Overcurrent Protection News

Submitted by Mike Miller, Curriculum & Training Manager

Increased information is becoming available about the 2026 National Electrical Code, and I believe you will be interested to know about some of the newer overcurrent protective devices that are making their way into the code to improve protection.

It is hard to forget the challenge we faced relating GFCI protection for air conditioning equipment when the 2020 NEC, in Article 210.8(F), required this protection on all outdoor outlets of which A/C systems were part of. Finally, before the 2023 code was published, a Temporary Interim Amendment 23-3 was published and put into effect on September 1st  that stated: “GFCI protection shall not be required for listed HVAC equipment. This exception shall expire September 1, 2026.’ Dean Hunter, from Minnesota DOLI, was instrumental in researching issues that installers were having keeping certain air conditioners operating because of their industry – permitted current leakage.

His and the study group’s efforts  made a significant impact on resolving this problem which is ongoing.

A Class A GFCI circuit breaker required by NEC based on UL standard 943, would trip at 6 mA. A/C systems that employed an adjustable speed drive would routinely exceed the 6 mA threshold of the breaker. In some cases, installers were left with the choice of replacing GFCI protection with a standard inverse time breaker and being out of compliance or having angry customers because their air conditioning system was inoperable.

Exception No.2,  Article 210.8(F) of the 2023 NEC left in place the expiration date of September 1, 2026 for the “No GFCI protection required for listed A/C units”. However, in the 2026 NEC, a new Exception No. 3 was added that states:

Exception No. 3: Listed Class C SPGFCI protection shall be permitted for listed HVAC equipment. If a Class C SPGFCI is provided, the disconnect serving the HVAC equipment shall be marked “Warning: Class C SPGFCI Protection Provided for HVAC Unit.”

An informational Note was also added that states:

“Informational Note: See UL 943C, Outline of Investigation for Special Purpose Ground-Fault Circuit-Interrupters, for further information. SPGFCIs marked “HF,” or “HF+” do not trip when the frequency weighted differential current is less than the specified value for a Class C, Class D, or Class E SPGFCI”

So, what is this HF breaker?

"HF" in the context of circuit breakers, specifically Ground Fault Circuit Interrupters (GFCIs), refers to a standard for devices designed to enhance both safety and interoperability. These breakers, often designated as "HF GFCI" devices, are built to trip faster and more consistently in response to high-frequency leakage currents, addressing a gap in the protection offered by older GFCI designs. This means they provide a more robust defense against electrical shock, particularly in the presence of potentially dangerous leakage currents associated with electronic devices.

The term "HF+",  in the context of circuit breakers, primarily refers to a proposed enhancement to existing circuit breaker standards, specifically for Ground Fault Circuit Interrupters (GFCIs) operating in high-frequency applications. 

This enhancement aims to address the challenges posed by high-frequency currents, increasingly present in homes and businesses due to devices like: 

• Variable Frequency Drives (VFDs) in HVAC and pool equipment.
• Electric vehicle charging infrastructure. 

Are they available?

Eaton is currently leading the charge with HF+ GFCI breakers, and their white paper suggests they are already manufacturing and distributing them. However, most other U.S. manufacturers have not yet adopted HF or HF+ as a stocked standard across their product lines. It is still in the early adoption phase, and availability may vary by distributor or region. I must comment that this information was current as of the end of July and is subject to change.

There are a substantial number of changes to look forward to in the 2026 NEC. Consider attending our classes to find out more.