RV Electricity
with Mike Sokol
Dear Mike,
Thank you so much for your discussion of “hot skin.” I recently got a shock touching my small trailer and found out I had a bad extension cord.
A question: I use a surge protector between shore power and my trailer. The protector claims to detect lack of power, reversed polarity, open neutral and open ground conditions (using a series of green and red lights). I sometimes plug into a friend’s “garage” power outlet while camped in their driveway. Can I assume if the protector says I have power, correct polarity, no open neutral and no open ground that I am good regarding hot skin? Or is it still prudent to do your test? Thanks. —Lou
Dear Lou,
Take a look at this article I wrote for Gary Bunzer where I introduce the idea of an RPBG (Reverse Polarity Bootleg Ground) —and here’s the extended version I wrote to Electrical Construction & Maintenance Magazine.
While an RPBG miswired outlet should be uncommon and close to impossible at new campgrounds, they can happen surprisingly often in old basement and garage outlets inside houses built prior to 1960. So, plugging into your friend’s garage power while camped in his driveway could be dangerous.
Currently, standard test gear and methods cannot detect the hot-ground created by an RPBG miswired shore power outlet. And plugging your RV into one will certainly energize the skin and chassis of your camper to a full 120-volts with circuit breaker current of 20 or 30 amps. Also, even if your surge protector gives you the “all clear,” it’s still possible for your RV to develop an open safety ground internally due to vibration or corrosion. That’s why I think that using a simple NCVT (non-contact voltage tester) to test the chassis/skin of your RV after you plug it into shore power is a great safety check.
And, of course … any time you feel the least little shock while touching your RV means there’s something wrong with the grounding system of your shore power. It could be anywhere from the pedestal to an extension cord or any dog-bone adapter in the power line.
Mike Sokol is an electrical and professional sound expert with 40 years in the industry.
##RVT770
