| coach tried to kill me -30 VAC to ground [message #358564] |
Sun, 13 September 2020 16:17  |
hertfordnc
Messages: 1164
Registered: September 2009
Location: East NC
Karma: 0
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So the GMC is plugged in, AC is blasting. I crawl under to look at something and when my shoulder completes the path to ground from the chrome bumper i get a pretty serious jolt (i sometimes work on household circuits live, this was a serious jolt)
So it meters 30VAC from the bumper to ground.
THis is going though the generator circuit. THis coach has a bayonet plug into the generator. I have a long RV cord with the bayonet female so i was using that. Inside the transfer switch does its job and the GEN light comes on and all the AC stuff is normal.
Dave & Ellen Silva
Hertford, NC
76 Birchaven, 1-ton and other stuff
Currently planning the Great american Road Trip Summer 2021
It's gonna take a lot of Adderall to get this thing right.
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| Re: [GMCnet] coach tried to kill me -30 VAC to ground [message #358568 is a reply to message #358564] |
Sun, 13 September 2020 17:48  |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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Dave,
Are you saying there was no external power source -- no shore cord
connected? Was the water hose, TV cable, or other line connected?
Obviously, I'm trying to find the source of the coach-to-earth potential
difference.
Ken H.
On Sun, Sep 13, 2020 at 5:17 PM dave silva via Gmclist <
gmclist@list.gmcnet.org> wrote:
> So the GMC is plugged in, AC is blasting. I crawl under to look at
> something and when my shoulder completes the path to ground from the chrome
> bumper
> i get a pretty serious jolt (i sometimes work on household circuits live,
> this was a serious jolt)
>
> So it meters 30VAC from the bumper to ground.
>
> THis is going though the generator circuit. THis coach has a bayonet plug
> into the generator. I have a long RV cord with the bayonet female so i was
> using that. Inside the transfer switch does its job and the GEN light
> comes on and all the AC stuff is normal.
>
>
> --
> Dave & Ellen Silva
>
> 1972 Revcon Olds 455, toro drive train. All Stock
>
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
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Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
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| Re: coach tried to kill me -30 VAC to ground [message #358572 is a reply to message #358564] |
Sun, 13 September 2020 19:16 |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
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You say in first sentence “coach is plugged in” so that means somewhere you have a broken or high resistance ground. Could be the coach or at the receptacle it is plugged into. Ground lug could be loose or pulled out in coach AC panel, 6/4 shore cord could be fatigued at some point, (look for lumps) or the U ground pin at the molded male end could be broken internally (grab it at pull straight out, if it gives it was shot)
Or the house end could be the problem. If the 14-50R is getting it’s ground via conduit and screws lose that could be it.
John Lebetski
Woodstock, IL
77 Eleganza II
[Updated on: Sun, 13 September 2020 19:17] Report message to a moderator |
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| Re: [GMCnet] coach tried to kill me -30 VAC to ground [message #358573 is a reply to message #358568] |
Sun, 13 September 2020 19:17 |
hertfordnc
Messages: 1164
Registered: September 2009
Location: East NC
Karma: 0
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Ken Henderson wrote on Sun, 13 September 2020 17:48Dave,
Are you saying there was no external power source -- no shore cord
connected? Was the water hose, TV cable, or other line connected?
Obviously, I'm trying to find the source of the coach-to-earth potential
difference.
No, it was very definitely plugged in to my dedicated 30 amp outlet.
What's different is that this coach has a male plug in the generator compartment to plug in to the generator. So instead of using the regular AC cord i used the plug in the generator space instead.
THere is a transfer switch so the coach does not know the difference.
I know about 'hot skin" and ground shorts in RV but't never gotten a jolt like this and a lot of the wiring is fairly recent.
Dave & Ellen Silva
Hertford, NC
76 Birchaven, 1-ton and other stuff
Currently planning the Great american Road Trip Summer 2021
It's gonna take a lot of Adderall to get this thing right.
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| Re: coach tried to kill me -30 VAC to ground [message #358578 is a reply to message #358574] |
Sun, 13 September 2020 20:49 |
hertfordnc
Messages: 1164
Registered: September 2009
Location: East NC
Karma: 0
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JohnL455 wrote on Sun, 13 September 2020 19:19Now I see you are saying 30A so check any adaptors as well
No adapters- it's a dedicated connection. Not technically 30AMPS I put a 30AMP female on a dedicated breaker in my garage
Dave & Ellen Silva
Hertford, NC
76 Birchaven, 1-ton and other stuff
Currently planning the Great american Road Trip Summer 2021
It's gonna take a lot of Adderall to get this thing right.
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| Re: coach tried to kill me -30 VAC to ground [message #358579 is a reply to message #358576] |
Sun, 13 September 2020 20:54 |
hertfordnc
Messages: 1164
Registered: September 2009
Location: East NC
Karma: 0
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RF_Burns wrote on Sun, 13 September 2020 20:22If it was a pretty good jolt, it had to be more than 30VAC.
I'm wondering if the water heater element is faulty, along with the body ground to shore line is faulty. The element has a low resistance to the element case (ground) when then passed through you to ground.
Yes, the 30 volts puzzled me but isn't it a function of surface area? I get 30V with a meter lead in the chrome and the other one literally stuck in the dirt.
So when i was laying in the damp grass and my shoulder made a large contact with the chrome that's when it became unpleasant.
Dave & Ellen Silva
Hertford, NC
76 Birchaven, 1-ton and other stuff
Currently planning the Great american Road Trip Summer 2021
It's gonna take a lot of Adderall to get this thing right.
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| Re: coach tried to kill me -30 VAC to ground [message #358586 is a reply to message #358579] |
Sun, 13 September 2020 23:45 |
Bullitthead
Messages: 1411
Registered: November 2013
Karma: 5
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Seconding Bruce on the water heater element, and check the wiring when you check the element, mine was wired wrong (ground and neutral swapped)and it took a lot of diagnosis and disassembly to find that simple error leftover from the P.O..
Terry Kelpien
ASE Master Technician
73 Glacier 260
Smithfield, Va.
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| Re: coach tried to kill me -30 VAC to ground [message #358589 is a reply to message #358564] |
Mon, 14 September 2020 01:03 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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Ignore all of the other things to look at and FIRST follow the integrity of the Green wire ground between the body of the coach and a good earth ground (probably at the power receiptical). It is there to prevent you from getting shocked no matter what else is wrong. Also check the ground at the 30amp receiptical. Fix that FIRST.
Then go fix whatever else you find wrong with the coach electrical.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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