🟦 Are little shocks okay?

A question from a No~Shock~Zone reader…

Dear Mike,

I keep getting different answers from the various forums I’m on, as well as my RV neighbors who think they’re being helpful. But someone said you’re the authority on this topic, so here goes. Me and my kids sometimes feel a small shock when we touch the door handle or steps on our camper when it’s plugged into an outlet in our garage with an adapter. It’s not exactly like a static shock. It’s more of a tingle that seems to come and go. I finally called the dealer where I bought this camper a year ago, and he said not to worry about it. He says hat feeling a little shock is normal and not dangerous. So, do I have anything to worry about?.

Thanks in advance – Pretty in Pink

Dear Pink,

First of all, ANY electrical shock is dangerous. There’s really no such thing as a little shock being OK.  You and your family are playing a game of electrical Russian Roulette, and that rarely ends well. You need to find and fix the electrical problem causing this right now, before somebody gets seriously hurt or killed. In the USA alone there are 1,000 deaths per year from electrocution, and 4,000 more injured seriously enough to require hospitalization. While the vast majority of these deaths are contractors and roofers, dozens of RVs owners are seriously shocked and a few may die from electrocution each year. Sadly, many of those injuries and electrocutions were caused by “little shock” situations that became more serious and turned deadly.

How much of a shock is dangerous?

FYI: It only takes about 20 mA of electrical current (20/1000 of an amp) to cause your body to clamp down and not be able to let go of an energized wire. And 30 mA of current (30/1000 of an amp) for a few seconds can cause your heart to go into fibrillation in a few seconds. So just 30 volts AC with 30 mA of available fault current can kill you if your hands and feet are wet. That’s only about 1 watt, less than the power of a small nightlight bulb.

To see something REALLY interesting, here’s the first video I made showing an RV hot-skin condition ON PURPOSE. Yes, I regularly do these type of experiments to find better ways to measure dangerous electrical conditions and learn how to fix them. Don’t try to replicate these demonstrations youself a s they’re potentially deadly. I’m extremely carefull and take all safety precautions with these demonstrations. Kid’s don’t try this at home!

What is this hot-skin voltage I keep hearing about?

An RV chassis and skin with ANY significant voltage above earth potential (5 volts AC is max) is proof that you’ve lost your RV’s safety ground connection or it’s been corrupted at teh pedestal. Now, by itself an open ground connection won’t cause an RV hot-skin voltage condition, but nearly anything inside your RV plugged into its electrical system will cause some leakage current to the RV chassis-ground. And that leakage will show up as a hot-skin voltage of varying degree. The really dangerous thing is that sometimes those can be high-impedance leakage currents that aren’t particularly dangerous. And that’s when you feel a “little” shock. However, that same “little” current can quickly become low-impedance / high-current leakage in a heartbeat, and that will almost certainly kill you if you touch the RV with wet hands and feet. It’s just a matter of degree, and you never know what that degree is. So any feeling of shocks from your RV or appliance is a warning to turn off the circuit breakers and disconnect the power plug immediately.

What causes a hot-skin voltage?

If you do have a proper RV safety ground back to the service panel, then it should be impossible to develop more than 5 volts on your RV skin. It will harmlessly drain away the small currents from normal high-impedance appliance leakage, as well as trip the circuit breaker form huge currents that result from abnormal low-impedance leakage, such as a screw driven through a wire inside your wall.

So if you measure more than 5 volts between the earth and the chassis of your RV there’s a serious problem with your safety ground. This is usually as simple as a broken or loose ground contact on your extension cord or dog-bone adapter, but can also be due to a problem in your campsite pedestal or home power outlet. Old garages are especially dangerous since they can be ungrounded for years without you knowing it, and the first time you plug an RV into it there can be a deadly hot-skin condition. And certainly a worn RV pedestal outlet can have corrosion or loose contacts, and that can cause an RV hot-skin condition.

Old garage outlets can have a Reverse Polarity Bootleg Ground (RPBG)

There’s one other really dangerous mis-wiring condition that I’ve seen at dozens of old garages and concert stages around the country. It’s something I call an RPBG (Reverse Polarity Bootleg Ground). This can happen when a DIY guy or old electrician tries to add a grounded outlet to a pre 1970 non-grounded electrical system by simply putting a jumper wire between the ground and neutral screws on the back of the outlet. But if the black and white wires are accidentally reversed, then the hot wire is sitting at zero volts, and the ground and neutral wires are at 120 volts. Note this is not the same thing as a simple “Reversed Polarity” where only the Hot and Neutral Wires are reversed, but the Ground Wire is connected properly. That condition alone will NOT cause a hot skin condition if all other wiring is done correctly.

A 3-light tester can’t find an RPBG

However, you can’t find this RPBG condition using a 3-light outlet tester, and a voltmeter measuring between H-N, H-G and G-N will report the outlet as safe, when in fact it will electrify anything you plug into it that has a ground plug. And there’s no surge or voltage protector product on the market that will detect or disconnect your RV from a RPBG outlet. They will report that everything is fine with an RPBG outlet, when in fact your entire RV and connected tow vehicle has been hot-skin electrified to 120-volts. The simplest way to detect this dangerous condition is by using a Non Contact Voltage Tester.

A Non-Contact Tester can easily find a hot-skin voltage

Watch this video where I demonstrate how to use a Non-Contact Voltage Tester to find an outlet with a Reverse Polarity Bootleg Ground miswiring condition.

Never accept feeling a shock!

The bottom line is NEVER accept feeling any shock from an RV or appliance. A shock is a warning that the next time somebody touches your RV they could very well die from electrocution. I think it’s socially irresponsible to expose your family and others to this potentially deadly situation, so get it repaired immediately. If you’re not 100% sure that you can measure and work around live electricity safely, then please contact a licensed electrician or RV technician immediately. The life you save could be your own, or that of a friend or family member.

Let’s play safe out there… Mike