Help Getting Shocked From RV Steps ??

[SoundGuy]

Originally Posted by wa8yxm

For now, if you do not wish to change sites, and till a technician can get to you drive a long rod into the ground, I have some screwdrivers with like 3 foot long shafts.. And use a good clean jumper cable to "jumper" the chassis to the shaft. This may help.

I really don't recommend driving your own "ground rod" if you're feeling a shock from your RV, and here's why. Hard to believe, but the earth below your feet is really a pretty poor "ground". In fact, a standard 8-ft ground rod next to your house can have up to 100-ohms impedance to "earth" and still be within code. That's because the green safety-ground wire of your RV, which is bonded to your chassis, needs to be bonded (connected to) the entrance service panel's Ground-Neutral-Earth bonding point directly in order to have a sufficiently low impedance fault current path (less than 1 ohm to be code compliant). The job of the ground rod is the help dissipate lightning strikes and help pull your local ground-plane close to earth potential.

While your own local ground rod really won't hurt anything, it will do little or nothing to actually "ground" your RV. If you have a normal appliance leakage from hot-to-chassis (a few milliamps) causing your hot-skin voltage, the a 3-ft screwdriver ground rod in damp/wet soil might help dissipate it to earth-ground. That's because that sort of ground-fault leakage is very high resistance (a few thousand ohms) which forms a voltage divider with the 100-ohm ground-rod and drops the hot-skin voltage by a factor of 10 or more. So your 120 volts of high-resistance hot-skin becomes 12 volts which you can't feel with dry hands. However, if you have a mid or low resistance ground-fault leakage from something like a pin-hole leak in a hot-water heater element (10 to 50 ohms) or insulation scraped from a hot wire (less than 1 ohms), that same voltage divider will only be able to drop the initial 120-volts to 110 or 100 volts. Plus this 100 volt hot-skin potential will have a lot current capability (read shock/electrocution potential). So if you then make contact with any metal part of your RV and the earth-ground at the same time, your body's 1,000 ohm resistance (wet hands and feet) will allow up to 100 mA (milliamps) of current to flow through your body and heart. Just 10 mA of 60-Hz Current is a solid shock (and potentially life threatening if you have a weak heart) and 20 mA will cause involuntary muscle contractions to the point where you can't let go of the energized object. And 30 mA of current (just 30 volts AC if your hands and feet are very wet) for a few seconds is almost a guarantee of ventricular fibrillation (your heart stops pumping blood and just jiggles) and certain death within minutes unless CPR and some sort of AED (Automated External Defibrillator) is used to restore your normal heart rhythm.

Part of the problem is that the word "ground" is mis-used for all sorts of things that really aren't "grounding" at all. For instance, bonding something to the chassis of your RV (the negative terminal of a 12-volt DC appliance) is commonly called "grounding", but if you're driving down the road there's really no earth/ground connection at all. I find this "ground" confusion all the time even with electrical engineers and technicians.

So the key lesson is that you should NEVER feel any kind of sustained shock from ANY appliance or RV. I'm not talking about the little static shock you can receive from a carpet, which is harmless. But if you're standing on the dirt/grass/concrete/roadway and feel any tingle at all while touching your RV or tow vehicle (yes, it does extend to your truck as well) then it's time to unplug from shore power immediately and find the source of the hot-skin voltage.

Two years ago in Muncie, Indiana an 18-year old boy was electrocuted (killed) when he stepped from the wet grass into his family RV late at night which was parked in their back yard and powered by an extension cord running into the garage. The family had been feeling a shock from the RV all week, and had wrapped the RV's door handle with electrical tape as a solution. Of course, the combination of bare feet on wet grass and a metal RV step energized to 120-volts was deadly. I remember this one vividly because it happened within 12 hours of me teaching an RV No-Shockz-Zone seminar in Harrisburg PA for the Sprinter Group. And just the year before I had taught a No-Shock-Zone seminar at Ball State University in Muncie for the their T-Com department. I think that education about shock dangers and what causes them is key to electrical safety, so please NEVER accept feeling any kind of shock from your RV. If you do feel a shock, then unplug from shore power immediately and find the problem. I have written dozens of articles on No Shock Zone that will help you understand electricity and how to measure it.

Let's keep safe out there...

[Libero]

Mike

Another "sound" article (no pun intended but I thought it appropriate). I bookmarked the shockzone site. You demonstrated a wealth of knowledge on that site and obviously a lot more is stored in the grey matter between your ears.

I have been an Aeronautical Engineer since 1959 and spent my entire career in that business wherein safety is a paramount consideration in every technical decision or design.

Even through my post grad training and the myriad of technical courses, seminars and training sessions I have been exposed to, I have not come accross any better lay term articulation of general electrical safety issues that EVERY RVer, home owner and well actually, everyone who knows how to flick a light switch or can screw in a light bulb should be aware of IMHO.

Good show. Keep the fountain of knowledge tap flowing.

[Scottybdivin]

Originally Posted by Retired and Happy

I had this problem on our previous MH, but didn't realize it. When I worked in my power cpmpartment, my forearm would get a shock . It felt like hitting a sharp object, and I thought it was the sharp edge of the compartment. It was ony later when I was having some other electrical work done that it was discovered the transfer switch wes not wired properly and had contributed to this shocking scene. I guess I never noticed when entering the MH because the steps were covered, the sidewalls were fiberglass, and the ground was rarely wet. This was a potentially (pun intended) dangerous situation.

My story is very similar to yours. I was getting the tingle while working on mine. Having grown up in a rural setting around lots of electric fences, I wasn't too concerned. Then when it started raining, the tingle became a ZAP. After reading Mikes articles and speaking to him on the phone, I was horrified at the consequences. The NCVT lit up when it got withing a foot of any part of the RV. Mine also turned out to be a mis-wired transfer switch that the dealer had replaced a couple days after taking delivery of the RV.

[SoundGuy]

Originally Posted by Scottybdivin

My story is very similar to yours. I was getting the tingle while working on mine. Having grown up in a rural setting around lots of electric fences, I wasn't too concerned. Then when it started raining, the tingle became a ZAP. After reading Mikes articles and speaking to him on the phone, I was horrified at the consequences. The NCVT lit up when it got withing a foot of any part of the RV. Mine also turned out to be a mis-wired transfer switch that the dealer had replaced a couple days after taking delivery of the RV.

There's just no excuse for a dealer mis-wiring something as important as an RV transfer switch. Sadly, there's no requirement for any RV manufacturer or technician to test the safety ground for a low-resistance connection to the chassis. They only do a high-pot test which really doesn't confirm the safety ground's ability to carry a ground fault current. My "Safety Ground Current Test" checks the RV's grounding system for its ability to actually carry a fault current to ground.

I've talked to the RVIA and RVDA about this grounding issue several times, but only get the standard BaU (Business as Usual) line. I guess if enough member manufacturers request it, then the RVIA would make it part of the pre-delivery check-out. My second RV Education 101 article next month will cover this in depth. So if you think it's important, please forward the link to your RV dealer and manufacturer and tell them why you think they should read it and begin training their certified technicians how to perform the test..

[SoundGuy]

Originally Posted by Libero

Mike

Another "sound" article (no pun intended but I thought it appropriate). I bookmarked the shockzone site. You demonstrated a wealth of knowledge on that site and obviously a lot more is stored in the grey matter between your ears.

I have been an Aeronautical Engineer since 1959 and spent my entire career in that business wherein safety is a paramount consideration in every technical decision or design.

Even through my post grad training and the myriad of technical courses, seminars and training sessions I have been exposed to, I have not come accross any better lay term articulation of general electrical safety issues that EVERY RVer, home owner and well actually, everyone who knows how to flick a light switch or can screw in a light bulb should be aware of IMHO.

Good show. Keep the fountain of knowledge tap flowing.

Thanks very much. I've been writing magazine articles for the pro-sound and musician industry for 30+ years, so I know just how hard it is to write about technical subjects for non technical people. I'm looking for a government grant so I can expand this electrical safety info for the general public.

[TQ60]

My background is telecom and land mobile communications.

Ground systwms are mission critical.

Mis-leading is vehicle systems where you have 12 volts and ground and not a return.

The protection device is part of a closed series circuit that includes a path back from the load which often is the return or in 240 vac systems complicated.

If the power is leaking to the chassis and the chassis is not connected to the meter safety ground point then the current may not be enough to cause the protection device to function.

There have been people killed while working on remote sites when they have cut a ground system cable to add in additional spurs.

Too much leakage current in that branch from normally functioning switch mode supplies that were being made safe by that path.

They prepped each wire for splicing and due to their boots and knee pads nothing was felt but when they touched a wire from each side of the cut to make the final connection they were killed.

We all were issued clamp meters and required to check for any measurable ac or dc current before a wire is cut then check for voltage before touching any wire.

Ground rod means squat as the actual path result may not cause the protection device to work and in some conditions just make things worse by false sense of security.

And by no means clip to a water pipe as some may be pvc and you could make shocking water due to minimum meral plumbing.

[SoundGuy]

Originally Posted by TQ60

Ground rod means squat as the actual path result may not cause the protection device to work and in some conditions just make things worse by false sense of security.

Exactly right. I get emails all the time from RV owners who claim that a ground rod or even putting their leveling jacks on the dirt will "ground" their RV. That's completely wrong for just the reasons you gave. A ground rod won't draw enough fault current to trip a circuit breaker, and can lull you into a false sense of security. A properly grounded RV can never develop a hot-skin voltage. If an RV's chassis/skin measures more than a few volts above "earth potential" (maybe 2 or 3 volts) then there's a high resistance connection somewhere in the safety ground path back to the service panels G-N-E bonding point. Code calls for less than 1 ohm impedance (just a fancy word for resistance) in the safety ground path, which can be corrupted by loose screws, corroded contacts, or most likely a break in the wiring somewhere such as an extension cord, dogbone adapter, or even a missing chassis bond in the RV's transfer switch.

You should NEVER feel any kind of shock or tingle from any appliance or RV. If you do, then unplug from power and find the source of the voltage.