Tips on Finding Hot Skin Source - R-pod Owners Forum

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Grant177

Groupie

Joined: 15 Mar 2020
Location: Edmonton, AB
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Posts: 65

Topic: Tips on Finding Hot Skin Source
Posted: 26 Jun 2020 at 9:32am

OK....so last camping trip, while plugged into a 30A receptacle, I went to tie down a screen tent rope to the trailer as there was some light rain (wet ground) and winds were picking up. I touched the trailer frame I got zapped...

Quickly took out the multimeter and was getting about 90v AC from frame to earth (just sticking the mm probe into the dirt).

Immediately unplugged the trailer, but did a couple more tests when it was safe to do so and confirmed the frame is hot...

An AC plug tester in the trailer outlets showed everything OK (though I don't know if a household outlet tester is ideal for testing a trailer receptacle?).

I am going to where I have it parked now and will start testing everything I can find, but wondering if anyone has any good tips where to start etc? Typical sources etc?

I have a background in electrical/electronics so hope I can track it down myself, but I just don't know RV electrical too intimately (yet). I'll bring it in if I can't find the definite source, but thinking:

1) Test on different AC source....could have been the campground electrical reversed

2) Hot water heating element is shorted (I'll see if it heats while only on AC)

3) Neutral to ground shorts.

4) Worn/shorted wiring (pull wiring off all the terminal blocks and test each one for shorts etc.)

Not sure where else to look....thoughts?

Edit: Am considering replacing all the old breakers with GFI+AFCI breakers. Would cost a few bucks, but certainly add protection I think...

Idea...powering up the trailer (and seeing if the skin goes hot again) and then shutting off each breaker one at a time to see if I can track down a shorted circuit.

Grant

Grant
2011 R-Pod 177

mjlrpod

Senior Member

Joined: 27 Sep 2016
Location: Massachusetts
Online Status: Offline
Posts: 1214

Posted: 26 Jun 2020 at 11:22am

A hot skin condition is something I have definitely heard of, but am not really sure what causes it. I think it's a bad ground, but don't really know. I heard that installing an EMS will not allow a hotskin condition and that's partly why I installed one. Please report back what you find.

I copied this link from the pod mods section. One of the admins has a bunch of resources linked in there.

http://www.rpod-owners.com/forum_posts.asp?TID=4748&title=important-check-this-every-time-you-set-up

2017.5 Rp-172
2020 R-pod 195
2015 Frontier sv 4.0L 6cyl
I'll be rpodding

ArthroPod

Newbie

Joined: 10 May 2014
Location: United States
Online Status: Offline
Posts: 16

Posted: 26 Jun 2020 at 12:35pm

I once had this occur and the power source had wires reversed which is first on your list.

177 toad with Ford 150

GlueGuy

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Joined: 15 May 2017
Location: N. California
Online Status: Offline
Posts: 2627

Posted: 26 Jun 2020 at 12:58pm

What you have is probably what's called a "Reverse Polarity Bootleg Ground". A regular outlet tester will show it as "correct", when it's actually the opposite of correct. Very dangerous. It requires some intelligence with a multimeter to figure out.

bp
2017 R-Pod 179 Hood River
2015 Ford F150 SuperCrew 4WD 3.5L Ecoboost

mcarter

podders Helping podders - pHp

Joined: 07 Apr 2016
Location: Greenbrier, TN
Online Status: Offline
Posts: 3419

Posted: 26 Jun 2020 at 1:16pm

If you have never seen this condition before, odds are it is associated with the campsite. Caused by the frame of RV not at same potential as earth around it. The ground connection power cord should keep you within 2/3 volts of campsite potential. If you didn't see any potential increases after going thru the CB test, I would guess that eliminates your reefer, WH and AC. I would report to campsite management and see if you get can get another campsite. If you experience same on another campsite, take the trailer home. It can be fatal if the ground gets wet and you are standing in water and touching the trailer. Once you know it is the trailer, you have several ways to go to include an RV tech, EMS mod, etc.

Mike Carter
2015 178
" I had the right to remain silent, I just didn't have the ability."

Grant177

Groupie

Joined: 15 Mar 2020
Location: Edmonton, AB
Online Status: Offline
Posts: 65

Posted: 26 Jun 2020 at 6:08pm

Unfortunately, as the trailer is new to us this year, I don't really know if this was a pre-existing condition or just due to the site. We only used it once previously while camping and with dry conditions etc, maybe we were just lucky not to get zapped. I did work on it numerous times prior as well with no ill results.

I'll be heading back to it tomorrow, safely plugging it in and doing numerous tests to see what results. Picked up a non-contact voltage sensor today so should be easier for quick testing than my trusty multimeter.

Fun times.....

Grant
2011 R-Pod 177

mcarter

podders Helping podders - pHp

Joined: 07 Apr 2016
Location: Greenbrier, TN
Online Status: Offline
Posts: 3419

Posted: 26 Jun 2020 at 6:49pm

That is a good plan. We all started somewhere. Half the fun. You get it back on a reliable power source and don't see issue, that would be good. I check mine here at house on occasion. I know the trailer is good. I always check when I go to a campsite, so far so good. I was talking to a guy on another forum, who is in a campground established in 1938. I'd check. Just a point, the potential can exist in a dry condition, it becomes dangerous when the ground is wet and a person makes contact to trailer and the ground.

Mike Carter
2015 178
" I had the right to remain silent, I just didn't have the ability."

offgrid

Senior Member

Joined: 23 Jul 2018
Online Status: Offline
Posts: 5290

Posted: 27 Jun 2020 at 5:27am

Well this is getting interesting.

The national electric code requires there to be a bonding conductor connecting the chassis of an RV to the equipment grounding buss in the RV panel board. For the record, this is Article 551.56 (B) in the 2020 Code. If that is connected them you shouldn't have much voltage between earth and the chassis (but it can be more than mcarter's 2/3 volt especially in a RV park where the earth ground at the park service panel might be pretty far away).

I'm practically never plugged into mains power so I've never verified that on my trailer. Well, guess what, I show an open on my ohmmeter between the ground pin on my power inlet and the chassis. If you have this condition it is very easy to develop a high voltage between the chassis and earth ground, in fact typically you will have some voltage roughly midway between 0 and 120V depending on the actual resistance between the chassis and earth vs the chassis and the line voltage in your 120V circuits.

So, I would check that first. Pull the cord and measure the resistance between each of the 3 pins and the frame of the trailer. The ground pin should be low resistance, the other two pins should show open. There should NOT be a connection at the trailer (or a the pedestal) between the neutral and equipment ground conductors. Those should only be connected at the park (or your home) service panel.

My ground pin is open so now I've got to go back and find out why, presumably a terminal somewhere has corrosion on it....could be that's your problem too.

1994 Chinook Concourse
1995 RV6A Experimental Aircraft
2015 Rpod 179 - sold

Grant177

Groupie

Joined: 15 Mar 2020
Location: Edmonton, AB
Online Status: Offline
Posts: 65

Posted: 28 Jun 2020 at 9:16pm

So, after a pretty full day of troubleshooting.....and playing follow the wire, ran into a couple issues.

Could not under any situation detect any hot skin voltage. Nothing. Took every test I could think of. So, was thinking it was maybe the campground power...

Then tried out with the heating element test. Nothing. Could not detect anything so removed it (see picture) and replaced it. Was hoping all would be done after this...

...but as it is with my life...no such luck. Drove me crazy after that point...was getting no power at the element terminal, but there was 120v at the switch.

Taking voltages at so many points I finally figured out behind the black rubber "reset" pad there are two sets of thermostats/high limit switches (or some other protection device).

They look look like this....the propane side is fine...but the AC side is fried. The "wire" shown between the two terminals is cooked in half.

So...another part to order...but at least tracked it down....I think.

So, the "hot skin" problem still not 100% solved, but I can't seem to re-create it...so likely a combination of the water heater element and/or campground power...or both.

Will update when fixed once and for all...

Grant
2011 R-Pod 177

offgrid

Senior Member

Joined: 23 Jul 2018
Online Status: Offline
Posts: 5290

Posted: 29 Jun 2020 at 5:25am

Did you check the resistance between your power inlet ground pin and the chassis? You might still be missing a connection from the chassis to the panel equipment ground buss. If that was intact you shouldn't have developed the voltage from chassis to earth that you did, unless of course that campground's electrical distribution system was faulty.

1994 Chinook Concourse
1995 RV6A Experimental Aircraft
2015 Rpod 179 - sold

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Grant177 Members Profile Send Private Message Find Members Posts Add to Buddy List Groupie Joined: 15 Mar 2020 Location: Edmonton, AB Online Status: Offline Posts: 65	Topic: Tips on Finding Hot Skin Source Posted: 26 Jun 2020 at 9:32am
	OK....so last camping trip, while plugged into a 30A receptacle, I went to tie down a screen tent rope to the trailer as there was some light rain (wet ground) and winds were picking up. I touched the trailer frame I got zapped... Quickly took out the multimeter and was getting about 90v AC from frame to earth (just sticking the mm probe into the dirt). Immediately unplugged the trailer, but did a couple more tests when it was safe to do so and confirmed the frame is hot... An AC plug tester in the trailer outlets showed everything OK (though I don't know if a household outlet tester is ideal for testing a trailer receptacle?). I am going to where I have it parked now and will start testing everything I can find, but wondering if anyone has any good tips where to start etc? Typical sources etc? I have a background in electrical/electronics so hope I can track it down myself, but I just don't know RV electrical too intimately (yet). I'll bring it in if I can't find the definite source, but thinking: 1) Test on different AC source....could have been the campground electrical reversed 2) Hot water heating element is shorted (I'll see if it heats while only on AC) 3) Neutral to ground shorts. 4) Worn/shorted wiring (pull wiring off all the terminal blocks and test each one for shorts etc.) Not sure where else to look....thoughts? Edit: Am considering replacing all the old breakers with GFI+AFCI breakers. Would cost a few bucks, but certainly add protection I think... Idea...powering up the trailer (and seeing if the skin goes hot again) and then shutting off each breaker one at a time to see if I can track down a shorted circuit. Grant
	Grant 2011 R-Pod 177

mjlrpod Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: 27 Sep 2016 Location: Massachusetts Online Status: Offline Posts: 1214	Posted: 26 Jun 2020 at 11:22am
	A hot skin condition is something I have definitely heard of, but am not really sure what causes it. I think it's a bad ground, but don't really know. I heard that installing an EMS will not allow a hotskin condition and that's partly why I installed one. Please report back what you find. I copied this link from the pod mods section. One of the admins has a bunch of resources linked in there. http://www.rpod-owners.com/forum_posts.asp?TID=4748&title=important-check-this-every-time-you-set-up
	2017.5 Rp-172 2020 R-pod 195 2015 Frontier sv 4.0L 6cyl I'll be rpodding

ArthroPod Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 10 May 2014 Location: United States Online Status: Offline Posts: 16	Posted: 26 Jun 2020 at 12:35pm
	I once had this occur and the power source had wires reversed which is first on your list.
	177 toad with Ford 150

GlueGuy Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: 15 May 2017 Location: N. California Online Status: Offline Posts: 2627	Posted: 26 Jun 2020 at 12:58pm
	What you have is probably what's called a "Reverse Polarity Bootleg Ground". A regular outlet tester will show it as "correct", when it's actually the opposite of correct. Very dangerous. It requires some intelligence with a multimeter to figure out.
	bp 2017 R-Pod 179 Hood River 2015 Ford F150 SuperCrew 4WD 3.5L Ecoboost

mcarter Members Profile Send Private Message Find Members Posts Add to Buddy List podders Helping podders - pHp Joined: 07 Apr 2016 Location: Greenbrier, TN Online Status: Offline Posts: 3419	Posted: 26 Jun 2020 at 1:16pm
	If you have never seen this condition before, odds are it is associated with the campsite. Caused by the frame of RV not at same potential as earth around it. The ground connection power cord should keep you within 2/3 volts of campsite potential. If you didn't see any potential increases after going thru the CB test, I would guess that eliminates your reefer, WH and AC. I would report to campsite management and see if you get can get another campsite. If you experience same on another campsite, take the trailer home. It can be fatal if the ground gets wet and you are standing in water and touching the trailer. Once you know it is the trailer, you have several ways to go to include an RV tech, EMS mod, etc.
	Mike Carter 2015 178 " I had the right to remain silent, I just didn't have the ability."

Grant177 Members Profile Send Private Message Find Members Posts Add to Buddy List Groupie Joined: 15 Mar 2020 Location: Edmonton, AB Online Status: Offline Posts: 65	Posted: 26 Jun 2020 at 6:08pm
	Unfortunately, as the trailer is new to us this year, I don't really know if this was a pre-existing condition or just due to the site. We only used it once previously while camping and with dry conditions etc, maybe we were just lucky not to get zapped. I did work on it numerous times prior as well with no ill results. I'll be heading back to it tomorrow, safely plugging it in and doing numerous tests to see what results. Picked up a non-contact voltage sensor today so should be easier for quick testing than my trusty multimeter. Fun times.....
	Grant 2011 R-Pod 177

mcarter Members Profile Send Private Message Find Members Posts Add to Buddy List podders Helping podders - pHp Joined: 07 Apr 2016 Location: Greenbrier, TN Online Status: Offline Posts: 3419	Posted: 26 Jun 2020 at 6:49pm
	That is a good plan. We all started somewhere. Half the fun. You get it back on a reliable power source and don't see issue, that would be good. I check mine here at house on occasion. I know the trailer is good. I always check when I go to a campsite, so far so good. I was talking to a guy on another forum, who is in a campground established in 1938. I'd check. Just a point, the potential can exist in a dry condition, it becomes dangerous when the ground is wet and a person makes contact to trailer and the ground.
	Mike Carter 2015 178 " I had the right to remain silent, I just didn't have the ability."

offgrid Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: 23 Jul 2018 Online Status: Offline Posts: 5290	Posted: 27 Jun 2020 at 5:27am
	Well this is getting interesting. The national electric code requires there to be a bonding conductor connecting the chassis of an RV to the equipment grounding buss in the RV panel board. For the record, this is Article 551.56 (B) in the 2020 Code. If that is connected them you shouldn't have much voltage between earth and the chassis (but it can be more than mcarter's 2/3 volt especially in a RV park where the earth ground at the park service panel might be pretty far away). I'm practically never plugged into mains power so I've never verified that on my trailer. Well, guess what, I show an open on my ohmmeter between the ground pin on my power inlet and the chassis. If you have this condition it is very easy to develop a high voltage between the chassis and earth ground, in fact typically you will have some voltage roughly midway between 0 and 120V depending on the actual resistance between the chassis and earth vs the chassis and the line voltage in your 120V circuits. So, I would check that first. Pull the cord and measure the resistance between each of the 3 pins and the frame of the trailer. The ground pin should be low resistance, the other two pins should show open. There should NOT be a connection at the trailer (or a the pedestal) between the neutral and equipment ground conductors. Those should only be connected at the park (or your home) service panel. My ground pin is open so now I've got to go back and find out why, presumably a terminal somewhere has corrosion on it....could be that's your problem too.
	1994 Chinook Concourse 1995 RV6A Experimental Aircraft 2015 Rpod 179 - sold

Grant177 Members Profile Send Private Message Find Members Posts Add to Buddy List Groupie Joined: 15 Mar 2020 Location: Edmonton, AB Online Status: Offline Posts: 65	Posted: 28 Jun 2020 at 9:16pm
	So, after a pretty full day of troubleshooting.....and playing follow the wire, ran into a couple issues. Could not under any situation detect any hot skin voltage. Nothing. Took every test I could think of. So, was thinking it was maybe the campground power... Then tried out with the heating element test. Nothing. Could not detect anything so removed it (see picture) and replaced it. Was hoping all would be done after this... ...but as it is with my life...no such luck. Drove me crazy after that point...was getting no power at the element terminal, but there was 120v at the switch. Taking voltages at so many points I finally figured out behind the black rubber "reset" pad there are two sets of thermostats/high limit switches (or some other protection device). They look look like this....the propane side is fine...but the AC side is fried. The "wire" shown between the two terminals is cooked in half. So...another part to order...but at least tracked it down....I think. So, the "hot skin" problem still not 100% solved, but I can't seem to re-create it...so likely a combination of the water heater element and/or campground power...or both. Will update when fixed once and for all...
	Grant 2011 R-Pod 177

offgrid Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: 23 Jul 2018 Online Status: Offline Posts: 5290	Posted: 29 Jun 2020 at 5:25am
	Did you check the resistance between your power inlet ground pin and the chassis? You might still be missing a connection from the chassis to the panel equipment ground buss. If that was intact you shouldn't have developed the voltage from chassis to earth that you did, unless of course that campground's electrical distribution system was faulty.
	1994 Chinook Concourse 1995 RV6A Experimental Aircraft 2015 Rpod 179 - sold