"One item I feel is important and should be passed along to the readers concerns the use of leveling boards/blocks and the grounding of a trailer. While taking a class on electrical issues involving fifth wheels, motor homes, pop-ups and trailers it was noted that campers should NOT place their metal leveling jacks in direct contact with the ground be it earth, gravel, sand, blacktop or concrete. This will in effect ground the trailer through that action. A camper should only be grounded through the electrical plug only.
"With that in mind, it is important to place thick plastic or rubber between the ground and the jack. If wood is used (as in leveling boards), plastic or rubber should still be used between the jack and the ground as wet wood can conduct electricity. The typical orange squares sold at RV supply stores are excellent to use; but there are other low cost options such as nylon kitchen cutting boards and pieces of plastic deck boards cut to a proper length. There are other options but these are two of the easiest to obtain."
We could envision crowds of RVers rushing Walmart, clearing out store stocks of plastic cutting boards, provided this matter of not grounding an RV through levelers were true. To protect our readers (and potentially Walmart security) we ran the issue past our "resident expert" on RV electrical safety, Mike Sokol. Mike has 40 years with industry, does the RV electrical safety lecture circuit, and is author of the book, No~Shock~Zone RV Electrical Safety. (Available at Amazon.)
Mike wants to set this matter straight, because there's a difference between "earth grounding," and "neutral bonding." To make our RVs safe, it's necessary for the ground wire in our shore power cord (the green wire) to be "bonded" to the neutral bus of the electrical service panel our rig connects up to. This same panel makes a connection to a ground rod, what Mike likes to refer to as an earthing rod. This ground rod serves two purposes. First, if electrical insulation should fail, and electrical power be floating on exposed metal, the ground rod as a path to help prevent electrical shock. Secondly, a ground rod also provides a path for static electricity (even lightening) to make its way safely to earth.
Where folks sometimes get confused is in the matter of the bonding the ground to the neutral. Under the National Electrical Code, there should only be one point in a system where the ground and neutrals meet – and no more. However, that same code says you can have multiple ground rods. Putting your RV's stabilizers or levelers in direct contact with the earth could be likened to having more earthing rods – and no danger to it.
Mike feels that many people – including some electricians and electrical engineers themselves – get confused about this is issue is that the word "ground" has different meanings – and most of them have nothing to do with electrical ground wire safety. For example, you'll find in most rigs that the frame of the RV acts as a "ground" for 12-volt DC power. The frame acts as a return path for voltage, and functions just fine, whether hooked up to earth ground when the shore power cord is plugged in, or when completely disconnected from a shore power connection when driving down the road.
In any event, Sokol assures readers, it's perfectly fine to put down your levelers or stabilizers without adding any sort of "insulation" between the foot and the ground.