coach tried to kill me -30 VAC to ground

[dave silva]

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

 

[Ken H.]

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 <

> 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
>
>
>
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> GMCnet mailing list
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>

 

[john r. lebetski]

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 not screws lose that could be it.
--
John Lebetski
Woodstock, IL
77 Eleganza II

 

[dave silva]

> 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.

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

1972 Revcon Olds 455, toro drive train. All Stock

 

[john r. lebetski]

Now I see you are saying 30A so check any adaptors as well
--
John Lebetski
Woodstock, IL
77 Eleganza II

 

[RF_Burns]

If it was a pretty good jolt, it had to be more than 30VAC. I worked on 12-48VDC all my life and I don't feel 48VDC. When working on telephone lines,
I don't feel 48VDC (idle line voltage)... however if ringing voltage (90VAC) happens, my eyes open wide!

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.

Another good reason to have GFI protection on your shore power.

--
Bruce Hislop
ON Canada
77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.1 ton front end
http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
My Staff says I never listen to them, or something like that

 

[dave silva]

> Now 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

1972 Revcon Olds 455, toro drive train. All Stock

 

[dave silva]

> If 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

1972 Revcon Olds 455, toro drive train. All Stock

 

[terry1]

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.

 

[Ken B]

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