GFCI Nuisance Tripping on HVAC
An exception delaying GFCI protection for listed HVAC equipment was carried through the 2020 and 2023 NEC cycles specifically because of this incompatibility, and finally expires September 1, 2026.
Why standard GFCIs and modern HVAC don't always get along
Older HVAC equipment ran simple fixed-speed motors with minimal leakage current. Newer variable-speed and inverter-driven units use internal power electronics that can generate small, high-frequency leakage currents that a standard Class A GFCI reads as a fault, even though it isn't the kind of fault that threatens a person.
The fix: matching the device to the equipment
Special Purpose GFCIs (Class C SPGFCI), including HF-rated versions, are now recognized specifically for this equipment. If nuisance tripping started right after a new HVAC, pool, or spa installation, the fix usually isn't removing protection — it's swapping to a device class built for that equipment's leakage profile.