I'm Mike Sokol, the author of the hot-skin link posted above. PLEASE don't accept any shocks or tingles from your RVs. At the very least, the OP has an open or high-impedance safety ground connection between the frame of the trailer and the neutral-ground bonding point in the electric service panel. This can occur in a lot of different places, but usual suspects are any dog-bone or pigtail adapters, extension cords with broken ground pints, power receptacles with unconnected grounds, and a poor connection inside your RV's breaker panel where the green ground wire is bonded to the chassis. Note that the white neutral wire is NEVER bonded to the chassis. If your RV is properly safety grounded, you will NEVER feel any kind of shock to earth. I have a very simple test method using a brake light bulb for checking all extension cords, adapters, and chassis bonds for a low-impedance connection that will sustain fault currents. I'll post that later today on
http://www.NoShockZone.orgSecondly, as a previous poster noted, there must be a source of this voltage. And it's perfectly normal for ALL appliances to leak current to their chassis frames. Virtually every microwave, television, phone charger, inverter, and even a slow cooker has a small amount of this leakage and if ungrounded will float up around 40 to 80 volts above earth potential. How much current is leaking determines if you get a tingle, a serious shock, or death by electrocution. Typically, an appliance will leak less than 1 mA of current, but that can quickly change with any damage to the appliance or electronic failure, and certainly water in a junction box can cause all kinds of current leakage. Plus this current leakage is additive, so every additional appliance or electrical gadget you turn on will add a little more leakage current. Even a typical "surge strip" will leak current to ground, and if plugged into an ungrounded receptacle will create a 60 volt chassis potential. Seems crazy, but that's how it all works. Also, NEVER plug your RV into an ungrounded extension cord to check for these leakage currents. However, you can use a clamp-ammeter on the ground wire of the extension cord to check for these leakage currents. And yes, if the additive currents exceed around 5 mA, then your RV will trip a GFCI that's normally on all exterior 20-amp receptacles. That does not mean that the GFCI is wrong, since it's doing exactly what it's supposed to.
Finally, there's one more VERY dangerous mis-wiring condition that can turn ANY RV into a killer. I've identified something I call an RPBG outlet (Reverse Polarity Bootleg Ground) which sometimes happens in pre 1970's building and campground wiring. An RPBG outlet can occur when an older 2-wire outlet was upgraded to a 3-wire grounded one. The electricians were supposed to run a new grounded wire to the outlet box, but many cheated by simply installing a jumper between the ground and neutral screws. That's a violation of code, but not immediately dangerous unless the neutral conductor is opened or corroded. But if the hot (black) and neutral (white) wires were accidentally reversed in the walls somewhere (more common than you might think) then the hot contact will be a 0-volts, while the ground and neutral contacts will be at 120-volts. So anything with a ground plug, such as your RV, will appear to operate normally, but its chassis will be hot-skin electrified to 120-volts with full current (20 or more amps). The really crazy thing is that any 3-light tester, voltmeter or even a professional Ground Impedance Tester won't be able to tell if you have a RPBG and will say that everything is safe, when in fact your RV's chassis is at 120-volts above earth ground. Even the most expensive RV surge/voltage protectors WILL NOT find or disconnect your RV from this RPBG outlet induced hot-skin voltage. The only way to find an RPBG is to measure between your RV and earth ground. By far the easiest and safest way is to use a NCVT (Non Contact Voltage Tester) such as a Fluke VoltAlert (90 to 1000 volt model) to check your RV for a hot-skin condition. See my video at
http://www.youtube.com/watch?v=Y8h64X33aKg where I hot-skin electrify a 40-ft RV. Here's my article about RPBG outlets published by Gary Bunzer (The RV Doctor) at
http://www.rvdoctor.com/2001/07/friends-of-gary-mike.html. And here's my latest article at EC&M (Electrical Construction & Maintenance) Magazine where I describe this problem to electricians and electrical inspectors.
http://ecmweb.com/contractor/failures-outlet-testing-exposed Hard to believe, but until I started writing about this last year, the entire electrical industry appeared to be unaware of how and why these RPBG conditions occur.
These articles and videos have been vetted by my EE contacts around the country, so I'm confident this is how it all works. It only takes 30 volts and 30 mA of current to put your heart into fibrillation, so don't accept ANY shocks from your RV or appliances. Unplug immediately until you can determine the cause of the open grounding and current leakage. You can save your own life as well as the life of a family member or friends.
You may contact me directly at mike@noshockzone.org for any clarification.
Mike Sokol
mike@noshockzone.org
www.noshockzone.org
