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RVelectricity – Shocked when touching your RV? This is a deadly serious problem. Do something!

By Mike Sokol
Dear Readers,
Spring is here, and with it I’ve received a bunch of emails and postings on my RVelectricity Facebook page about readers feeling a shock from their RV while plugged into home power using a dogbone adapter or a campground pedestal. There are a lot of guesses and wrong information floating around the internet and social media platforms, so I’m going to clarify what a hot-skin is here.

DANGER: If you feel any kind of shock while touching your RV and standing on the ground, immediately disconnect your RV from shore power and read below. This is potentially a very dangerous situation. 

What is a hot-skin?

Hot-skin is a term long in use by the RV industry for decades before I started writing my No~Shock~Zone and RVelectricity articles. Basically it’s anytime you feel a shock while touching any part of your RV while standing on damp ground.

Is it dangerous?

Yes, it certainly can be. There are a lot of variables involved. But once the voltage potential on the skin and chassis of your RV reaches around 30-volts AC, and if the ground you’re standing on is damp, you can feel a shock. Depending on how much fault current is available and how wet the ground is, this can be anything from a mild tingle to a huge shock that can put your heart into fibrillation, which can be deadly.

What doesn’t cause it?

Urban legend has a hot-skin condition being caused by the hot (black) and neutral (white) wires in an extension cord or outlet you’re plugged into.

But that’s simply not true. All RV electrical systems have their neutral and ground conductors isolated from each other. So reversing them doesn’t cause a hot-skin voltage on your RV chassis. For that to occur you must have a broken or missing ground wire (Equipment Grounding Conductor) between your RV chassis and the main service panel that feeds power to your house or campground.

What does cause a hot-skin condition?

Well, two things cause a hot-skin condition. The most important one is the ground wire – sometimes called safety ground and officially called the Equipment Grounding Conductor or EGC in the National Electrical Code book. For a hot-skin voltage to occur you need to have lost your Safety Ground connection. This is the ground pin or lug on your shore power connection. It’s the contact at the top of any 30- or 50-amp plug.

Current source

Next you need to have a source of ground fault current. That can be anything from the normal 2 or 3 mA (milliamps or 0.002 amperes) of leakage currents in your RV, up to a 20 or 30 amperes of available fault current if a wire was pinched or a screw driven through it inside of a wall.

Will a ground rod stop a hot-skin?

No, it will not. A grounding rod’s main duty is to provide a path for nearby lightning strikes to go deep into the dirt before they side-flash and damage more electrical gear. And they are only required to exist at the service panel, not the campground pedestal and certainly not connected directly to your RV.

How do I troubleshoot a hot-skin voltage?

First you need a basic 3-meter kit from Southwire or Klein which you can get HERE. The initial test should be verifying you have a hot-skin voltage on your RV.

The easiest way is to use a Non-Contact Voltage Tester like this one available from Amazon HERE. Simply power it on, test it on a powered outlet to make sure it’s actually working, then touch anything metal on your RV with the tip of the probe. If it lights up and beeps when you make contact, then your RV has a hot-skin around 40 volts AC. If it beeps from several inches away, then your RV hot-skin is around 80 volts AC. And if it beeps from 1 to 2 feet away, then you have a very dangerous 120-volt hot-skin condition.

How do you find the problem?

Once you’ve confirmed a hot-skin voltage on your RV, you need to find why you have a lost ground wire. The best way to begin is to check the electrical outlet you’re plugged into for proper ground and/or polarity. Use a simple 3-light cube tester on the outlet which you can get from Lowe’s or HERE, and if you’re plugged into a 30-amp outlet you can use a 30-to 15-amp adapter. Read more and watch my video on how that works HERE.

Yes, I said polarity when I already told you it won’t cause a hot-skin voltage. But it does suggest that whoever wired an outlet with reversed polarity didn’t do something else properly. If you do get an open ground indication, you’ll want to get a technician or electrician to correct the problem. And no, just adding a ground rod does not fix it. They need to make sure the ground wire is bonded back to the service panel’s neutral bus.

Look for an extension cord and dogbones with broken grounds

A surprising number of hot-skins are caused by using an extension cord with a lost or broken ground pin, or an adapter with a ground that’s broken internally. So replace that cord or adapter immediately and retest. If you still have a hot-skin voltage then you haven’t identified the actual problem. But it’s possible to have several things wrong at the same time.

Final test

Go ahead and plug your 15-amp adapter into a standard GFCI outlet on your house. If the GFCI outlet trips, then you must have more than 5mA of ground fault current. That suggests something else is wrong inside of your RV electrical that’s creating excessive fault current and needs to be corrected. I’ll be adding a list of possible ground-fault sources to the bottom of this article soon.

If your RV doesn’t trip the GFCI after you’ve corrected the broken ground connection, then your hot-skin voltage was caused by a low-level fault current that is now being properly mitigated by the ground conductor. So all is well, and you stopped the hot-skin voltage by repairing your broken ground connection.

Don’t accept a shock as normal!

Never leave an RV unattended that’s shocking you. You’ll want to unplug it from shore power immediately and repair the problem. Here are a couple more articles I’ve written about the inner workings of hot-skin troubleshooting that are worth reading.

Testing for a Hot-Skin Voltage

How to diagnose a Hot-Skin Voltage

ADVANCED CONCEPTS

By popular request I’ll be adding a few advanced hot-skin troubleshooting techniques here later tonight. So come back tomorrow and learn more about the various sources of fault current that can cause a hot-skin voltage if your ground conductor is broken. See you later.

Let’s play safe out there….

Mike Sokol is an electrical and professional sound expert with 50+ years in the industry. His excellent book RV Electrical Safety is available at Amazon.com. For more info on Mike’s qualifications as an electrical expert, click here.

For information on how to support RVelectricity and No~Shock~Zone articles, seminars and videos, please click the I Like Mike Campaign.

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Vanessa Simmons
5 months ago

I’d like to send mike a question but can’t find anyplace to do that…Is there a link for it that I am missing?

Admin
RV Staff (@rvstaff)
5 months ago

Hi, Vanessa. You can just ask Mike a question in the comments under his posts. He reads them and will respond. Or, this is part of the intro to his weekly J.A.M. Session: “Welcome to my J.A.M. (Just Ask Mike) Session, a weekly column where I answer your basic electrical questions. … Send your questions to Mike Sokol at mike (at) noshockzone.org with the subject line – JAM.” Thanks for asking. I’m sure he’ll have an answer for you. (The more I get to know Mike, the more I think he has an answer for pretty darn near everything. Just sayin’.) Take care. 😀 —Diane at RVtravel.com

Vanessa Simmons
5 months ago
Reply to  RV Staff

Thank you.

Admin
RV Staff (@rvstaff)
5 months ago

You’re welcome, Vanessa. Have a great day! 😀 —Diane at RVtravel.com

KK Idaho
5 months ago

We had a hot skin condition on our “regular” house trailer that turned out to be an open element in the hot water heater thus putting the whole plumbing system at 120 volts. So it can be very dangerous! 😡 

Betty
5 months ago

We once had hot skin when we were boondocking. We were near a light pole in a parking lot in an event field. We were not plugged into anything, nor did we even own a generator at the time. But when we touched our camper we got a mild shock. Didn’t see any exposed wires on the pole; it looked normal. But we moved to another spot and the trouble went away.

Mike Sokol
5 months ago
Reply to  Betty

Interestingly, I wrote about this phenomenon in 2017. If you park your RV under high-tension power lines, and it’s not plugged into shore power or grounded in any way, you can have an induced voltage on the entire RV of up to 10,000 volts and 5mA of current. Now this isn’t dangerous, but it can feel like grabbing a spark plug wire on a running lawnmower engine. You experience this same effect just driving a car under power lines, but the current is usually so low in amperage that you can’t feel it. Read this… https://www.rvtravel.com/hot-skin-condition-from-overhead-power-lines-not-dangerous/

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