By Mike Sokol
It appears that there are many first-time RVers here now, and while it is my 10th year of writing articles for the RV industry, this may be one of the first times you’re reading my RVelectricity columns. So, Welcome, and I promise you this will be (mostly) painless.
I’m going to start this First-Timer series with one of the most important things you can learn about … Hot-Skin Voltage. I have literally dozens of other published articles on how and why this occurs. But for now we’ll just cover the basics of what it is and a super-easy way to test for it.
Basically, you should NEVER feel a shock while touching your RV or any appliances such as a toaster, hot plate or laptop computer. If you do feel a shock that means there’s a voltage appearing on the skin and chassis of the RV or appliance. For something like a toaster oven we generally call this a contact or touch voltage. But for an RV it’s typically called a Hot-Skin Condition. That’s because the “Skin” of the RV is energized with anything from 30 to 120 volts of AC. Now this voltage doesn’t come from your RV’s battery or inverter. Nope, it comes from the outlet you’ve plugged the shore power cord into. Much more on how that happens later.
And it’s not just the skin of the RV that can become energized – it’s virtually everything metal from the door frame to the trailer hitch to the tow vehicle if it’s still attached. So if you have 50 volts on your bumper, you have 50 volts on the trailer hitch, and 50 volts on the steps, etc. And even 30 to 50 volts of hot-skin on an object can be dangerous to you if you simultaneously touch the electrified object while standing on the damp ground. And this voltage can easily reach 100 or even 120 volts, so it can be quite dangerous. And when I say dangerous, I mean death from electrocution. So never accept feeling a shock from anything. Get it fixed immediately.
But is there a way to make sure your RV doesn’t have a hot-skin voltage without touching it with your bare hand? Yes, indeed there is. I developed and promoted this simple test using an off-the-shelf tester you can find at any big box store or on Amazon. It’s called a Non-Contact Voltage Tester (or NCVT for short) and it’s normally used by electricians to tell if a wall outlet is energized. However, it works GREAT to detect a hot-skin over 40 volts on the skin and chassis of your RV, sometimes from a foot or more away.
Also note even if you purchase a NCVT that’s rated to detect an energized wire from 90 to 1,000 volts, just because your RV has a few hundred square feet of energized skin, that NCVT rated for a low of 90 volts will easily find an RV with a hot-skin below 40 volts. And that’s about where the voltage can push enough current through your heart to stop it.
Let’s be clear: The voltage is the electrical pressure that pushes current through you and your heart. And it’s the current that can stop your heart from beating. So if you do feel any kind of shock while touching your RV or if a Non-Contact Voltage Tester beeps from an inch or a foot away from your RV (and yes, you can safely touch the skin, chassis or steps of your RV with an NCVT), then it’s time to disconnect from shore power and get the campground maintenance crew to determine if the problem is in the pedestal, or perhaps in your own shore power cable. More on how to determine that next time.
Click on the picture to watch a video of me using my VW Micro-Micro-Bus to demonstrate how this detection works. It’s completely safe to perform this test yourself, and you can safely touch the tip of the NCVT to an energized surface without getting shocked (but don’t use your hand – seriously).
If the NCVT tester does beep at you, you can be pretty confident that something is wrong with the ground wire in the power cord connecting your RV to the campground pedestal or your home electrical outlet. Much more on that later, but for now go get an NCVT and start using it. Here’s one of the most affordable Non-Contact Voltage Testers that I use in my RVelecticity seminar which only costs $15 or so, and which can save your life or the life of one of your family members (even the furry ones).
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.
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