.6  volt

All back on and show   39.2 volts

I am completely stumped and pretty disgusted.         Jim

Left click on photo to enlarge

[Back East Don]

19 hours ago, Back East Don said:

perhaps he'll double check that everything is separate. 

Looks like you are measuring dirt there.  Your RV electrical panel outside?

45 minutes ago, jjrbus said:

decide to check frame to ground voltage and show a whopping 46.9 volts

What does this measurement read inside the panel in the RV measuring neutral to ground, hot to neutral and hot to ground?  Those are the measurements that matter.  If measuring the outside RV to earth, you need to take the measurement on something metal that is penetrating deeper into the soil than that probe in the dirt.

Edited July 29, 2016 by Back East Don

[jjrbus]

Probe in dirt is about 1 foot away from house ground rod, I get the same reading at ground rod that I do from probe in ground.

Hot to neutral      119.8 V

Hot to  ground     75 V

Neutral to ground  39.1 V      Same as frame to ground rod.

I am removing one wire at a time from neutral and ground looking for difference?   Slow process.    Jim 

[jjrbus]

Little bit of an update.  I have been removing, putting back on wires, plugging and unplugging. Pulled all the neutrals, all the ground, measured every thing 6 ways to Sunday, took back out reinstalled and finally found an abnormally.  Maybe, this is an intermittent problem, remember?

I have multimeter connect to frame and other probe stuck in ground.  It is reading 27.4 V, I pull the 20 amp AC breaker and the meter drops to 4.l7 V.   I put the breaker back in and meter still reads 4.7V, anyone want to trade a motorhome for a set of golf clubs?

Not to be deterred I turn the AC on and the meter shows 27.4 again.  

I have no idea what this means or what I should do now?      Jim

[Back East Don]

3 minutes ago, jjrbus said:

anyone want to trade a motorhome for a set of golf clubs?

I've got clubs and a motorhome already.

First try the same test to the electrical cord you are plugging the RV into.  You may have already done this I just don't remember.  Should be zero between neutral and ground on the plug as well as the outside grounding pole.

Do that and let me know while I mull this over.  Need lunch actually.

[RVdaytrader]

Hotdamn!!!...I just happen to have a complete new set of golf clubs my wife bought and never used!!...when can we make the trade???

[jjrbus]

Work, lunch, sleep your just loaded with distractions.  No wonder you left the orbits all loaded with junk!

Well testing is on hold for a bit I am back to 0.01 V from frame to ground?????   At this point I have to be suspect of the old roof air.   Jim

[Back East Don]

3 hours ago, jjrbus said:

At this point I have to be suspect of the old roof air

While I ate my distraction, I gave this my divided attention as I considered what I am going to do about supper tonight.

The two most likely candidates in my way of thinking would be either the fridge or AC.  I was thinking more likely fridge and here is my logic.  The AC is direct wired (although if you have easy enough access, it might not be a bad idea to check those connections).  The fridge on the other hand is plugged into an AC outlet and not direct wired.  Nagging at me though is it doesn't isolate with the breakers.  Don't know if you tested the outlet for the fridge or if it is one of those crappy plastic pos that came in mine that I replaced.  What else is left besides the power center's DC supply?  No really, what's left that is plugged in?

Edited July 29, 2016 by Back East Don
clarity

[jjrbus]

I would be suspect of the fridge also, have read that the electric heating elements can cause issues. But the fridge is unplugged, I also replaced the crumbly, corroded broken RV outlet at the fridge.

I have looked over the progressive Dynamics converter install and ground and common buss bars and see nothing I have done wrong.

It is intermittant so I am leaning towards the roof AC or the converter.   Seems I need to jury rig a light or meter to notify me when it is happening.   

Can't help but wonder how many have this issue that are unaware of it?       

  Jim

[jjrbus]

3 hours ago, RVdaytrader said:

Hotdamn!!!...I just happen to have a complete new set of golf clubs my wife bought and never used!!...when can we make the trade???

Stonehedge ,  High Noon the 15th. 

[WME]

OK is it the RV or the house????????? Go to a friends plug in there and check. At least you'll get half the problem solved.

 

[jjrbus]

Good idea, but it is an intermittent problem.   Jim

[fred heath]

That small of an amount of voltage, especially using a digital meter is nothing to worry about.

It could be caused by any # of things. If you did the test with a analog meter you would probably get a "0" reading.

[jjrbus]

7 minutes ago, fred heath said:

That small of an amount of voltage, especially using a digital meter is nothing to worry about.

It could be caused by any # of things. If you did the test with a analog meter you would probably get a "0" reading.

As soon as I have reading again I will try with an analog meter.  The electrical guy's are telling me it is a phantom voltage.  I noticed this as I am getting shocked when working on frame so thinking there is nothing phantom about it!