QUICK REFERENCE GUIDE
The National Electrical Code® (NEC®) requirements for ground-fault circuit-interrupter (GFCI) protection of outdoor HVAC equipment continue to evolve. ACCA is working with industry partners to address equipment compatibility, unwanted GFCI tripping, product availability, enforcement, and the potential life-safety consequences associated with loss of heating or cooling.
This FAQ is intended to help contractors, code officials, and other HVAC industry stakeholders understand NEC Section 210.8(F), determine whether it applies in their jurisdiction, understand high-frequency (HF) GFCI technology, and follow ongoing industry efforts.
Frequently Asked Questions
Start Here: Does the Requirement Apply to You?
Start with the code adopted in your state or local jurisdiction. The outdoor HVAC GFCI requirement first appeared in the 2020 NEC, but states and local jurisdictions have adopted, amended, delayed, or otherwise treated the requirement differently.
Use the state-by-state information linked from ACCA's GFCI Resource Center, including HARDI's outdoor HVAC GFCI map and NFPA's NEC adoption information. Always confirm the final requirement with the authority having jurisdiction (AHJ).
Yes, it can. NEC Section 210.8(F) applies to outdoor outlets supplied by single-phase branch circuits rated 150 volts to ground or less and 50 amperes or less. A typical 240-volt single-phase system is approximately 120 volts from either ungrounded conductor to ground, so the 150-volts-to-ground threshold does not mean that 240-volt HVAC equipment is automatically outside the requirement.
Section 210.8(F) addresses outdoor outlets. Other NEC GFCI provisions may apply to equipment or receptacles in locations such as basements or other areas for which the NEC separately requires GFCI protection.
Condensate pumps and indoor furnaces or air handlers should therefore be evaluated under the requirements applicable to their specific location, branch circuit, connection method, and the NEC edition adopted by the jurisdiction. Contractors should verify the applicable requirement with the AHJ.
Code adoption and amendment procedures vary by state and jurisdiction. ACCA's GFCI Resource Center will provide industry information and advocacy resources that contractors and state associations can use when participating in state or local code-adoption processes.
Understanding the Requirement
It requires GFCI protection for outdoor outlets supplied by single-phase branch circuits rated 150 volts to ground or less and 50 amperes or less. The requirement can apply to outdoor air-conditioning and heat-pump equipment.
Contractors should consult the NEC edition adopted in their jurisdiction, including state and local amendments, because requirements vary considerably across the country.
GFCIs provide important protection against electrical shock. The HVAC industry's concern is not with the value of GFCI protection itself, but with ensuring that GFCI devices and connected HVAC equipment operate together reliably.
HVAC equipment can produce leakage currents and electrical characteristics different from many conventional appliances. Field experience and industry testing have raised concerns that some HVAC equipment may cause unwanted GFCI trips even when an electrical fault requiring GFCI protection is not present.
An unwanted trip can shut down heating or cooling equipment without the occupant immediately realizing what has happened.
Loss of cooling during periods of extreme heat can create serious health and safety consequences, particularly for older adults and other vulnerable occupants.
ACCA has emphasized that electrical shock protection and the consequences of unintended HVAC shutdown both deserve consideration when evaluating the overall safety of the requirement. Research cited in ACCA's public comments demonstrates that failure or nonoperation of air-conditioning equipment can contribute to heat-related deaths.
HF GFCIs and HVAC Compatibility
“HF” refers to GFCI technology intended to better accommodate higher-frequency leakage currents associated with certain modern HVAC equipment, particularly equipment using inverter-driven components.
HF GFCIs listed to UL 943 have begun entering the marketplace. Their availability is an important development, but availability alone does not establish compatibility with every HVAC system.
That has not yet been demonstrated across the full range of HVAC equipment. One important distinction is between higher-frequency leakage associated with inverter-driven equipment and leakage occurring around the conventional 60 Hz power frequency.
Industry testing has raised concerns about GFCI operation with some HVAC equipment at or near 60 Hz. ACCA therefore supports additional testing and technical proof that the devices operate reliably with the range of HVAC equipment encountered in the field.
Potentially, yes. Variable-speed and inverter-driven equipment can generate higher-frequency electrical leakage characteristics that differ from conventional single-stage 60 Hz equipment.
At the same time, some nominally single-stage equipment uses variable-speed outdoor fan motors or other electronic components that can introduce frequency-related leakage characteristics. Equipment labels alone may therefore not tell the entire compatibility story.
Not reliably. Product labels and listings can provide important information, but sufficient field testing has not yet demonstrated that every combination of HVAC equipment and GFCI will operate consistently without unwanted tripping.
Equipment design, controls, motors, drives, wiring, installation conditions, and the characteristics of the GFCI itself can all affect system performance. Code compliance should not be confused with demonstrated compatibility between every possible combination of HVAC equipment and GFCI device.
For Contractors Who Must Comply
Follow the adopted code, equipment-manufacturer instructions, product listings, and AHJ requirements. Required electrical safety protection should not be bypassed or disabled simply to keep equipment operating.
A GFCI trip should never automatically be treated as a nuisance. First determine whether an actual ground fault, wiring problem, equipment defect, installation issue, or other unsafe condition exists.
If those conditions have been eliminated and unwanted tripping continues, consult the HVAC equipment manufacturer and GFCI manufacturer regarding compatibility, installation requirements, and approved corrective measures.
ACCA also wants field feedback on unwanted HVAC GFCI trips. Contractors should report relevant field experience through the ACCA reporting mechanism linked from the GFCI Resource Center.
Report the event after normal troubleshooting has ruled out an actual ground fault, wiring defect, equipment defect, or installation problem and the evidence points to unwanted GFCI operation or a compatibility issue.
Useful reports should identify, when available, the HVAC equipment type and model, the GFCI manufacturer and model, whether the equipment is conventional or inverter-driven, the circumstances of the trip, and the troubleshooting performed. Field reports will help ACCA and industry partners identify patterns that warrant further investigation.
Where Things Stand
The NEC exception affecting certain listed HVAC equipment was scheduled to expire September 1, 2026. Because code adoption and the NFPA amendment process can change the practical effect of that date, contractors should use the ACCA GFCI Resource Center and verify the requirement currently enforced by their AHJ rather than relying on the original sunset date alone.
The Air-Conditioning, Heating, and Refrigeration Institute (AHRI) submitted a Tentative Interim Amendment (TIA) asking NFPA to extend the expiration date of the HVAC exception from September 1, 2026, to September 1, 2028.
ACCA submitted public comments supporting the requested extension. ACCA believes additional time is warranted because questions remain concerning compatibility between GFCIs and certain HVAC equipment, particularly conventional 60 Hz equipment, and because unwanted GFCI operation can itself create safety consequences when heating or cooling is interrupted.
The requested extension is intended to provide additional time for testing, technical evaluation, field data, and product development.
If NFPA approves the amendment as proposed, the expiration of the applicable HVAC exception would move to September 1, 2028. Contractors would still need to verify how the change applies under the NEC edition and amendments adopted in their jurisdiction.
Where the adopted code requires GFCI protection for the HVAC equipment and no applicable exception or local amendment applies, contractors must comply. Verify local requirements with the AHJ and follow ACCA updates as the NFPA process continues.
Yes. Leading Builders of America (LBA) has pursued procedural action before the NFPA Standards Council concerning the treatment and timing of the outdoor HVAC GFCI requirements.
That activity is separate from, but related to, the technical issues being considered through AHRI's proposed amendment process. ACCA continues to monitor both developments.
State-by-State Requirements and Resources
No. Requirements vary depending upon the NEC edition adopted by the state or local jurisdiction. Some jurisdictions have modified or delayed application of the requirement; others operate under older NEC editions that do not contain Section 210.8(F); and some enforce NEC editions containing the requirement.
HARDI maintains a state-by-state resource and map identifying jurisdictions where outdoor HVAC GFCI requirements apply, have been modified, or have been delayed. NFPA also provides information on NEC adoption and enforcement by state. ACCA's GFCI Resource Center will link to both resources.
Contractors should always verify current requirements with their local AHJ because state and local code adoption can change.
ACCA will continue updating its GFCI Resource Center as additional information becomes available, including the AHRI TIA, NFPA Standards Council action, ACCA public comments and advocacy, GFCI/HVAC compatibility, HF GFCI technology, testing and field experience, and state and local code developments.
Important: This information is provided as a general industry resource and is not a substitute for the adopted electrical code, equipment manufacturer's instructions, product listings, or determinations of the authority having jurisdiction.