RV Electrical Safety: Part IV – Hot Skin

Aug 25th, 2010 | By | Category: RV Safety
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The No~Shock~Zone: Part IV – Hot Skin

Understanding and Preventing RV Electrical Damage

Copyright Mike Sokol 2010 – All Rights Reserved

If you’ve read the survey we did July 2010 in www.RVtravel.com, you know that 21% of RV owners who responded have been shocked by their vehicle. Review the 21% report at http://www.noshockzone.org/15/.  What follows is #4 in a 12-part series about basic electricity for RV users and how to protect yourself and your family from shocks and possible electrocution.

This series of articles is provided as a helpful educational assist in your RV travels, and is not intended to have you circumvent an electrician. The author and the HOW-TO Sound Workshops will not be held liable or responsible for any injury resulting from reader error or misuse of the information contained in these articles. If you feel you have a dangerous electrical condition in your RV or at a campground, make sure to contact a qualified, licensed electrician.

The Big Picture

If you’ve been diligently reading this series, you should at this juncture understand the basic concepts of what voltage is, how to read it with a meter and how to check the polarity of a campsite power outlet. If not, then go back and review parts I, II and III on RV electrical safety.

But why is this concept of voltage and polarity so important? Well, one of the greatest dangers of RVing, perhaps second only to a fire (which is really terrifying) is getting shocked and possibly electrocuted when touching the skin of your RV. And while some campers may have been injured by a bare wire on an extension cord or while poking their fingers in a power panel without proper precautions, the majority of RV shocks come when you least expect them, from the skin of your RV while simply opening the door.

Hot Skin

An RV Hot-Skin condition occurs when the frame of the vehicle is no longer at the same voltage potential as the earth around it. This is usually due to an improper power plug connection at a campsite or garage AC outlet. Now to be honest, I think the majority of campgrounds have properly wired and maintained power pedestals, but certainly there are instances where a campsite has outlets with reversed polarity or without proper grounding at all. But I’ve seen enough “rewiring” jobs to know that RV owners are also to blame for improper wiring of their own extension cords and 30-amp adapters.

The scenario could go something like this: You plug your RV plug into a loose or worn campsite power outlet. Everything seems fine until you crank up your air conditioner and turn on your coffee maker. That’s when you notice the smell of burning plastic and find that the male plug on your RV extension cord has melted down due to all that current going through a loose connection. Rather than throw that expensive extension cord away, you go to your local big box store and buy a new power plug. However, when you take the wires off of the old plug there’s no diagram to show you how to connect the new plug properly. If you guess right while putting on a new plug, then all is well. If you guess wrong, then you’ve reversed the polarity of your incoming AC power. After that it just takes the right combination of circumstances such as a rainstorm to wet the ground in front of your RV, and you touching the screen door with a damp hand while standing outside. That’s when you can get shocked or even electrocuted. The severity of the shock can vary from a mild tingle to stopping your heart, depending on how wet you and the ground are and the voltage of your RV skin. But make no mistake, rather than the 30 or 40 volts of a high-resistance tingle, it’s possible to have the skin of your RV go to 120 volts with full current of the campsite pedestal with 20, 30 or even 50 amps available.

Insulation

 

The reason we don’t notice this Hot-Skin condition until it’s too late is that an RV is basically a big metal frame sitting on rubber tires. And those tires act as electrical insulators just like the rubber surrounding the metal wire of your extension cord. That means that the skin of your RV can be electrically charged with 30, 60 or even 120 Volts with no visual indication of the problem until you complete the connection to the earth with your hand. Then because your own body provides a low resistance path to earth (remember the pipes between the water tanks in Part I of this series), current will flow through you to the ground. How much current is really the subject of another article, but if your hands and feet are wet your body becomes a 1,000-Ohm resistor connected from your hand on the doorknob to your feet on the ground. This will allow over 100 mA (milliamperes) of electrical current to flow through your heart. Tests have shown that as little as 10 mA to 20 mA of a 60-Hz current (what comes out of your electrical outlet) can cause your heart to go into fibrillation (essentially a heart attack). So you can easily get 10 times the current needed to kill yourself from a 120-volt outlet. Note that 100 milliamps of current isn’t enough to trip a standard 20- or 30-amp circuit breaker, but it’s supposed to trip a GFCI (Ground Fault Circuit Interrupt) as long as it’s been properly connected. But don’t risk your life on untested technology — check for Hot-Skin conditions before you get shocked.

Making a list, checking it twice….

 What follows are two ways to determine if the skin of your RV has been electrified. One method involves using a voltmeter just like we learned about in Part II of this series, while the second method uses a non-contact AC tester like you see electricians use to check for live outlets. Both methods are described below. But be aware that even if you tested your RV when you made camp and found it safe from a Hot Skin condition, that could change at any time if something happens to the campsite power after you’ve plugged in. If you feel even the slightest tingle from your RV, that’s the time to shut off the circuit breaker from the campsite power and get an electrician to double-check the outlet ground and polarity. Don’t bet your life on a faulty connection.

Using a Meter

After you’ve tested the campsite outlet for proper polarity (Part III of this series), powered off the circuit breaker and connected your RV power plug, now is the time to turn the circuit breaker back on and confirm that your RV is safe from a Hot-Skin voltage.

To use a standard digital voltmeter such as the one we learned about in Part II of this series, you’ll need to set it to measure AC voltage. Note that since a Hot-Skin condition will typically be less than 120 volts, the 200 volt or 750 volt AC setting [as pictured] will be fine.

Just like before, plug the black probe into the black COM connection on the meter and the red probe into the RED VOLTS connection on the meter. Remember, never plug into the 10 Amp connection, and never set the meter dial to amps or ohms. That’s for advanced testing only, and you’ll only blow out the meter’s fuse if you try to test for voltage that way.

 

 

 

Ready… Set… Test….

If you’re close enough to any metal going into the earth, such as the exterior of the pedestal power box or a metal water pipe, poke it firmly with the sharp tip of the black probe. You’ll need to punch through any rust or paint, so an exterior bolt or machine screw is usually a good choice. Now without touching the body of your RV with your hand poke the skin of your RV with the sharp tip of the red probe. Again, this needs to make connection to the metal skin of your RV, so if you want to avoid making little holes in your paint job pick a spot like the trailer hitch or a chrome door knob.

Next, while both probes are making contact you should read very close to 0 (Zero) volts. The National Electrical Code allows up to 2 volts on the ground, so 1 to 2 volts is safe. If, however, you read 10 volts, 50 volts or 120 volts, that’s the time to back away from the RV, turn off the circuit breaker, pull the power plug and immediately get the campsite electrician to find out what’s wrong. If he tells you that 50 volts on the skin of your RV is fine, demand your money back, break camp and get out of there. Do not let your family or pets enter an RV with a Hot Skin condition.  Also, it’s a good idea to alert your local RV association that a campground has a dangerous power condition. That way you help the next RVer, too.

Using a Non-Contact Tester

While a digital voltmeter is the gold standard method for testing Hot Skin conditions, it must be used exactly right or it can give you a false sense of security. Therefore, perhaps the easiest and best way to check for an RV Hot Skin is by using a $30 non-contact AC tester such as a Fluke VoltAlert. These testers look like a fat pen with a plastic tip and are available at hardware stores such as Sears or Lowes. Most have a blinking light and beeper that makes noise when the tip is held near an energized circuit. How do I know these things work? Well, I built a Hot Skin simulator that can energize the body of an RV with any voltage from zero to 120 volts at the twist of a dial. I’ve energized everything from a microphone to an Airstream to find the best Hot-Skin testing methods. Yes, it’s a bit Frankenstein, but this gear allows me to see how well the various test methods work. And the Fluke VoltAlert seems to work very well for Hot-Skin conditions as low as 40 volts.

To test for an RV Hot Skin just turn on the non-contact tester by pushing the power button quickly, which will begin to blink once every few seconds to show you it’s on. Then confirm the tester is working properly by poking it into a hot blade of the power outlet on the pedestal. It should beep at you and blink if all is well. Now, gripping the tester firmly in one hand while standing on the ground, move the plastic tip until it’s touching anything metal around your RV. This could be an aluminum screen door, the exterior of an Airstream or the steel of the trailer hitch. With a non-contact tester you do not have to punch through the layer of paint, rust or plastic. If your RV has more than 40 volts on the skin, the VoltAltert will light up and start beeping at you, even from an inch or more away from the surface of the RV.

Caveats

Now, here are a couple of warnings about using non-contact testers to check for Hot-Skin conditions. 1) These testers need to have your hand wrapped around them to sense the earth ground; so if you hold them with just the tips of your fingers it’s possible to get a false-safe reading. 2) Non-contact testers need your feet to be near the ground to know the actual earth potential, so if you’re standing on a fiberglass ladder they won’t read properly. Additionally, since non-contact testers are looking for the voltage difference between the your hand and the plastic tip of the probe, if you’re standing inside an RV with a Hot Skin and you test your galley sink, they won’t indicate trouble when indeed there is. Therefore, always grip the non-contact tester firmly in your hand while standing on the ground outside your RV. And if your vehicle has as little as 40 volts of Hot Skin potential, the tester should alert you of the danger even without physically touching your RV. You can just slip your VoltAlert pen in your pocket and use it to quickly test any RV in the campground you might be visiting. It only takes a few seconds to test for a Hot-Skin problem this way, and you may save another RV owner’s life.

Outlets Re-visited

Since these non-contact testers are designed to check outlets for electrical power, they’re also a great way to confirm outlet polarity. If you remember what a typical AC outlet looks like, you can poke the VoltAlert into the tall neutral slot (no blink or beep), then the ground hole (no blink or beep) and finally the shorter hot slot (should blink and beep). It won’t tell you the exact voltage of the outlet like a voltmeter, but it will confirm if the polarity is correct and tell you if the ground connection has been floated and electrified by another RV with a short in its own wiring. This is pretty cheap insurance since you can never be too safe around electricity.

Quick Tips

  • Do the Hot-Skin test after you’ve checked campsite outlet polarity and voltages with a volt meter.
  • Perform a Hot-Skin test every time you plug into a new campsite or home power outlet.
  • If you ever feel the slightest tingle or shock from your RV, avoid all contact, shut off the AC power at the pedestal, and get professional help to determine the cause of the shock.
  • Even if you’ve stopped getting shocked from your RV because the ground is dry, the Hot-Skin problem has not fixed itself.
  • Be sure to properly maintain your RV electrical system and test all RV interior outlets for proper polarity and grounding.

Future Shock

Part V of this series will cover amperage and ways to calculate how much your RV needs BEFORE you plug into a power pedestal, so stay tuned.

Feedback

After you’ve read this article at www.RVtravel.com, take a trip over to www.NoShockZone.org and send us your  comments and suggestions. We love to know how we’re doing with this important project.

Mike Sokol is the chief instructor for the HOW-TO Sound Workshops (www.howtosound.com) and the HOW-TO Church Sound Workshops. He is also an electrical and professional sound expert with 40 years in the industry. Visit www.NoShockZone.org for more electrical safety tips for both RVers and musicians. Contact him at mike@noshockzone.org.

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29 Comments to “RV Electrical Safety: Part IV – Hot Skin”

  1. Proto says:

    Another great article, This information has always been out there but you have put it together in one place so that we can not only have the information but are able to do something with it.
    Great job

  2. Alan M Fisher says:

    Thank you for such logical and understandable explanations of electricity and electrical safety. Having taken college level physics many years ago, much of that information has “faded” until now. You have “recharged” my intellectual batteries, and for that blessing, I thank you. I have passed this information to many others. These articles are real “gems”. amf

  3. Andy Brown says:

    Enjoying your series on RV electrical safety. One point on ‘sitting on rubber tires’ inferring insulated from ground. Remember years back gasoline trucks had a static chain to ‘ground’ the static buildup from sloshing gasoline. Note that you no longer see them (for many years). The reason is modern synthetic rubber tires are not as good an insulator as was real rubber. So trucks and RVs are fairly well grounded, depending, of course, on the ground upon which it sits. This can allow ground currents up into RV from earth. Might comment on ground currents in your writing. Thank you for your informative articles. I, as a radio amateur am familiar with most things electrical , but can always use any knowledge that might help keep me alive.

    Thank you again, Andy, n6ijf

    • Mike Sokol says:

      While I think you’re correct about modern tires being more conductive than old rubber tires, I’m pretty sure that there’s so little leakage to ground through modern tire that you wouldn’t notice if your chassis is sitting at 120 volts above ground. I’ll do a few measurements on my Sprinter this week, but I’m guessing it will be in the tens of thousands of ohms to ground. Now that would certainly be enough conductivity to drain off any static charges from driving, but it’s surely not going to draw enough current to trip a 20-amp breaker, and I suspect it won’t even be enough leakage current to trip a GFCI breaker. But I’ll investigate all the circuit paths and leakage levels and see what the actual ground path currents would be. It will be fun to electrify my Sprinter up to 120 Volts and see how much actual current flows to ground through the tires. I’ll take pictures and report back later.

  4. Errol Littleton says:

    Thank you for your excellent articles. We are new to RVing and welcome all the help we can get. We have a Jay Feather with aluminum frame and fiberglass body. Where would you place the second probe instead of the side of the trailer since it is not metal?
    Thanks again, Errol

    • Mike Sokol says:

      The trailer hitch or a lug-nut on a tire is a good place to test for hot-skin voltage. It’s really the trailer frame that’s energized and the RV skin just goes along with that same voltage.

  5. […] his fourth installment, Sokol explains RV Hot-Skin conditions. So what exactly is a hot-skin condition? Sokol says this […]

  6. Mel Johansen says:

    Recently at a campground the 50 amp service was only putting out 196 volts. The meter read 109-111 volts. I have a surge protector and want to know if this is an ample situation for my motor home.

    On another note, the ice maker in the refrigerator will work for a week or so and then starts to trip the GFI. After that I have to unplug the ice maker for the rest of the trip. I even used an extension and plugged it into another outlet. Any ideas?

    Thank you.

    • Mike Sokol says:

      Well, I suspect your 50 amp service is running 2-legs of a 3-phase service, which at full voltage would measure 208 volts from leg-to-leg. That’s because of instead of your two hot legs being 180 degrees out of phase like in your home, they’re only 120 degrees apart. That’s OK since RVs typically don’t have anything powered by 240 volts anyways, just a bunch of 120 volt appliances run from one leg or the other. Your RV is really seeing 110 volts on each circuit which is a little low, but certainly within reason. Can you supply the name of the campground and I’ll contact them to verify my theory?

      For your ice maker, I wonder if the GFCI is being tripped by water dripping on circuitry somewhere inside the ice maker itself. That would allow 120 volt current to flow from the hot wire in the ice maker to the fridge chassis ground, and your RV chassis ground is dumping the current to the safety ground, which is exactly what it should do. But anything over 6 milli-amps of ground fault current will trip the GFCI breaker, which is exactly what it’s supposed to do. I would carefully inspect the ice maker for any torn gaskets that are allowing water into the electrical motors and such. If this is within warranty, I would simply ask for a new ice maker. In any event, please report your findings….

      Mike Sokol

  7. Brian Cloke says:

    Hello Mike.
    Thank you for a most interesting series on RV safety. I have been reading Part four Hot Skin.
    Ready, set,test.
    Using digital meter test. National electrical code allows 1 to 2 volts as being safe. If however you read 10 or 50 or 120 it is time to pull the power plug.
    Using non contact tester.
    The Fluke volt alert works very well as low as 40 volts. If your RV has more than 40 volts on the skin it will alert you to that fact. My understanding of this then is. If the skin of my RV shows less than 40 volts the Volt Alert will not respond or light up. Therefore using National code of 1 to 2 volts as being safe and any voltage above that as being dangerous I would conclude that the Volt Alert would lead me to think the RV is safe when it is not.
    If this thinking is correct it makes the Volt Alert a deceptive tool to use.
    Please enlighten me if I am missing something here.
    Thank you.
    Brian.

    • Mike Sokol says:

      Brian,

      Thanks for your thoughtful comments. In fact, the gold standard way to test for an RV hot skin condition is with the probes of a Digital Voltmeter poked between the chassis of the RV and a solid earth connection. Unfortunately, nobody does that type of test unless there’s a known shock problem they’re troubleshooting.

      The idea of using the Fluke VoltAlert came to me when I realized that most high-impedance RV hot skin conditions do indeed go up to around half of the line voltage (60 volts), while most low-impedance hot skin conditions go to full line voltage (120 volts). Also, many hot-skin conditions I’ve had emailed to me are intermittent and will come and go depending on which way you twist a power plug. Since the lower AC voltage threshold of electrocution is around 40 volts, the fact is that the VoltAlert will show you any potential “LETHAL” hot skin voltage of 40 volts or more.

      It’s not the ultimate test tool since it won’t measure chassis to ground impedance, nor will it give you an actual voltage reading. A VoltAlert just beeps at you and lets you know that touching the RV and the earth at the same time could be deadly. But it’s a simple, non-invasive test that anyone can do safely since there’s no need to touch the RV at all. I’ve had emails from octogenarians who now test their own RV’s and any other RV before they step into them, and a number of them have found hot-skin conditions which they avoided. And I’ve had an email where this non-contact test was performed after plugging their RV into a relative’s garage power outlet while visiting, and the mis-wired outlet energized the RV to 120 volts. I also had an email from someone who did this test on an old RV he was refurbishing, and when it beeped at him he measured the actual chassis voltage as 120 volts. He decided not to take his kids camping that weekend until he found and fixed the problem. He was grateful for the test since he had no idea his dog-bone adapter had a corroded ground pin which broke off inside the plug. And something as simple a a broken dog-bone adapter could have killed him or his child.

      So I’m sure this simple non-contact test has saved dozens and perhaps hundreds of RVing families from shocks and possible electrocution. And many RV technicians are now using it as a quick check on every RV they plug in. No, it’s not the ultimate test, but it will save lives. And it’s only $25 or so.

      Mike Sokol

      • Brian Cloke says:

        Thank you Mike for that explanation of the Fluke tool. As an aside. Many years ago when I was an apprentice in England a man was killed whilst working on a car by touching 12 volts. So by national code standards anything above 1 to 2 volts is still valid. Maybe fluke could come up with a tool that could read a lower voltage.
        I guess that a fluke is in my near future.
        Cheers.
        Brian.

  8. […] avoided if you have an understanding of how the RV electrical system work. Check out Sokol’s fourth installment discussing the hot-skin condition. For more information about your RV’s electrical system, […]

  9. dieta says:

    Larger Motor homes and travel trailers may be equipped with a 50-amp power cord that has 3 #6 wires for power and 1 #8 wire for ground. This power set up is said to have 2 legs, (or circuits) of 110 volts each. The plug is the now standard 4 prong 50 amp 240 volt type found on modern electric ranges. All kinds of power adapters are available for this plug configuration, the most important thing to note is that most adapters, dog bone or other simply put the same 110 volt power from the 110 volt wall receptacle on to both legs, (circuits) of the power cord. This limits total usable power to the power available at the wall receptacle or outlet. 50-amp service can be connected to a properly wired 50-amp 240-volt receptacle, which will utilize the 2 legs of 110 volts. Typically there is no 240-volt electrical equipment installed in production RVs until we get into the bigger rigs, Bus conversions, custom units, etc. So for the most part we see 110-volt washer dryers, air conditioners, and electric cooking appliances.

  10. Elmer Bulman says:

    Something often overlooked when the RV has an OPEN ground wire but connected to a 120VAC 2 wire connection. In this configuration the floating ground/chassis can assume a float level as much as 60 VAC because of the coupling capacitance of the RV 3 wire circuits. This capacitance between the 3 wires is always there but the leakage current is less then the trip level of a GFCI, it only shows up as a problem when the GROUND conductor is open/floating. I have measured the capacitance at the male pins of the 30A plug on our Class C MH at about 0.037 (H to G) and 0.040 (N to G) microFarads which amounts to be about 66 KOmms at 60 Hertz. At 120 VAC this amounts to about 2 milliAmps where a typical Class A GFCI trips at 6 milliAmps.

    • Mike Sokol says:

      Elmer,

      You are correct. And if you use a high-impedance volt meter to measure something like a crock-pot without a ground pin on its power cord, you’ll find that it actually have about 60 volts on the chassis. This isn’t dangerous to touch only because the fault current potential is so small. However, an ungrounded refrigerator or microwave can develop a much lower resistance internal fault that can source many mA or even amperes of current externally. Plugging that appliance into your RV’s electrical system will “reflect” the appliance’s hot-skin condition to the skin of the RV UNLESS the RV is properly grounded to the house or pedestal’s safety ground.

  11. Drew says:

    Mike,

    I enjoy all of your electrical safety articles- keep them coming! You are very specific and the articles contain the right amount of detail so that everyone can understand.

    Thanks again,

    Drew

  12. Scott says:

    Hi;

    We just bought a used 2006 Jay Flight 26BH travel trailer. The other day as I was cleaning the unit up I could have sworn I was getting zapped a tiny little bit, my wife tried touching the door frame where I had touched it and nothing. Tonight though it was definite, I Googled it and found your site, boy am I glad I did. I took my no touch tester out to the RV and it lit up like a Christmas tree. I immediately unplugged the trailer and of course the tester doesn’t register anything now. I’ve tried multiple plugs in my home all with the same result, I refuse to believe all of the plugs I tried are wired wrong. Based on what I’ve read (I wasn’t using an extension cord) it must be my shore power cord or the 120 V adapter?? Does this make sense? I will be talking to an RV tech but I want to have as much knowledge on my side as I can. Hopefully it is as simple as changing the adapter or cord.

    Thanks
    Scott

    • Mike Sokol says:

      I think that many (if not most) RV hot-skin conditions are caused by broken dog-bone/pigtail adapters, but you could have home wiring problems as well, depending on its age (pre-70’s is the worst). So at the very least, test your home outlet with a 3-light outlet tester, and follow up using your non-contact voltage tester. Here’s a video on how to test your home outlets for polarity: http://www.youtube.com/watch?v=jF3Ntoa8ab8

      Then I suggest you simply buy the best dog-bone adapter you can find and see if that corrects your problem (I’ll bet it does). The cheap/import molded adapters are notorious for the ground breaking internally, which is the primary suspect. Try this and let me know how it works.

      Mike

      • Scott says:

        Hi Mike;

        My electrician buddy came over tonight and we tested the plug among a few other things, the trailer was sitting at 34 volts when energized! Turns out it was the adapter, the ground contact on the female side of it was splayed out a bit, so it actually created an intermittent Hot Skin situation. When we first started our investigation the trailer was not energized…..what the heck? Tested plugs, extension cords etc. As we were trying things the trailer would become energized and then not and so on because as we were un plugging and plugging the cord to the outlet the adapter would get “jiggled” and make contact then not. I got a cheap adapter for the time being as there isn’t much for RV products in my neck of the woods. I will get a better quality one when I can and keep the cheapy as a back up. Anyway, all things are good now, thanks very much!

        Scott

  13. Jason says:

    Just wanted to clarify, a non contact voltage tester does NOT require you to act as an earth ground (some older models may have required this, but I haven’t seen or owned one since 2005 that required this). The whole unit is plastic, thus being an insulator, and runs off of 1 or 2 AA or AAA batteries, depending on which model you get. It functions by reacting to the magnetic field created when electricity is present in a conductor (wire, rv frame, etc.). I am writing this to help make sure you are giving the best information to people. The articles are great and I appreciate you writing them.

    • Mike Sokol says:

      Well, any Non Contact Tester does not operate on a magnetic field. If that was so, they would only work on circuits with current flowing. Actually, they work by capacitively coupling both to the circuit being tested (via the tip) and the body of the tester (via a small metal plate inside). Both the tip and body of the NCVT tester are indeed insulated, but the capacitance coupling allows AC voltage (60 Hz) to be detected by the very high impedance discriminator circuit. Essentially, it’s listening for “hum”. Now earlier NCVT’s didn’t have a very large sensor plate and required a hand to encircle the body of the probe for the earth coupling. But later model NCVT’s have a much larger internal capacitor plate in the body of the tester, and thus will beep when inserted into an active circuit even without a human hand on the body of the tester to add extra ground-plane capacitance. But there must be a ground plane link of some time for a NCVT to beep. For instance, if you’re standing inside of an RV that has its skin electrically energized (hot-skin), then pointing your NCVT at the door frame will NOT cause it to beep. That’s because both your hand around the body of the tester and the tip of the tester are at the same electrical potential. But standing inside of a hot-skin RV and pointing a NCVT at the ground outside WILL cause it to beep. I’ve tried this many times and confirmed that’s how it works. Also, the NCVT manufacturers themselves warn you that if you’re on a very tall fiberglass ladder doing a test, then your body/hand and thus the capacitive sensor plate in the body of the tester can be elevated high enough above the earth’s ground plane that your NCVT can fail to beep on a live circuit. I’ve tried this with an 8-ft fiberglass ladder and everything still worked, but perhaps standing on a 16 ft fiberglass ladder could de-couple you from the earth enough to shut down your NCVT tester.

      I’ve discussed this at length with the various NCVT manufacturers, and this is how it all works. Not magnetic, but rather capacitive coupling.

  14. Dbm says:

    I plan to install an onan Microlite 2800 in my van. The generator has a pigtail of three wires, green – white – black. I plan to run these wires to an outlet. Then I plan to plug a cable into that outlet and feed a breaker panel. For shore power I plan to have a second outlet that is supplied by a 30 amp male plug mounted in the body of my van. To use shore power I will unplug the supply cable for the breaker panel from the generator outlet and plug it into the outlet wired to the body mounted plug. My question is were should I bond ground and neutral? My thought is that I should not do the bonding in the breaker panel but I should do it in the outlet being supplied by the generator??? Correct?

    Thanks

    • Mike Sokol says:

      That’s correct. You must NEVER do a Ground-Neutral bond in your RV’s breaker panel. But you’ll want the Ground-Neutral bond in your generator. If your generator is already G-N bonded, then it should work as you describe. If your generator is NOT G-N bonded already, you can bond it in your Generator outlet as you planned.

      The key is that your RV’s electrical system mush have an isolated Neutral, and either the generator or the service panel of the shore power it’s plugged into will supply the G-N bond from ONE point alone.

  15. […] frame becomes electrified and very dangerous. For more information on this please check out the No-Shock-Zone website. They have many terrific articles on RV electrical safety including how to use the Non-Contact […]

  16. Susan says:

    Is the following non contact RV hot skin tester with LED light the best/suitable for a 2014 Class A Itasca 27N motorhome ? Fluke LVD2 Volt Light

    Also saw says operating temp max 50 Celsius (82F) – does this mean it wont work if temp 100 degrees ? Had 2 weeks of this temp last summer.

    I am not very electrical knowledgeable and don’t want to carry light and tester. Thanks

    • Mike Sokol says:

      Yes, that model Fluke tester should work just fine. And your temperature numbers are off a bit since 50 degrees Celsius is actually 122 degrees Fahrenheit. So unless you’re camping in Death Valley on a really hot day, all will be well.

  17. JTT says:

    My wife and I are waiting on the arrival of our first RV (29′ TT) and I have been gobbling up as much info as possible on RVing. I saw the news about the young boy killed by a hot-skin condition and started researching it since I have two young daughters and wish to protect them from such an event (among others). The articles you have written are great and very helpful for someone like myself who has a healthy respect for electricity, but a limited understanding of it.

    You mentioned in part IV under “Ready-Set-Test” that one should look for metal entering the ground (power pedestal, water pipe) and place one lead on it and the other lead on the RV. Since the test leads are only 10-12 inches long, how do you go about doing this if no metal entering the ground is close enough to the RV for the leads to reach both objects? This may be a dumb question and I’m probably missing the obvious, but…?

    • Mike Sokol says:

      For quick earthing tests I stick a long screwdriver in the ground. But even then you have to be careful not to poke through any underground wiring or plumbing at a campground. They often don’t bury the wiring as deep as code now requires. That’s why I’m an advocate for using a Non Contact Voltage Tester (NCVT) for doing quick hot-skin checks. If you do find a hot-skin voltage that way, then it’s time to establish a ground connection for further testing. But being sure that any test ground is actually at earth potential is a real problem, even for electricians and engineers. See my video on how to use a NCVT to check for an RV hot-skin condition at http://www.youtube.com/watch?v=Y8h64X33aKg

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