Hot Skin

[Jerry Emert]

My Son got a little tingle when he touched the lock on the entry door today while preparing to leave for Alaska tomorrow.  I think I tracked it down to the power cord.  With the power cord not plugged into my house 50 amp outlet, I get .565K Ohms between the white and black at the surge protector in the bay.  Also have approx. the same between the neutral and one of the hots on the male plug of the power cord.  Open between the other hot and neutral.  How do I get into the cord reel box to check that connection. Probably easier than taking off the molded plug to check it.  No heat damage noted on the plug.  I did bring the plug out to full extent, just as I saw red tape on cord yesterday so maybe?  Thanks
Jerry

[Keith Moffett]

Jerry
Not sure if the '03 power cord was a reel or coiled into a bucket.  Both would be electric but the difference is the connections on the reel type.  Those were always suspect. 

[Jerry Emert]

It's a bucket, I found it and easier than I thought.

I think I may have been on the wrong track.  I took blk wire off the surge protector and the .5K Ohms is coming from the surge protector.  Line one is where the control circuits in the surge gets it's operating voltage so that explains that.  With the blk off the surge, it is now open between blk and white on the cord.  Since then, I have turned every breaker in the coach off and then on again measuring the AC voltage every step of the way.  Basically every breaker I turn on gives me just a little more AC on the skin.  The biggest is the inverter at about 13 VAC.  I'm not too sure of my theory at this point.  My training was on ships, nothing with real dirt outside.  I was told to actually use ground, actually the ground the RV is on for my readings.  That is what gives me 15 VAC total with all breakers on.  Measurements on the inverter between ground (12 VDC black) and green (chassis ground) are all showing zero VAC as I think they should.  So with my 18 months of electronics training and 20 years of experience I think I'm stumped.  Any ideas?
Jerry

[Steve Huber Co-Admin]

Jerry,
Sounds like you've got an open neutral or ground. Try using your 30A plug to supply shore power. It uses the neutral wire so if the Ac voltage on the door disappears, it's an open or resistive ground connection. If symptoms don't change, it is probably an open ground. If  you have a plug in AC checker, it also may tell you what the problem is.  https://www.amazon.com/Power-Gear-3-Wire-Receptacle-50542/dp/B002LZTKIA/ref=sr_1_1?ie=UTF8&qid=1490996802&sr=8-1&keywords=AC+checker

Best candidate is the cord reel. Try running on generator power. If problem disappears, it's cord  or cord reel.

Steve

[Jerry Emert]

Solution, I think?  I apparently started at the wrong end.  I had a 50 Amp connection put in at my house last year before we left for the summer.  If Mike Sokol of the "no Shock Zone" on Youtube is correct, I have a reverse bootleg ground in the new 50 Amp connection.  Using a non contact voltage tester as he shows seems to indicate the reverse bootleg ground.  The voltage tester goes nuts 2 or 3 inches from the whole box.  My house has 3 prong outlets throughout so I'm pretty sure the electrician just didn't do it right.  Of course it's been a year now so I'm stuck with it.  Everything works when the genny is running with no stray AC anywhere.  Heck everything works while plugged in too if you don't mind a little tingle when the ground is wet!  So I guess I will know for sure at the first Campground we come to.   Thank you to all who tried to figure it out.  I guess we will leave Sunday instead.  Thanks to Keith I learned that I have a bucket for my power cord and not a reel.  Sounds like a good thing.

[Lee Welbanks]

Jerry, Here is a very handy link to electrical for RV's and about any other thing you can hook to a power outlet.
http://www.myrv.us/electric/

[Edward Buker]

Jerry,

Trying to sort out the stray current path is never really easy on one of these issues. If you break down what is happening, when you are standing on the ground and get a "hot skin" affect it means you are part of the circuit being completed, that is AC current is passing through your body.  The generator case does not tell you too much about the source of the issue. The coach sits on 6 or more insulators (tires) and there is no current path from the generator to earth ground so even if the skin was hot you would not feel it standing on the ground nor would you be able to measure it as being hot using earth as a ground reference, it is just not in the circuit that you would be part of.

The transfer switch isolates the hot and the neutral lines with a relay contact so when you run the generator everything that is actively hot and in the circuit includes the whole coaches wiring system except the AC feed cord system up to the transfer switch. The point of this is somewhere in the coach there could still be a path of current leakage to the ground/neutral system that is only sensed when earth ground is in the circuit on shore power.

What is trying to be achieved at the 50 amp outlet that you are plugging into is a resistance free connection set to the hot lines, the neutral, and the pedestal wired ground and earth ground. Is the 50 amp outlet that was added wired right? Is the ground and neutral connections tied back to the source with tight well greased weatherproof connections and is there an 8ft ground rod with a good copper ground driven into earth ground and well clamped at the 50 amp outlet point that you plug into. Along with your concern that you raised about the reverse bootleg ground verify that everything is wired right.

Getting to the basics, the skin and frame of the RV is supposed to be at the same potential (voltage) as earth ground and will be if all the connections are made and are resistance free. I would be measuring ohms with the coach plugged in, with the 50 amp breaker off that feeds the 50 amp outlet.

See if everything is tied together without resistance. This may take a long spare wire for measuring.

Measure ohms from the 50 amp outlet ground to the coach frame, measure ohms from the ground rod to the outlet ground, measure ohms from the outlet ground rod to the coach frame, measure ohms from the neutral to the coach frame, measure ohms from the neutral to the ground rod. You may also want to check at the coach main ac power panel, the ohms of the neutral and ground back to the plug in ground and neutral. Also from the coaches ac panel neutral and ground ohms to the coach frame. I think both the neutral and the ground in these coaches is bonded to the frame but they may not all be wired that way.

See if the results indicate that all connections indicate that earth ground and the coach should be at the same potential or not. If you have a hot skin obviously something is not right with these connections.

Later Ed

[Jerry Emert]

Thanks Ed, I did all or most of those measurements.  All were as they should have been.  There isn't a separate copper grounding rod in the ground for my 50 amp panel.  I'm sure the house has one by the main panel to the house.  The only way I got any abnormal readings was using the non contact voltage tester as demonstrated in the Youtube video I mentioned above.  The 50 amp panel I had installed makes it go crazy.  All my house outlets and main panel do not.  I'm sure that the electrician did something that may be acceptable in homes, or maybe not, but doesn't work for RV's.  Or maybe something just broke.  I did not want to dig any deeper because we are trying to get on the road for Alaska.  The coach was running on the genny all day today with no problems or "tingles."  I'll just have to get an electrician involved in November when we get back to Florida.  My non contact voltage tester is now velcroed to my bay door where I keep all my "set up items."
Thanks for your help.
Jerry

[Darell T Hostland]

Certified Master electrician for 40 years. 20years of power quality testing on UPS systems and emergency generator systems. 5 ma across the heart at very low voltages as on the frame of your rv will kill you. Be very carefull where you step and where you touch the rv.

[Edward Buker]

Jerry,

Those measurements I mentioned are certifying that the AC supply side has those proper connections wherever they originate. In your case in order to know you would have to measure from the new 50 amp outlet back to the ground rod and ground bond connection points, as well as the neutral bond points which would be back at the main AC panel box/meter area. For instance you would measure the ohms from the house ground rod to the main house panel ground buss and from that buss out to your outlet etc.

I would without a doubt add a supplemental ground rod to the outlet area and also bond that to the ground grid that you verify is connected properly back to the house supply.

This will all wait until you get back from Alaska, enjoy your trip.

Later Ed

[Jerry Emert]

Ed, I measured ground rod to the main panel and it was good.  I did not measure ground rod to the new panel because it's on the other side of the house.  I made measurements on the RV panel.  All measurements were good so I initially ruled the panel out.  I did not want to open the panel and create more problems for myself once I figured out what I think is going on.  I'm guessing the electrician just tied the neutral and the ground together in the panel as noted in the video.  It will be my first project when I get home.  This little tool, non contact V tester, should be in every RVer's tool box, maybe it is.  It is apparently the easiest way to tell if you have one of these bootleg grounds.  It's funny that I did use it near the beginning to see if power was coming through the switch.  I had not really figured out what I was doing kind of just trying to get on track.  Anyway it kept going off every time I even got close to any of the AC wiring.  I put it away because I thought it was broken or something.  2 hours later, after watching the video, the proverbial light bulb came on and I broke it out and verified the problem.

https://www.amazon.com/Sperry-Instruments-VD6505-Non-Contact-Sensitivity/dp/B000GLAC5G/ref=sr_1_1?s=electronics&ie=UTF8&qid=1491140746&sr=8-1&keywords=sperry+non+contact+voltage+tester

Thanks again
Jerry

[Lee Welbanks]

Jerry, Turn the breaker for this circuit off and lock it out if you can, get a qualified electrician to check this out, there are a lot of electricians that don't understand how a Rv 14-50R circuit has to be wired. I would love to see inside the panel of how this is wired.

[Jerry Emert]

I've heard horror stories also and passed my concerns on to him at the time.  He seemed knowledgeable.  I've had the coach plugged in for there for months with no damage.  It took my 10 year old standing in a puddle and touching the door lock to show up.  Just happy that it wasn't a higher charge.  When he found it he called his Sister and Mom over and tried to get them to touch it.  They were smart enough not to.  Of course when he told me I walked right up and did it!  When I didn't feel anything I put one hand in the puddle and one on the lock.  Sometimes I wonder how I lived so long!  I was taught in the Navy by my first Boss to check fuses by licking 2 fingers and touch both sides of the fuse!  If you get bit it's bad.  Next November we will find out.  Thanks!

[Edward Buker]

Jerry,

Never decide to do a "human test" and absolutely never allow the path to be through the heart. One hand on the RV skin and one in a puddle is probably a worst case scenario as to how to set up a heart stopping shock.....an AC voltmeter lead in the puddle pressed into the ground a bit, and a meter lead on the skin next time for sure.

Later Ed

[KC Snellgrove]

Jerry, I would not hesitate  to contact that electrician and tell him the issue. I bet he will glady take care of his  mistake. Let  me know.