# Electrical Shock From Frame



## therink (May 13, 2010)

I am at CG this fine weekend. Was under main slide emptying gray water. I grabbed onto slide mechanism for balance and received an electrical shock (just a tingling light shock). I grabbed my voltage meter, put common probe into the dirt and positive to frame. It measured +/- 8 volts ac. 
Someone suggested maybe a bad ground at the campground 30 amp electrical box. Does anyone know if there is a way to check electrical box ground with volt meter? Thanks


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## Joe/GA (Aug 14, 2009)

This can be a very dangerous condition. It sure sounds like you are missing a ground somewhere. If you are missing a ground, you could have a full 120 volts on the frame. If the ground is wet, it could be deadly. The following WEB site should help you. CLICKY THING I'm guilty of not checking, but I think I should start. You should take a tester or a multimeter to the power pedestal and make sure it is good before plugging in your camper. Also, always turn off the breaker before plugging or unplugging your camper. Let us know what you find.


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## duggy (Mar 17, 2010)

This reminds me of a situation I had about 25 years ago. I was standing on my concrete garage floor, in bare feet, and grabbed my vice. I got somewhat of a shock, although it didn't knock me flat. It turned out I had run one of the lags that held the vice down, into an electrical wire to a plug in the bench. That vice had 110 volts to ground, and had been that way for about a year. It wasn't a problem until I went barefoot.

I'm wondering if there is a short between a wire and the frame of the trailer. Possibly it could be in the wires that move back and forth when the slide is operated. If there was a ground strap to that part of the frame, the short would result in a popped breaker. However, if it's the slide frame, it may not be bonded to the rest of the grounding system.


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## hautevue (Mar 8, 2009)

Slide frame: the slide runs on DC, not AC.

Recheck the voltage reading you got of 8 vac, and reconfirm that it's AC, not DC.

Others are absolutely right--disconnect your shore power, check the supply (home or campground pedestal) for a missing ground.

I suspect that you may have a hot ac wire touching the frame somewhere. If an ac wire is slightly pinched and only a strand or two of the wire or just the edge of a wire, is touching the frame, you could have a slight short to ground that does not trip the breaker.

This is very dangerous and if you can't find it "fer sure", you should get an electrician to help. He'll be experienced in not zapping himself.

Good luck!


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## therink (May 13, 2010)

OK, so I checked the 30amp CG receptacle with meter per instructions provided by JOE/GA. Checks OK. Verified that there is about 5 volts ac running through the frame. Unplugged 30amp cord and checked frame again, 0 volts. I have concluded that I have a 110 v short somewhere. I should be able to isolate problem to a circuit by turning off breakers one by one and test frame voltage. Ill do that next. Drive in rain on the way to the CG the other day. It could be water in one of the electrical boxes under the frame. Ill let you know what I find.
Steve


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## duggy (Mar 17, 2010)

hautevue said:


> Slide frame: the slide runs on DC, not AC.


I agree on most slides. However, I'm not familiar with the layout of the Sydney 329fbh. I wondered if it was a model that had the fridge or entertainment center in a slide. Some trailers do have 110 volts in the slide wiring.


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## hautevue (Mar 8, 2009)

You're right, duggy--if the slide out "room" has a reefer, or some such in it, there will be 120v wiring down below. Never thought of that (shows that I don't have that issue in my TT!).

All I thought of was the slide motor(s) and they are 12vdc.

Thanks for noticing this.


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## Nathan (Jan 2, 2007)

Unplug, remove the power center and you can check that the neutral and ground wires are all connected in the back. Also you could throw one circuit at a time until you find which one stops the voltage. That will at least tell you which leg has the short and you can leave it off for the remainder of the weekend. I too would first look for a 120V line running to a slide. There's a lot of movement there.


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## therink (May 13, 2010)

Update: pulled fuse panel. All connections good. I have reduced the cause of voltage leak to 50amp cable that runs along underside (in belly) from rear inlet receptacle to the breaker panel located in upstairs hallway. I removed a small section of belly chloroplast and located the cable. It just runs loose inside the belly (not secured). My guess is that it may have rubbed on a frame member somewhere. I guess it is time to drop the belly and inspect the entire cable run. Argh.....


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## therink (May 13, 2010)

I forgot to mention. After turning off all rv 110v and main 50amp breakers, I still got a voltage reading on the frame ranging from 2v to 6v ac. 
With breakers all on, I tried another test: I turned on my wife's hairdryer, the frame volage jumps from 2v to 6v when the hair dryer is running, then back to 2 volt when I turn off the dryer. Weird.


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## Nathan (Jan 2, 2007)

Does your ubilical disconnect, or push into the trailer? If it pushes in, then there's an electrical box in the compartment and a great location for shorts as the wire is always getting stressed right there. If it is under the belly and you have access to either end, it might be easier just to run a new wire and leave the old one in place. Just a thought....


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## therink (May 13, 2010)

Nathan said:


> Does your ubilical disconnect, or push into the trailer? If it pushes in, then there's an electrical box in the compartment and a great location for shorts as the wire is always getting stressed right there. If it is under the belly and you have access to either end, it might be easier just to run a new wire and leave the old one in place. Just a thought....


50amp cord attaches on outside. I pulled false panel inside rear bedroom and inspected where the receptacle comes in through wall. Cable runs from receptacle then straight into the floor to belly. No visible j box.


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## CamperAndy (Aug 26, 2004)

The issue will be a loose or corroded ground lug on the frame. Look along the frame near the converter and you will see where they run a ground wire from the common buss to the trailer frame. They use a self tapping bolt to attach the lug which may be loose or corroded.

You can test this by checking for resistance between the common buss behind the converter and a bare spot on the tralier frame.


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## Joe/GA (Aug 14, 2009)

hautevue said:


> Slide frame: the slide runs on DC, not AC.


Some slides have AC power run to them. Mine does so that a receptacle and the dining room light get power. So, it's possible to have a pinched cable there. However, I'm still suspicious of a bad ground connection somewhere. 
Years ago, when I was an Electrician, I had a lady complain about getting shocked when she touched her mobile home if it was or had been raining. I found that the ground to the mobile home was good. I talked to the lady again and found that the buried power cable went right under the metal steps. I dug down to the cable that was not buried deep enough and found that there was a nick in the wire. After properly sealing it, no more shocks. What happened was the ground became hot (120 volts was leaking into the ground), your feet were wet and standing on the metal steps that was also wet. So you were charged with some portion of the 120 volts and then touching a grounded mobile home!


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## therink (May 13, 2010)

Excellent feedback everyone. 
Two things in going to try when I get home and hooked to by 30amp: 
1) run the power cord directly to the power panel, jumping connections and bypassing the power cord that runs length of rig in belly.
2) route a second temporary ground from converter/bus bar to frame.

By doing this, I figure I would be able to determine which is the problem without tearing into the belly. Once the culprit is determined, I will then open that area of the belly to run new 50 amp cable or repair bad ground. From what I could tell, the ground leads run through the floor into the belly where I assume the frame connections are.


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## Dano (Sep 21, 2009)

Are you near aeriel power lines. With such a low volage I would suspect induction. Take your vehicle and park it under a high voltage power line, Stick one lead of your VOM on the bumper and the other stuck in the ground. I have measured 600 plus volts AC. THis issue really beats up old copper phone lines. with voltage induction.


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## therink (May 13, 2010)

Dano said:


> Are you near aeriel power lines. With such a low volage I would suspect induction. Take your vehicle and park it under a high voltage power line, Stick one lead of your VOM on the bumper and the other stuck in the ground. I have measured 600 plus volts AC. THis issue really beats up old copper phone lines. with voltage induction.


My buddy I'm camping with just pointed over to overhead high voltage lines (the major kind) about 200' away. The odd thing is that there are no voltage issues on my buddy's fiver, like mine. One thing is that I'm using a metal tripod and he isn't. Hmmmmmm.....
I will remove the tripod in the am and see if it makes difference. We are heading home tomorrow so I will report what I find when I get home.
You guys rock.
Steve


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## therink (May 13, 2010)

Problem solved.
I went and checked frame voltage on by buddys rig, and guess what? 6 +/- volts. When I checked his voltage earlier, but used his landing gear foot (aluminum) as the contact point. Duh!.
Anyway, you were on the money with the powerline theory. The sad part about this whole ordeal is that I obsessed on this all day and got more than dirty checking everything, in fear that my rig was going to burn up. I can only laugh at myself....Time for bed. Thanks everyone.


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## duggy (Mar 17, 2010)

Wow! I never would have thought of that solution. Glad you got it figured out before you tore the whole trailer apart. You learn something every day!!


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## jozway (Jan 28, 2008)

Dano said:


> Are you near aeriel power lines. With such a low volage I would suspect induction. Take your vehicle and park it under a high voltage power line, Stick one lead of your VOM on the bumper and the other stuck in the ground. I have measured 600 plus volts AC. THis issue really beats up old copper phone lines. with voltage induction.










600 volts is alot. Are you sure that's what you measured? That would easily kill someone with that voltage. Think of it ths way your range is 240 volts ac.


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## CamperAndy (Aug 26, 2004)

jozway said:


> Are you near aeriel power lines. With such a low volage I would suspect induction. Take your vehicle and park it under a high voltage power line, Stick one lead of your VOM on the bumper and the other stuck in the ground. I have measured 600 plus volts AC. THis issue really beats up old copper phone lines. with voltage induction.










600 volts is alot. Are you sure that's what you measured? That would easily kill someone with that voltage. Think of it ths way your range is 240 volts ac.








[/quote]

Volts do not kill, Amps or current do the killing. Think of a Testla coil that generates 10's of thosands of volts and you can touch it to make the arcs dance.


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## therink (May 13, 2010)

Update:
Got home today, parked the rig, plugged into my 30amp, got out the volt meter. Guess what, 0.0 volts on frame. Its incredible what those overhead power lines are capable of. Thanks again for the tips and advice. 
Steve


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## Nathan (Jan 2, 2007)

Glad to hear you have it solved.... I'll also make sure I stay farther from overhead lines too....


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## jozway (Jan 28, 2008)

CamperAndy said:


> Are you near aeriel power lines. With such a low volage I would suspect induction. Take your vehicle and park it under a high voltage power line, Stick one lead of your VOM on the bumper and the other stuck in the ground. I have measured 600 plus volts AC. THis issue really beats up old copper phone lines. with voltage induction.










600 volts is alot. Are you sure that's what you measured? That would easily kill someone with that voltage. Think of it ths way your range is 240 volts ac.








[/quote]

Volts do not kill, Amps or current do the killing. Think of a Testla coil that generates 10's of thosands of volts and you can touch it to make the arcs dance.









[/quote]

I was assuming there were watts involved it would only take a little at that voltage. You are absolutely correct.


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## Dano (Sep 21, 2009)

try it yourself. Squeeze the leads between your thumb and for finger some people will hit 10 plus volts. Some are just plain dead.

Find yourself an older mobile home with tin siding. Siding to wet earth Be carefull electric water heaters like to drop elements that go to ground. trailer is only grounded via the frame not a driven electrode Siding becomes very hot.

Don;t ask me about what you do near a 69,000 volt power line with a 100 watt bulb.

Actual y there are documented cases of people stealing power from the electric grid via induction.


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## BoaterDan (Jul 1, 2005)

Dano said:


> try it yourself. Squeeze the leads between your thumb and for finger some people will hit 10 plus volts. Some are just plain dead.
> 
> Find yourself an older mobile home with tin siding. Siding to wet earth Be carefull electric water heaters like to drop elements that go to ground. trailer is only grounded via the frame not a driven electrode Siding becomes very hot.
> 
> ...


I've heard of the induction theft (from my dad who was a Detroit Edison lineman), but not the light bulb trick. Please tell!


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