Shocking experience
 

Two of my last three travel trailers have had a problem where you can get zapped if you touch anything conductive on the trailer and the ground is wet or you're not wearing shoes.

On my current (no pun intended) trailer I've known about it for some time, and the dog will occasionally let out a yelp if she gets to close when it's plugged into the house. It's even tripped the GFI inside the garage a couple of times.

Well, the other day I was on my hands and knees and reached under the trailer to retrieve something and my forehead touched the frame...OMGOoodness!!! ZAP!! :yikes: Sent me rolling across the lawn, saw stars for a few minutes, gave me a good-sized headache too. Well, that's enough of that. Unplugged it and did some research. Found this informative post among others:

http://www.rv.net/forum/index.cfm/fu...g/1/page/1.cfm

Sounds like a serious issue, even deaths have been reported. I just thought I'd pass along what I found for your information.

I have to remember to bring my multimeter home tonight with me to check some circuits and get to the bottom of it.

Yep common issue...usually the adapter is bad...glad you are OK :)

Update
 

I found another very informative post on the subject here:

http://www.sunlineclub.com/forums/f7...ock-11647.html

I followed the procedure outlined therein and found that I had between 6 & 7 M Ohms between the neutral (white) wire and the ground (green) at the end of the cord, including the adapter. This is apparently enough to trip the shore power GFI.

I started working backwards from there. The adapter checked out OK. Disconnected the green wire from the panel to see if it was the cord, it wasn't. Then I started disconnecting neutrals for each circuit at the header and checking each white wire individually with the ground block. Found the bad circuit: it's the water heater. I left it disconnected and flipped its breaker off, then plugged the shore power back into the house (GFI outlet). Ran the microwave, turned on all the lights, etc. Everything works, & the GFI didn't trip.

Now I just need to figure out where the ground wire and white wire are touching in the water heater circuit.

That poor dog of mine... I guess I got what I deserved huh?

They have a neat little device that they sell most every RV store or hardware store.

http://www.grainger.com/Grainger/WES...234?Pid=search

Yeap, Got one of those I leaved plugged into one of my trailers outlets.

Final update: I chased the problem down to something inside the water heater. I get 6.5 M Ohms across the neutral and ground on the water heater plug. We boondock it, so I've never use the electric water heater not can I imagine ever needing to. I just unplugged the cord from it's outlet and marked it with a tag saying something to the effect of "Don't plug this in until you fix the ground fault issue in this circuit". I'll let the next owner know when I send it down the road next year when its time to upgrade.

I had the same problem, touch the side of the tavel trailor and get shocked, eventually found the electric heating element for the refrigerator was going bad, changed element, no more electrical shock.

Electrical engineer in me speaking. Listen up to save your lives.

A high resistance short between the white (neutral) conductor and the ground conductor should pose no hazard, though it might trip the ground fault interupter.

A combination of excessive resistance (might only be a few ohms) and an open ground, along with the above faults will deliver a shock to the frame of the trailer, usually insulated from ground by the tires.

If the polarity is reversed in the plug or socket between the white (neutral) and the black (hot) wires, then the shock delivered could be fatal. Unfortunately, that wiring error is very common.

There are plug in testers as noted above to check the connections. I would consider them life saving devices. Do not plug in to a circuit that does not test good.

Also check your camper cords. Make sure they are the right gauge, have the right connector on them and wired correctly, and the SAFETY ground circuit is in good shape and low resistance. If the connectors heat up when used, they need to be replaced.

There's a lot of hazardous junk out there. Worst one I've seen is what looked like a 30A tt (120V) extension that came in my used camper. It had a 30 amp 240V plug on one end, and a 115V molded socket on the other end. Both were stamped with name brands. The wire between them was 14 gauge, insulated heavily so it looked like 10 gauge. If I had plugged it in to correctly wired mating devices things would have burned, and maybe someone hurt or killed. Somebody bought this thing and put it in their camper.

Long story short, if your cables are good, and you plug into tested good outlet, then any fault in the trailer will simply trip a breaker as it should, and there will never be a hazard.

To let someone occupy a trailer that is a known shocker is criminal negligence.

http://www.noshockzone.org/rv-electr...0%93-hot-skin/

Mike Sokol, the guy that created that website has a few youtube videos demonstrating the RV hot skin problem. He even does a demo using a full size 5th wheel. :o

An RV/travel trailer does not usually have a ground to neutral bond like a house would. The G-N bond is usually done at the service panel before the branch circuits. This give a direct low impedance path in case of an electrical fault in the branch circuit which should pop the cuircuit breaker and de-energize the circuit.

Campground power pedastals usually don't have a G-N bond either. Multiple G-N bonds create ground loops and create their own problems (noise in audio equipment being the most notable).

That tester that spooler linked earlier in this thread will not detect an RV hot skin condition. Nor will they detect a reverse polarity bootleg ground, another dangerous problem. The only reliable way to detect RV hot skin condition is to use a non contact voltage detector. You hold this tool in your hand and if it lights up (some beep also) around your trailer, then you have a problem.

A friend of mine on his 5th wheel had the main power cord, short where it went into the trailer, 50amp service, things started acting funny then a dead short, almost a fire, be careful, good thing to check when not plugged in. improper grounds, loose or corroded can cause problems also.

That's the worst part. When I got the trailer home about a year ago, I plugged the shore power into an extension cord, then into a GFI outlet (7-year old house, all external outlets are GFI). The GFI immediately tripped. Another of my GFIs went bad last year, so I assumed this one was on its way out too. "Well, I don't have time to mess with it right now". So I plugged the shore power adapter into the extension cord so the ground pin didn't engage, thus reversing the polarity. Been like that up until this week, just like a bomb waiting to go off.

Moral of the story: If it trips your breaker or GFI then it's serious! Me > [dummy] Unplug the shore power until you get it sorted out.

Thanks for your input.

Reversed polarity puts the current on the wrong side of the circuit breaker or fuse. The current must go through the breaker or fuse first before going to the load. A fault on a reverse polarity plug may not trip the breaker if the electricity has an alternate path other than back through to the panel. Very bad news if you are the alternate path.

Even worse is in older buildings where 2 wire (hot - neutral) service was the norm, and only had two prong outlets. If the outlets were ever upgraded to three prong, some electricians would wire the ground pin to the neutral (a big no no according to the NEC), instead of running a new three wire cable (hot - neutral - ground). If the wiring was ever mixed up, then you ended up with a reverse polarity with a hot ground (referred to as a reverse polarity bootleg ground or RPBG). No three light tester or even a multimeter can detect this condition by testing the outlet. The outlet will test normal. Sadly a lot of home inspectors rely on the three light tester since it is quick and simple test. A non contact voltage detector can find this however, since there is more of an electrical field around the outlet than one wired normal. A non contact voltage detector will light up within a few inches of RPBG outlet. A normal outlet will only light up when the tip of the non contact voltage dectector is inserted into the hot prong of the outlet.

Mike Sokol's website that I linked to in my post earlier has a lot of good information on that type of outlet and the problems associated with it.

I'm Mike Sokol, the guy quoted in this thread. Thanks for posting my electrical safety links here. As a few of you noted, a properly grounded RV will never shock you, since those fault currents would be routed to the ground-neutral bonding point back in the service panel, and trip a circuit breaker if there was serious current. So a bad water heater element might provide the current, but your RV must also be ungrounded for it to develop a hot-skin condition.

One other thing I will note since this is a diesel forum is that your block heater is basically a little hot-water heater element in your cooling system. So if it develops a leak in the hermetic seal of the block heater due to corrosion, then your truck can develop a hot-skin condition if its power plug isn't properly grounded. The first sign there's a problem with your heater element is that your truck will trip a GFCI when plugged in. Now don't take this as a random trip, since the GFCI is trying to save your life. I've seen a number of other forums where the block heater tripping the GFCI results in the truck owner just plugging into a non-GFCI outlet, or removes the offending GFCI. DO NOT remove a GFCI that's required by code. It's trying to tell you there's an internal current leakage in your block heater. And if you then plug into an ungrounded outlet, you can be electrocuted (killed) when you touch the door handle to get in your truck.

Please let me know if that's a clear enough explanation, and pass this info on to any other truck or RV forums you belong to.

Mike Sokol
mike@noshockzone.org

Thank you for sharing that Mike :) A great website you have put together as well!

We get threads during the cold weather month about block heater and GFCI issues. Usually the cord is to culprit due to it getting used often and wire chafe in the plug ends and being exposed outdoors. I prevented this issue altogether by mounting Marinco sockets on my bumpers and wired to the block heater. Now my only wear item is the extension cord.

I think the miswired outlets and the reverse bootleg outlets could be very problematic for the boating crowd as well, especially at a marina. I'd hate to think what could happen with an aluminum boat with hot skin, especially around salt water :o.

Actually, salt water is pretty safe to have an aluminum boat with a hot skin, since salt water will instantly "ground" the boat and generally trip any circuit breakers. The real danger is freshwater docks, since an electric gradient field can reach out up to 100 feet from the boat. Anyone swimming into this gradient field will become paralyzed the closer they swim to the dock, eventually losing control of their arms and legs and then drowning. In fact, there's no real sign of electrocution unless someone see them struggling in the water. So the cause of death is listed as drowning, when the real reason was a boat dock or boat with improper grounding and no GFCI breaker. This is called Electric Shock Drowning, and is just now being taken seriously by the marine industry.

I'm now working to develop better ground testing methods around boats and docks. In fact, my RPBG information is being presented at the big boating show in Florida this month. It will be interesting to see how well it's received by the industry. Here's a link to a website on the Electric Shock Drownings. For more information go to : http://qualitymarineservices.net/ and click on the "Safety" button on the left.

Mike Sokol
mike@noshockzone.org