Key Takeaways
- •The 2026 NEC now requires all new 30A and 50A RVs to include a Grounding Monitor Interrupter (GMI)
- •If your park's electrical system lacks a proper ground path back to the panel, GMI-equipped RVs will automatically cut power at your pedestal — no warning, no workaround
- •Parks wired correctly to previous NEC standards are likely fine — parks that cut corners on grounding are about to find out
A new device is showing up in RVs rolling off lots right now. It's called a Grounding Monitor Interrupter, or GMI. If your park's electrical system isn't properly grounded, it will refuse to let your guest's RV accept power.
No error message. No explanation. Just no power.
What a GMI Does
The 2026 Edition of the National Electrical Code, adopted in September 2025, finalizes a requirement that all new RVs with 30-amp or 50-amp electrical service include a GMI. The device checks the pedestal's ground connection before allowing current into the RV. If it doesn't find a clean, continuous ground path back to the electrical service panel, it shuts off. It also monitors that connection continuously while the RV is plugged in. If the ground is lost at any point, the GMI cuts power automatically.
The intent is safety. Hot skin conditions, where an RV's exterior becomes electrified due to faulty grounding, are a real hazard. GMIs are designed to catch the wiring failures that cause them before a guest gets hurt.
What It Means for Your Park
The GMI lives in the RV, not at your pedestal. Your infrastructure doesn't change. But if your infrastructure was never wired correctly, a GMI-equipped RV won't see a proper ground and will refuse to power up.
According to RVIA, parks wired in compliance with previous NEC editions should be fine. The problem is that not every park was. Ground rods alone at the pedestal are not an acceptable grounding method under NEC standards. If that's how your park was wired, you have an exposure. It will show up the moment a guest with a new RV pulls in and can't get power.
OHI named Tristan Ciceri of Electrical Works to the NEC's Code-Making Panel 7 to represent campgrounds on this issue. Ciceri has been clear: get your systems tested now, before GMI-equipped RVs start showing up in volume. A portable 30A or 50A receptacle tester can check each pedestal for ground continuity. If testing turns up problems, a licensed electrician needs to run a ground wire from the affected pedestals back to the source panel.
The Takeaway
This isn't a future problem. New RVs with GMIs are already being built. The guests who own them will be showing up at your park this season. If your electrical system isn't grounded correctly, you'll be turning away paying customers with no explanation that makes sense to them. Test your pedestals now. Fix what's broken before peak season gets any deeper.
Sources: RVIA / Electrical Works / RV News