Breaking News on Stray Voltage
By Mike Sokol
Within hours of publishing my article Focus on Stray Voltage, we received this very interesting comment from Richard Iddins.
We just left a park in Alberta Canada. Where this morning when I was greasing the suspension on our trailer and when I touched one of the axles with my arm I felt a tingle. I checked the frame of the trailer with my non contact electrical tester and found it to be hot. I then checked the electrical pedestal and found it to be hot also. I then, with my volt meter stuck the black probe into the ground (Dirt) and the red lead to a screw on the pedestal. And found there to be 40 volts. I disconnected the camper and rechecked and found the same voltage.
I then checked other pedestals in the park and found all of them to show voltage to ground. (Metal pedestal to ground). The camper next to us was a metal skinned unit that was also showing hot. I checked from the skin of the unit to ground and found the same 40 volts.
When I notified the campground they were receptive and called an electrician who was there within the hour and after checking he called in the local electric provider who also sent in one of their guys.
Before leaving the campground I requested a refund for the night and they stated that they do not give refunds.
The question I have is why would my EMS system not have shut down and given a code to tell me that we had the condition. Also I us the yellow plug in testers that have the 2 yellow and 1 red lights that will look for Open ground, open neutral, open hot, Hot/ground reverse, hot/ new. Reverse and correct. This tester did not show a fault either.
Please let me know your thoughts. —Richard
Well, I have a potential answer for you already. That’s because I’ve been studying this phenomenon for the last 8 years or so. While EMS systems and 3-light testers can find maybe 99% of all hot-skin stray voltage, there’s a really big miswiring condition I’ve named a Reverse Polarity Bootleg Ground (RPBG) and which can’t be detected by any current surge protector technology, nor can it be disconnected from the hot ground condition created by it. Pretty scary, isn’t it?
Interestingly when I first discovered this RPBG effect none of the test gear manufacturers knew about it, or that their meters couldn’t find it. That’s also when I developed the proximity test for an RV hot-skin stray voltage using a standard Non-Contact Voltage Tester.
See my initial article on it here, which was first published in Electrical Contractor and Maintenance Magazine where I introduced the concept of RPBG wiring to the electrical contractor and test industry.
I’m betting that’s what’s going on at this campground. If that’s indeed the case, then it’s a life-threatening situation that should be shut down and corrected immediately.
Let’s play safe out there….
The article above notes a 40V difference. Your referenced article uses a 90V+ detector. Should we be using both a low voltage and a high voltage Fluke detector?
Ah, confusing isn’t it. Both things are right. A NCVT listed for 90 volts has that rating for testing something as small as an extension cord or electrical outlet. But if you energize something with a lot of square feet of surface area (like your RV), that same “90-volt” tester will signal down as low as 40 volts. I’ve done this hundreds of times so I know it works. Here’s a video of me discussing how it works: https://www.youtube.com/watch?v=obeh9m4OMv4 and another one demonstrating the effect at 40 volts using a NCVT rated for 90 to 1,000 volts: https://youtu.be/Y8h64X33aKg?t=172
Hey, would I lie to you???
Great information. I have been an RV’er for the past year and when we purchased our motorhome, we also purchased an electrical diagnostic surge protector. Over the past year, the device has saved us from faulty wiring at pedestals. At Ocklochnee River State Park, Florida our diagnostic surge protector indicated a hot neutral and no ground. We alerted the campground staff and found out that the entire campground had very recently been re-wired with new pedestals. I checked a few other nearby sites and found faulty wiring on the 3 sites, down for ours but the other direction, the pedestals were correctly wired. The next morning, they electrical contractor came out and found that the wiring was incorrect and that line served the 3 sites that I had found faulty. Another note to this particular circumstance: 2 days later, people showed up at the site next to ours. Their class A motorhome had been at Camping World, being rewired as they had fried their electrical system after plugging in at the campground. They just thought their motorhome had experienced an electrical problem but they did not realize it was due to the faulty wiring at their site. They went to the Campground office and filed a claim and the State Park was going to cover their very expensive electrical repair. I cannot speak highly enough about testing every pedestal prior to hooking up.
This is the best reason to get an advanced surge protector for your RV. And best protocol would be to test the pedestal power BEFORE you even pull into the campsite.
Chuck and I are committing every possible resource we have to get the Stray Voltage Patrol up and running as quickly as possible. Expect updates every week and beginning operations by the end of July.
In the meantime, be sure to test EVERY pedestal for correct power before plugging in your shore power cordset, and consider purchasing an advanced surge protector for your own RV.
Also, if you know of any news outlets that would like an interview with me about RV electrical safety and our Stray Voltage Patrol please contact me directly at email@example.com. I can do radio, television, newspaper, social media, or even something on a forum you already belong to. Many of you have already read my responses as jmsokol on your own forums.
Looks like I need to change my habits. I keep a NCVT handy when I plug in, but since I use a surge protector that runs a circuit analysis first, I don’t usually check with the NCVT. Perhaps I should get in the habit of checking the pedestal with the NCVT before I even plug in.
I think that’s the best procedure. We’re finding a lot of campgrounds with the entire pedestal showing a hot-skin / stray-voltage since the entire box has lost its EGC ground. We’re going to know much more once we can start gathering intel from hundreds of SVP’s (Stray Voltage Patrols) around the country. Right now I can only roughly estimate just how many campgrounds and pedestals are affected, and in which ways. I’m guessing that in 12 months we’ll have a few thousand data points to mine for trends.
Mike, Thanks for your response. Am I correct in thinking this could be caused by incorrect park wiring or an incorrectly wired camper?
In this case, since there seemed to be numerous RVs connected to different pedestals which exhibited the same RV Hot-Skin Stray Voltage, that implies that something was miswired in the campground’s electrical distribution system. If only a single RV exhibits a Stray Voltage, then the problem is probably in that single pedestal or the RV’s own shore power cordset or adapter.
Good troubleshooting technique involves a divide and conquer mindset. That’s why I always like to get a big-picture overview of a failure situation before I start swapping parts. You want to avoid any “spray and pray” mindset which is very expensive and often causes more problems than it solves.
There’s also a logical mindset of when you hear hoofbeats, think horses not zebras. That is, start with the most common possible explanations first, and only then get more complicated.
Finally, Occam’s Razor is a logical principle I use all time and which is largely attributed to Sherlock Holmes novels. But it originated with William of Occam back in 1300 AD. It states that the simplest explanation is usually the correct one, so don’t try to overly complicate a problem.