Will "hot skin" become a thing of the past?

Last week, the RV Industry Association (RVIA) announced that there's going to be a big improvement in the way RVs are wired. This change might eliminate the risk of "hot skin" in RVs made in the future.

This minor miracle is the result of a new rule in the National Electric Code that requires RV manufacturers to install a device that cuts off power to the RV when the ground connection to the campground power pedestal is missing. This device will be called a Grounding Monitor Interrupter, or GMI.

What It Does

If there's a poor or absent ground connection from your RV to the campground power, the RV will detect it and shut off the power. For example, this might be caused by a broken wire or badly corroded prongs on your power cord.  In the past, you might have been able to plug in without noticing the problem. With a GMI installed, you won't get power until you fix it. 

If your RV is fine but the campground pedestal doesn't have a good ground connection, the GMI will detect that as well, with the same result: no power to the RV.

Why the Ground Connection is So Important 

The ground wire is your primary line of defense against getting shocked. If something goes wrong in your RV (or any of the appliances) that might cause you to get shocked, the ground wire is there to drain away the electrical current so that it doesn't pass through you.

So, no ground connection = no protection for you. Ouch. 

The Good

Overall, GMIs will be a good safety upgrade for everyone. "Hot skin" is startlingly common, and it can be deadly. (Read my blog about hot skin, and how to detect it, here.) With GMIs installed in all new RVs, the hot skin problem will be mostly limited to RVs made prior to 2026.

If you want the same benefit as a GMI on your current RV, you can check for proper ground anytime with a simple 3-light tester. You can also test for electrical leakage to the RV's body in just a few seconds, with a simple Non-Contact Voltage Tester. For now, there are no GMIs on the market to retrofit existing RVs, but I think it's likely that in the future they'll be available.

The other good aspect might be that campgrounds are forced to do better maintenance on their power pedestals. I've encountered many a power outlet that showed signs of potentially-dangerous neglect: bug nests, burn marks, loose outlets, cracked or broken outlets, rust, water leaks, etc. Now that campgrounds will be unable to provide electricity to some campers if the power pedestal has a ground fault, maybe the number of those less-reputable connections will decrease.

The Bad

It will be a bad day when you drive 400 miles to begin a wonderful vacation, and find that your GMI-equipped RV refuses to give connect to the campground power pedestal because a grounding fault has developed. You'll have no option other than to rely solely on battery power, until you locate and fix the fault.

Locating the exact source of a broken ground requires some methodical troubleshooting with an electrical meter. Sometimes the cause is easy to find and fix (for example, a bad power cord) and sometimes it's going to require a deeper investigation (for example, a chafed wire inside a wall). Sometimes people will end up calling a mobile RV tech or hauling their RV to a dealership.

But before you go to that drastic step, make sure the problem isn't in the campground's wiring first. As I mentioned, a simple 3-light tester (pictured at right) or a more protective Progressive Electrical Management System will let you know if there's a wiring issue in the campground power.

Another easy thing to check is your own power cord. If you can borrow somebody else's cord, that's a simple way to see if your cord is the problem. Beyond that, you'll need a good meter and some knowledge—or a technician.

Another undesired outcome of GMIs could be that temporary campgrounds, like at certain rallies, may have more electrical hassles than usual. Often RVs are sharing a power connection at these rallies. If one of RVs has an electrical problem and no GMI, it may cause other RVs with GMIs which are sharing the same outlet to shut off.

The Confusing

You might think, "Doesn't the circuit breaker or a GFCI already protect me from these sorts of problems?" That's a very reasonable question.

The simple answer is, no. Circuit breakers in the RV and the power pedestal don't help in this case. They're designed to protect against overloads. A circuit breaker doesn't detect ground faults, unless it's a GFCI-equipped circuit breaker.

So, what about a GFCI (Ground Fault Circuit Interrupter)? A GFCI in the campground pedestal would help—if it was installed. But they aren't installed on campground 30 and 50-amp RV outlets, because they are prone to false alarms. There are a number of normal wiring situations and devices in an RV that will trip a GFCI, even when no real danger exists. So, you'll see a GFCI on a 15-amp or 20-amp outlet in a campground, but not on the bigger outlets.

You might also ask, "Doesn't my Electrical Management System tell me if there's no ground, and cut off the power?" Yes, it will—if the grounding problem is in the campground power outlet. But the EMS can only test the campground's power supply. It can't tell you if there's a bad ground inside the RV.

Finally, there has been some misinformation published which implies that you'll have to install a GMI in your existing RV to be "compatible", or that campground power pedestals will also have GMIs installed. This isn't true. Existing RVs need have no modifications, and campground pedestals aren't getting GMIs.

Final Thoughts

There are a few things we don't yet know about how GMIs are going to affect our experience. For example, we don't know if there will be unintended side effects of the GMI, such as "nuisance tripping" (false alarms).

We also don't know how reliable or durable GMIs will be. It seems reasonable that GMIs will need to be replaced periodically, like other electrical safety devices. But how often? Will the life of the GMI be shortened by voltage spikes, brownouts, or overloads? Will GMIs have a self-test feature like a GFCI?

Because of these open questions, it's likely that RV manufacturers will install the GMI in such a way that it can be easily seen and tested by the end user, much the way that GFCI outlets and GFCI circuit breakers are installed. GMIs should also be easy to replace, and not buried deep inside a rat's nest of wires. 

Finally, it's not clear when the first RVs will be manufactured with GMIs. RVIA says only that "The RV Industry Association plans to set the exact 2026 dates for adoption and enforcement... in November 2025." Once they have that meeting and announce the consensus, we'll have an idea of whether late 2026 or 2027 be the first model year to have GMIs.