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08-14-2014, 09:09 AM
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#1
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Site Team - Lou
Join Date: Oct 2009
Location: South Eastern PA
Posts: 23,269
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Shocked by Frame to Ground
While packing up to come home from the Rally, I got a shock when touching a tire hub and kneeling on the ground. It was not "a lot" but it got my attention.
More of a tickle than a strong shock, I was still concerned.
At our intermediate stop, the shock I got was much stronger when touching any frame part while kneeling on (or touching) the ground.
The Franks was not complaining about this so I assumed (correctly as it turned out) that incoming power was not the problem.
Home, I metered power from the metal to the dirt and got 39 volts AC and 14 volts DC. Scratched my head for a while and decided it had to be a neutral/ground problem and traced it to a bad connection where the Neutral and the Camper Ground were bonded to the frame.
Removed, cleaned and reinstalled the screw/terminals and we are now back in the "No Shock" zone.
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Lou & Freya the wonder dog
2008 GMC Sierra 3000HD Allison Duramax
2019 Flagstaff 8529FL
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08-14-2014, 09:52 PM
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#2
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Senior Member
Join Date: Apr 2013
Location: Louisiana
Posts: 202
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Thanks for the post Herk. The neutral is a current carrying conductor. Bad connection can very well energize the frame and any metal parts attached to it. I have seen that happen in tin mobile homes also.
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doodler
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08-14-2014, 10:01 PM
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#3
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Senior Member
Join Date: Oct 2013
Posts: 1,443
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I worked for the phone company for a few yrs a while back and we had a meter that we were required to check mobile homes with before we did any work. Mobile homes can get energized enough that it can hurt you severely.
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Think about things before you do them make life easier not harder.
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08-14-2014, 10:52 PM
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#4
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Always Learning
Join Date: Nov 2011
Location: Four Corners, FL
Posts: 21,891
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Any chance you took a "before" picture?
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Officially a SOB with a 2022 Jayco Precept 36C
Checkout my site for RVing tips, tricks, and info | Was a Fulltime Family for 5 years, now we're part-timing on long trips
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08-15-2014, 01:04 AM
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#5
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Incheon, S. Korea
Join Date: Jul 2012
Location: Incheon, South Korea
Posts: 1,142
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You mentioned the "No Shock Zone." I take it you're familiar with Mike Sokol?
http://www.noshockzone.org/rv-electrical-safety-part-iv-hot-skin/
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Me, Julie, Lil' Barry, Faith, and OSD Fang
2012 Coachmen Clipper 126 - Don't even have a TV anymore.
I don't know when we'll be able to go camping again...
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08-15-2014, 05:21 AM
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#6
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Senior Member
Join Date: Sep 2012
Location: Virginia
Posts: 9,933
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Thanks for passing the info along knowledge is a very important part of RVing safety. I had forgotten (doing more of that lately) We had the same issue with 1988 Terry a many moons ago.
Last month I had to rescue a camping neighbor that got his arm caught in his awning as he put it away looked painful...........
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08-15-2014, 06:05 AM
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#7
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Site Team - Lou
Join Date: Oct 2009
Location: South Eastern PA
Posts: 23,269
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Quote:
Originally Posted by ependydad
Any chance you took a "before" picture?
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Doug, that WAS a "before" picture!
The corrosion was rust at the threads and under the bolt head.
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Lou & Freya the wonder dog
2008 GMC Sierra 3000HD Allison Duramax
2019 Flagstaff 8529FL
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08-15-2014, 06:09 AM
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#8
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Site Team - Lou
Join Date: Oct 2009
Location: South Eastern PA
Posts: 23,269
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Quote:
Originally Posted by BigBaron
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Excellent article. Will also check for that just in case.
Re-bonding seems to have fixed it, but perhaps the now solid ground is masking my problem. Will let you know.
If the Neutral and Hot were reversed at the campground, the power conditioner should have alerted me with a "red" indicator light though...
Also you would have 120 volts between the Neutral Buss and the "Ground" (green/bare wire) Buss if the Neutral/Hot was switched (Reverse Polarity) at the campground (or at the socket - in the article).
There was less than a volt when measured between those two; yet 39 volts between the frame and the dirt outside.
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Lou & Freya the wonder dog
2008 GMC Sierra 3000HD Allison Duramax
2019 Flagstaff 8529FL
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08-15-2014, 06:26 AM
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#9
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Senior Member
Join Date: Jul 2014
Location: SW Missouri
Posts: 357
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Would this normally be located on the frame close to the converter or near where shore power is connected?
Might be good to check this periodically.
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2014 Ram 2500 4x4 CCSB 6.7L 68RFE
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08-15-2014, 07:16 AM
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#10
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Site Team - Lou
Join Date: Oct 2009
Location: South Eastern PA
Posts: 23,269
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Quote:
Originally Posted by offroad
Would this normally be located on the frame close to the converter or near where shore power is connected?
Might be good to check this periodically.
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It was directly under the converter at the frame.
The green wire went directly from the converter's ground buss to the frame (via a hole in the floor) and the Neutral from the converter's buss went to another Neutral buss screwed to the floor; and then to the frame via the same hole as the green ground wire.
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Lou & Freya the wonder dog
2008 GMC Sierra 3000HD Allison Duramax
2019 Flagstaff 8529FL
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08-15-2014, 07:25 AM
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#11
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Senior Member
Join Date: Sep 2011
Location: Western Iowa
Posts: 703
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Well...after reading that article, I now have two more gadgets to pack in my handy camping tool bag (both of which I already own but never thought to bring along).
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2018 Ford F250
2019 Arctic Wolf F295QSL8
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08-15-2014, 08:11 AM
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#12
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Senior Member
Join Date: Dec 2012
Posts: 7,652
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Just an observation. Looks like the ground point was not burnished (is still painted) and also appears that there is a star washer between terminal lug and ground point (a no-no). For proper bonding there should be no hardware between any stacked terminal lugs and bottom lug at bonding point. Additionally, the area beneath lugs should be burnished to expose bare metal and the J-BOX should also be correctly bonded.
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08-15-2014, 08:50 AM
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#13
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Always Learning
Join Date: Nov 2011
Location: Four Corners, FL
Posts: 21,891
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Quote:
Originally Posted by Herk7769
Doug, that WAS a "before" picture!
The corrosion was rust at the threads and under the bolt head.
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Wow. It "looks" fine from the picture. I wouldn't have guessed.
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Officially a SOB with a 2022 Jayco Precept 36C
Checkout my site for RVing tips, tricks, and info | Was a Fulltime Family for 5 years, now we're part-timing on long trips
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08-15-2014, 08:53 AM
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#14
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Site Team - Lou
Join Date: Oct 2009
Location: South Eastern PA
Posts: 23,269
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Quote:
Originally Posted by bubbles
Just an observation. Looks like the ground point was not burnished (is still painted) and also appears that there is a star washer between terminal lug and ground point (a no-no). For proper bonding there should be no hardware between any stacked terminal lugs and bottom lug at bonding point. Additionally, the area beneath lugs should be burnished to expose bare metal and the J-BOX should also be correctly bonded.
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What is the "J-Box"? "Junction Box"?
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Lou & Freya the wonder dog
2008 GMC Sierra 3000HD Allison Duramax
2019 Flagstaff 8529FL
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08-15-2014, 09:15 AM
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#15
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Site Team - Lou
Join Date: Oct 2009
Location: South Eastern PA
Posts: 23,269
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Just checked all circuits for reverse polarity and all outlets checked "Correct."
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Lou & Freya the wonder dog
2008 GMC Sierra 3000HD Allison Duramax
2019 Flagstaff 8529FL
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08-15-2014, 09:24 AM
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#16
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Senior Member
Join Date: Jul 2013
Location: BoCoMo
Posts: 2,784
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Subscribing.... I was sitting on the ground and installing scissor jacks.... getting a 'tingle' feeling from the frame..... Suggestions on how to find the short?
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Brother Les
2013 Forest River Salem Hemisphere SBT312QBUD
2001 CrewCab F-250 7.3 PowerStroke Diesel
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08-15-2014, 09:27 AM
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#17
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Senior Member
Join Date: Dec 2012
Posts: 7,652
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Sorry for that. Yes junction box. But really meant that if the bonding for ground returns is not directly to the primary return item used (framing, etc.) but rather through any other means (box, tab, etc.) that bare metal to metal contact between the other means and primary return item should still be accomplished. "Floating Grounds" may cause great havoc with electrical circuits.
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08-15-2014, 09:27 AM
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#18
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Member
Join Date: Mar 2012
Location: Southern Louisiana
Posts: 50
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Very interesting thread.
I read an article recently where a little boy was killed by the "hot skin" condition. His dad plugged into the pedestal and the boy touch the door handle to go inside and was electrocuted. I started researching and came across the same No shock Zone website as linked in this thread. It's a very informative read and provides a simple inexpensive solution to mitigate the risk.
I also use a Frank's auto transformer and originally wondered if it offered protection from hot skin. After reading of Herks experience, it sounds like the answer might be maybe. Regardless I purchased a non-contact tester and it officially became a part of my set up routine this past weekend. Is it probable that this will happen? Who knows? But it absolutely is possible. I figured for 20 bucks and 20 seconds it's worth it to reduce any potential hazard. The alternative sucks.
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08-15-2014, 09:40 AM
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#19
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Site Team - Lou
Join Date: Oct 2009
Location: South Eastern PA
Posts: 23,269
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Quote:
Originally Posted by Brother Les
Subscribing.... I was sitting on the ground and installing scissor jacks.... getting a 'tingle' feeling from the frame..... Suggestions on how to find the short?
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Start with the article in Big Baron's post and then go to the ground/Neutral lugs from the converter.
One or the other should fix it.
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Lou & Freya the wonder dog
2008 GMC Sierra 3000HD Allison Duramax
2019 Flagstaff 8529FL
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08-15-2014, 09:44 AM
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#20
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Site Team - Lou
Join Date: Oct 2009
Location: South Eastern PA
Posts: 23,269
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Quote:
Originally Posted by Pirogue
I also use a Frank's auto transformer and originally wondered if it offered protection from hot skin. After reading of Herks experience, it sounds like the answer might be maybe.
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The Franks will alert you to reverse polarity with the red light (Much like every other power monitor - Surge Guard, etc).
However, if the failure is on the "output" side (like a poorly bonded Neutral at the camper's frame), the power monitor will never "see" it.
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Lou & Freya the wonder dog
2008 GMC Sierra 3000HD Allison Duramax
2019 Flagstaff 8529FL
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