Avoiding Lightning Damage: Part 1
Can SnapPads under your leveling jacks help reduce damage to your RV electrical system from a nearby lightning strike? (April 2023)
Staying safe in a lightning storm
Can RV SnapPads under your leveling jacks help reduce damage to your RV’s electrical system from a nearby lightning ground strike?
I’m done this study just in time for lightning season. For many years I made the claim that insulating pads under your RV jack stands would do nothing to protect your RV from electrical damage in the event of a direct lightning strike. And I believe that is still true, having performed a recent insurance inspection for a $500,000 coach that suffered a direct lightning strike on its roof.
However, for every direct strike, there are probably hundreds or thousands of smaller lightning ground strikes in the area that energizes the campground wiring. Could be as simple as a lightning strike on a nearby tree. Lightning takes multiple paths to earth, so it’s going to spread out for dozens or hundreds of yards before it totally grounds out.
And it’s possible that insulating jack pads could prevent something I’m now referring to as a whiplash effect through the ground and where a lightning current spike damages more of your electrical system due to secondarily grounding your RV, rather than insulating it from the ground.
Join me as I study this phenomenon and review technical papers on how insulating your leveling jacks might reduce electrical damage to your RV.
Just the basics
Here’s a screenshot of the video that got me interested in the effect, and why I contacted SnapPad about the possibility that their jack pads may provide extra protection for your RV’s electronics from nearby lightning ground hits. Note that when lightning hits the earth it doesn’t go straight down. Instead it takes multiple paths across the earth in varying depths in an attempt to find true earth ground.
A mind experiment…
Now let’s imagine that your RV is sitting on its metal jack stands on the wet ground, so it has a fairly good connection there. These jack pads are acting like a secondary grounding rod (albeit a rather small one). Now instead of the lightning electrical pulse coming into your RV from the pedestal, what if the current spike comes across the earth, is picked up by your grounded jack stands, and then tries to leave your RV via your shore power ground connection in the pedestal? I can only imagine that will wreak havoc with all of your expensive RV electronics.
What about a direct lightning strike?
Now as I’ve noted many times before, nothing can stand in the way of a direct lightning hit to your RV, and only a metal-skin RV can shield the occupants (you) from the lightning going directly through your RV. But I do believe that insulating pads from a company like SnapPad can reduce and possibly eliminate damage to your RV electronics if lightning hits nearby and you’re still plugged into shore power.
This is Part 1 of study that’s was funded by SnapPad. They’ve commissioned me to create a report on what I find, good or bad. So watch for Part 2 of this study in a few days as we get into lightning season soon and I publish more papers and studies on this effect. Now if only I could build a 30-foot-tall Tesla coil in the back yard to make a real lightning simulator. And then I have to find someone to loan me their RV. We shall see….
Let’s stay safe out there… Mike
I have said similar for years, in fact before we had SnapPads, I used to always put down rubber patio pavers under each motorhome jack because I never forgot the lesson that one of our local big dish satellite dealers taught me during those earlier home satellite days.
When 6-12 foot C-Band satellite dishes where popular, many people would install them many times 100 to 300 feet, sometimes further, away from their home or where their receivers were installed. The dishes themselves were always grounded and of course the coax continued that ground back to the receiver itself. The problem was that the manufacturers of almost all receivers and equipment at that time used three prong properly grounded cords, but the installers and businesses that sold and supported those dishes in those days started to notice a pattern that in houses that had proper grounded receptacle wiring that there were many repeat service calls for damaged and sometimes blown satellite receivers but in older homes where the owners often were forced to use 2-prong adapters (or worse, simply broke or snipped the 3rd cord (grounding) prong) on their receiver cords rarely to never seemed to have issues unless there was a much more direct lighting strike to their system, which of course nothing can protect from.
This was in the earlier days when the electronic and microelectronic industry was becoming more aware of the damage from static sources. I used to have to wear an anti-static wrist-strap while working/building computer systems before my workplace started coating the floors with anti-static paint...and then I went to a fairly local auction at the Cray Computer plant and was lucky enough to purchase anti-static generators that I incorporated over our work area and finally we were liberated from our anti-static shackles except off-site - but I digress!
The discovered logical reason these multiple grounded system were suffering damage was simple. If we take a hypothetical example of a direct lighting strike hitting something five or ten miles away from the satellite installation, the home might momentarily have a ground potential of 100,000 volts of static that is dissipating over that distance, while the ~100-300 foot closer satellite dish might have 150,000 volts of static to dissipate. A person's body standing in either location isn't usually susceptible to feeling that charge, but because the coax ties the dish and receiver together, if the receiver was grounded too, the receiver might experience a 50,000 volt difference, which it's electronics are susceptible too.
If we apply that to the typical campground scenario, your RV is supposed to only be ground at one spot - typically the campground power post (or your home power post). Generators and inverters set up an internal closed loop system, so that's not the same thing, but your power cord to that power post should have a single ground connection at it's source (the campground power post or campground distribution box or main properly grounded electrical box if at your home location). So while obviously not usually similar distances as in the satellite example unless you are using many extension cords in a hopefully reduced amperage situation if your jacks are grounded and not on pads and if a much closer direct lighting strike occurs somewhere in the park (let say a tree a few hundred feet or maybe even a quarter mile away), it is theoretically possible that there's a difference in potential between to power post or system and your grounded jacks that could possibly blow out some of your sensitive RV electronics. Admittedly probably a rare occurrence, but it is possible, which is why I prefer to minimize that chance by using SnapPads or other insulating material (I've always encouraged my children to at least use patio pavers under their stabilizers and front jack on their travel trailer since SnapPads aren't available for their specific use yet). The argument can be made that wet muddy conditions could lessen this protective measure, but it's usually less of a ground than direct metal contact in most scenarios.
Do what works best for your specific situation, but obviously in most cases a working good quality EMS surge protector is your first line of defense against most lighting and other electrical damage possibilities (remember the old Surge Guard "beware the power pedestal" toothed electrical monster advertising?), but keeping your RV insulated with only one known electrical ground is a worthwhile precaution in my book!
Mike, you should be able to find a junker RV with which to test the results of a lightning strike. As to that Tesla coil...