Time is running short for the HVAC industry as the September 1, 2026 expiration of the ground-fault circuit-interrupter (GFCI) protection exception. The exception currently allows listed outdoor HVAC equipment to operate without Class A GFCI while the industry works to resolve longstanding interoperability and unwanted-nuisance tripping concerns.
The Air-Conditioning, Heating, and Refrigeration Institute (AHRI) has submitted proposed Tentative Interim Amendments (TIAs) for the 2020, 2023, and 2026 editions of the NEC to extend the expiration date until September 1, 2028. NFPA has placed the proposals into the public-comment process, with comments due September 9, 2026.
ACCA has submitted public comments supporting the AHRI TIA. ACCA believes the requested two-year extension is a limited and reasonable step that will allow the industry to complete the laboratory evaluation and field validation needed to demonstrate reliable compatibility across the full range of listed HVAC equipment covered by NEC 210.8(F).
Where’s the proof?
ACCA recognizes that important progress has occurred since the current exception was established in 2022. “High-frequency” (HF) GFCI devices have been developed and listed, and manufacturers continue to work on products intended to reduce unwanted tripping. But product development and listing alone fail to demonstrate that the interoperability problem has been resolved across the installed population of HVAC equipment.
That distinction is central to ACCA’s public comments. The 2022 NFPA GFCI Task Group documented nuisance tripping involving not only inverter-driven equipment, but also conventional single-stage equipment. The Task Group identified unresolved HVAC-specific problems that could shut down equipment operation. These include compressor starting, electrical distortion during startup, refrigeration-system pressure differential, wide outdoor operating-temperature ranges, high-frequency current effects, and the increasing use of power-conversion equipment and ECM motors. NFPA procedures require technical reasons and test data must be provided to prove these obstacles have been overcome and system operation is unaffected by poorly performing GFCI products.
ACCA’s comments emphasize that the current exception applies to listed HVAC equipment generally and not only variable-speed or inverter-driven systems. Before that exception expires, the technical record should demonstrate that the requirement can be applied reliably across the equipment population it will affect.
AHRI testing raises additional questions
AHRI’s recently completed research provides important new technical information. As highlighted in ACCA’s public comments, AHRI’s test results show that five of twelve GFCIs tested tripped below the applicable must-hold current above 60 Hz. That finding indicates that HVAC leakage current below the must-hold curve can still result in trips that HF GFCI technology was intended to reduce.
The issue is important because it is not whether an HF-marked GFCI exists. The issue is the lack of demonstrated reliable compatibility across the GFCI-equipment combinations contractors will encounter. AHRI’s research shows evidence this technology is not yet ready for mass implementation.
Loss of cooling is also a life-safety issue
Electrical shock protection is unquestionably a life-safety objective. But the discussion cannot ignore the potential consequences when unwanted GFCI tripping disables air conditioning during extreme heat.
2024 data from the Maricopa County Department of Public Health. The county recorded 138 indoor heat-related deaths. Air conditioning was present in 88 percent of those cases; among those cases, the air-conditioning system was not functioning in 70 percent and was not in use in another 18 percent.
These figures, from just one county in only one state underscore why reliable HVAC operation is more than a comfort issue. Older adults, people convalescing at home, and other vulnerable occupants may not be able to recognize a loss of cooling, locate and reset a tripped GFCI, diagnose the cause, or arrange immediate service. The question before NFPA is therefore not a choice between equipment reliability and safety. It requires balancing electrical safety with the very real life-safety consequences of unintended loss of cooling while the remaining interoperability questions are resolved.
LBA adds new market-readiness evidence
ACCA is not alone in urging additional time. On August 13, Leading Builders of America (LBA) submitted a filing asking the NFPA Standards Council to reconsider Decision #25-5 and extend the 210.8(F) exception to September 1, 2028. LBA’s filing adds a different but complementary dimension to the technical record: whether emerging products are actually available through normal distribution channels in the necessary panel families, amperages, and quantities before the current exception expires. LBA reported an uneven transition among major GFCI manufacturers, including products still moving through manufacturing and distribution and other HF products scheduled for sale or volume availability after September 1. The filing also argues that availability by itself does not establish effectiveness without transparent compatibility and field-performance data. That market evidence reinforces the need for a measured transition rather than assuming that the existence of a listed product means the interoperability issue has been fully resolved.
A two-year extension provides time to finish the job
The September 1, 2028 date requested by ACCA, AHRI, and LBA does not abandon GFCI protection or prejudge the ultimate technical solution. It extends an existing, temporary exception for a defined period so that HVAC manufacturers, GFCI manufacturers, testing laboratories, standards developers, contractors, inspectors, and other stakeholders can complete the work already underway.
That additional time can be used to expand laboratory and field validation, evaluate both inverter-driven and single-stage equipment, develop transparent compatibility information, allow new products to become routinely available through distribution, and address remaining interoperability problems before contractors and homeowners become the final test population.
ACCA fights on
ACCA will continue working with AHRI, LBA, manufacturers, contractors, code officials, and other industry allies to achieve a solution that protects people while allowing HVAC equipment to operate safely and reliably.
ACCA also encourages contractors with relevant field experience to contribute. Those who have experience with HF GFCIs, unwanted tripping, or successful installations, are invited to participate in the process and help ensure that the final decision is supported by real-world evidence. Contractors can make their voices heard by taking ACCA’s online poll here. Take the poll
ACCA is launching a resource page online to provide valuable resources to anticipate that some local or state jurisdictions may start requiring GFCI devices on HVAC equipment installations outdoors.
Stay tuned!
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