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Old 08-03-2015, 12:34 PM   #1
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I get shocked when touching RV

Mike Sokol has been offering our membership much guidance in the root causes of shocks you may feel when touching metal parts of your RV. This can be a serious and dangerous situation. Mike and the site team would like for you to read the following well-explained post copied over from another thread.... which also explains ways to test for 'hot skin/chassis' to make sure you don't get shocked. We are also making this a sticky in the electrical section for future reference.

Quote:
Originally Posted by DirtSquirt View Post
I replaced the valve on my black water flush out system today and noticed that when I touched any metal part of the frame of my trailer, I could feel an electrical current running through it! Not enough to really shock me, but certainly enough to cause some discomfort. It doesn't matter where on the frame I touch either, it feels the same. What is going on? I have a 2010 Rockwood Roo 23 RS.

Quote:
Originally Posted by jmsokol View Post
This is Mike Sokol from the no~Shock~Zone and I just received a private message from the forum moderator that I was needed here, sort of like the Batman Signal, I guess....

OK, let's get to the bottom of this quickly, since this is a simple thing. But first, let me detail what is is NOT!!!

It's NOT reversed or flipped battery cables. And you certainly don't want to be swapping battery cables at any time since that really DOES reverse polarity and could easily destroy electronics such as your inverters, televisions, stereo systems, etc... That's because a battery has a positive and a negative pole, so reversing the cables actually reverses the polarity, and electronics are VERY sensitive to polarity reversal and can be destroyed by in in a few milliseconds (a millisecond is 1/1000 of a second).

It's NOT reversed polarity on the AC shore power plug, unless something else is miswired at the same time. That's loosely defined as the Hot and Neutral wires being swapped or "reversed" in the extension cord or outlet. But the White Neutral wire is supposed to be isolated from the frame/skin of your RV according to the NEC and RVIA build codes. If you've accidentally bonded (connected) the Neutral and Chassis Ground together, then it's possible that a Reversed Polarity Outlet could energize the RV chassis/skin, but if the ground wires is intact it should trip the circuit breaker immediately.

It's definitely some sort of compromised EGC (Equipment Grounding Conductor) more commonly called a safety ground, or simply "ground" by most consumers. This "ground" is supposed to drain away any small ground fault currents and trip a circuit breaker for any large ground fault currents.

By definition, a ground fault current is any sort of leakage between the incoming hot wires and the chassis of an appliance or your RV itself. There will ALWAYS be some ground fault current available in ANYTHING plugged into a power outlet, but it's normally very small, typically less than 1 mA (1 milliamp or 1/1000 of an ampere). Most of the time there will be a balancing act between the hot and neutral leakage impedance which the open ground hot-skin voltage biasing to around 1/2 of the line voltage. So if your EGC (ground) wire is compromised without anything else being wrong in your RV, you'll often measure 40 to 80 volts between the RV frame and a screwdriver stuck in the earth. While this sort of low-current ground fault may not be immediately deadly, you still need to take it seriously since it can turn into a high current ground fault in a heartbeat, and there will be nothing to stop it from killing you or a loved one.

OK, now let's consider what can compromise your RV's grounding system. There needs to be a solid connection between the frame/chassis of your RV all the way back to the electrical service panel feeding your home or the campground. So everywhere there's a connection, it's possible for a failure to occur. So that means that it could be caused a broken or loose or corroded connection in your shore power cable, extension cord, dog-bone adapter, pedestal outlet, or even the AC power feeding the pedestal or outlet itself. I've seen loose grounding screws inside of the RV's circuit breaker box cause this, and even a broken ground screw on the back of the RV's shore power jack on the side of vehicle. To be code compliant, this EGC (ground) needs to have less than 1 ohm impedance back to the service panel's G-N-E bonding point.

Also, a ground rod connected to the frame of your RV does NOT "ground" your RV. Lot's of reasons for this, but an earthed ground rod can often measure up to 100 ohms to the earth, so while it might drain away a low-current ground fault, it certainly CAN'T drain away a high-current ground fault. That can be caused by a screw being driven though a wire in the wall, or insulation worn through by rubbing on the frame, or even a failed transformer in your microwave oven. As a side note, jacks on the ground do nothing to "ground" your RV, so don't get me started on that subject.

Finally, there's one really dangerous outlet mis-wiring condition I sometimes find in old garages and church outlets. I call it an RPBG (Reverse Polarity Bootleg Ground) and it can't be detected by any standard tests including 3-outlet testers or even metering between H-N, H-G and N-G. You must have an external reference to earth to find it. See my article on it at Failures in Outlet Testing Exposed | Contractor content from Electrical Construction & Maintenance (EC&M) Magazine and my video on how you can use a NCVT (Non Contact Voltage Tester) to easily find a hot-skin condition at So, please take any felt shocks as a sign that something is seriously wrong with your RV's ground system, which could be anywhere from the outlet itself, dog-bone adapter, extension cord, shore power cord, or even the ground bonding point inside your RV itself. I get all the police and inspector reports whenever someone is electrocuted (killed) by an RV or guitar on stage, and most every instance was preceded by someone noticing they were feeling a shock for a few days or even weeks. Modern code requires that RVs and appliances are designed so that you NEVER feel a shock. If you do, then the grounding system has failed. It's as simple as that.

Also, at the risk of self promoting, I think that all of you, especially the ones who are giving out incorrect electrical advice, need to get and read a copy of my book - No~Shock~Zone RV Electrical Safety. This is a must-read before doing any electrical work on your RV, and will certainly give you enough information to discuss electrical problems with a trained technician or licensed electrician.

ATTN MODERATOR - Feel free to delete the book info above if that violates forum self-promotion policy. But I think that everyone who plugs an RV into an electrical outlet needs to understand the basics of electricity for their own safety.

Let's play safe out there...

Mike Sokol
No Shock Zone
Part 2 from same thread:

Quote:
Originally Posted by jmsokol View Post
You are correct. I hate the word "polarity" when referring to AC power. That's because an AC outlet actually reverses its own polarity 120 times per second for 60 Hz power in the US (it's 50 Hz in much of Europe). But the RV industry uses Reversed Polarity to describe what's actually reversed Hot and Neutral wiring. I think that's because in the 40's and 50's there was something called a non-grounded "polarized plug" on radios and home appliances. And those early appliances lacked input transformers, which bonded the incoming neutral wire directly to the chassis. So if the "polarized plug" was flipped, reversing its "polarity", then the radio chassis was connected directly to the hot wire, which could be lethal.

That's why all modern appliances have some sort of power transformer to isolate their own chassis from the power line. The exception is double insulated power tools and things like hair dryers with GFCI plugs. So with all modern appliances and RVs, it really doesn't matter if the hot and neutral wires are reversed. There are tons of old wives tales that swapped H-N lines somehow burns up on-off switches, or causes an appliance to use more electricity, or hum, or whatever. But that's all incorrect information. The REAL danger is that troubleshooting a system with the neutral wire energized to 120-volts can be deadly to the technician doing the testing.

So why should you care if your RV outlet shows reversed polarity? Well, if you have a second miswiring condition in your RV, specifically an internal Ground-Neutral Bond, it's possible for a reversed H-N outlet to create a hot skin condition. Also, it shows that whoever wired the electrical outlet doesn't know what they're doing and could have made other mistakes. So don't accept reversed Hot-Neutral outlets on a pedestal since it's an obvious mistake that should be corrected.

One of the things I've pitched to the RVIA and various inspection agencies is the idea of a testing RV pedestals for proper grounding and "polarity" yearly or maybe every other year. And I think they should also be retested anytime there's been a repair done on a pedestal. But it's slow going since nobody wants to spend money, even if it is for safety.

BTW: I don't like the term "RV hot-skin" either, since it's really a hot-chassis condition that also spreads to the RV "skin". So a hot-skin condition creates voltage not only on the "skin", but also on the RV's wheels, trailer hitch, the tow vehicle, door handles, metal steps, etc... That's why an RV hot skin is so dangerous.

Thanks very much.

Mike Sokol
No Shock Zone
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Old 08-23-2015, 11:25 AM   #2
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Great advice. I had the same issues and tried everything. I finally changed my adaptor plug and realized there was no third grounding prong. The new adapter solved the issue.
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Old 09-01-2015, 10:45 PM   #3
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Had something similar happen to one of our well site trailers in West Texas. When hooked to power, it would bite your hand when you grabbed the door knob. It was pulled out of the field immediately. We sent it in for overhaul and discovered that one of the electric lines had been nicked by a drill during initial build and a lag screw that helped mount the box to the frame was touching the nick. It was an accident and they do happen. You should return the trailer to the dealer or take it to trailer service shop.
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Old 09-02-2015, 12:10 PM   #4
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I had this problem one time and it was eventually traced to the electric heating element in my water heater.
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Old 12-11-2015, 07:31 AM   #5
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Ditto on the water heater element. I've seen where the element heated in an empty water tank. Due to the heat the element melted touching the tank. When the door handle or any metal part of the rv was touched, zap.


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Old 02-14-2016, 12:34 PM   #6
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I get shocked when touching RV

Right after watching Mike's great video, I ordered one of these:

Klein Tools NCVT-2 Dual Range Non-Contact Voltage Tester https://www.amazon.com/dp/B004FXJOQO..._HJlWwbA73XHZB

If you buy one, be sure to check the voltage range. This model covers 12-48V and 481000V and works in single or dual voltage range.

Once you have it, it's interesting to find all the unseen electrical fields, even around your house, such as 2" away from a lamp bulb base. (These are normal.)

Its most important use seems to be to check the RV frame after plugging in to shore power. Other than that, it can quickly help find leaks and also identify live vs. dead lines for troubleshooting malfunctions.


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Old 06-10-2016, 07:53 PM   #7
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I'm having a similar issue and I suspect it is the heating element in my water heater. If I turn the circuit breaker off to the hot water heater, the problem goes away. Tonight, I went to drain my fresh water tank and the circuit breaker for the water heater was on, and I felt an electrical current in the water! After reading this thread, I'm convinced it's the heating element.
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Old 06-10-2016, 08:15 PM   #8
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If you turn on the electric element in the WH without the tank being full, it will destroy the heating element and can cause this symptom ( hot chassis). It should be easy to diagnose as the WH will not heat on electric only. It only takes seconds in an empty tank to to damage the element.
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Old 06-16-2016, 10:45 PM   #9
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Found shock problem

After exhausting everthing in my arsenal i found the problem. I started by using my circuit tester to see if the coach was skin hot with voltage. You can get one at harbor freight 5 bucks turn it on and touch a wire or rv and if voltage is present it will beep. I checked rv and it was hot. Then checked my cable and adapters to make sure the ground was isolated they were good. Next i used my plug in tester and it was telling me my hot and neutral wires were swapped. What!!!!! I tested every receptical in my garage they all were reverse according to the testor. I then connected a long extension cord to house an plugged in rv no stray voltage that exonerated the rv. Now i had to find the problem at garage. Being this was happening when rv was plugged into a 30 amp receptacle on outside of garage i started there i check voltage at 30 plug everything red fine ground , white, and hot ok now i was puzzeled, i removed plug and inspected wires they were in the right places how could they be crossed , white and black? I looke at breaker and decided to remove wire and what i found was the hot wire was rubbed almost all the way thru insulation to ground , this occured from plugging in and taking out over and over time if it had gone all the way thru it would have blew the breaker but did not. Once new wire was run plug put back together i tested all plugs in garage they were now right and rv plugged in was no longer hot success but it tokk all day, hope this helps someone.
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