A Deep Dive Into Interoperability Testing for Residential Fans with Advanced Function Circuit Breakers
While the number of residential fires has been significantly reduced over the last 20 years, the National Fire Protection Association reports more than 45,000 fires related to electrical failure or malfunction every year.1 The way homes and furniture are built these days provides for faster flashover, meaning the time to escape these fires has dropped from 17 minutes to 4 minutes over 30 years.2 This indicates a critical need to provide solutions to prevent these fires and the loss of life and property.
The growth in locations requiring electrical protection in homes using advanced function circuit breakers, as required within the National Electrical Code®, has prompted some to ask whether these breakers will function during a hazardous condition but not work during standard operating conditions. To test this, we chose a popular category of residential devices – fans used for ventilation and exhausting.
Per the Business Research Company, the residential fan market alone has grown steadily in recent years and is expected to grow from $9.94 billion in 2023 to $10.35 billion in 2024.3
The types of residential fans reviewed during testing include attic ventilation, bathroom exhaust, and radon gas removal fans. An advanced function circuit breaker is defined as an arc-fault circuit interrupter (AFCI), ground-fault circuit interrupter (GFCI), or a dual function (DF) circuit breaker that incorporates both technologies. All advanced function circuit breakers also provide thermal magnetic circuit breaker protection.
Interoperability Test Program
A test program was developed and completed to determine any concerns about the interoperability of residential fans with advanced function circuit breakers. The test protocol used leakage current monitoring to determine if the DF circuit breaker tripped on arc fault, ground fault, or thermal magnetic. A variety of manufacturers and types of fans were evaluated. Three manufacturers of DF advanced function circuit breakers were utilized for the testing. The testing utilized a humidity chamber to provide a realistic environment for various humidity and temperature levels.
The large ESPEC humidity chamber was set at 54° (130°F) to conduct the test for the attic fans. The test was conducted for two days for each circuit breaker on fans from multiple attic fan manufacturers. The bathroom and radon fan tests were completed with the humidity chamber conditions cycled between 20% to 93% every three hours. The humidity, temperature, and speed change were evaluated for each DF circuit breaker over a period of two days. The bathroom fans consisted of a mix of standard exhaust fans, and those with accessories such as lights and humidity sensors. There were also three fans which utilized electronically commutated motors (ECMs) that allowed for multiple speeds.
Figure 1 Laboratory equipment and testing courtesy of Schneider Electric
Conclusion
There were five different attic ventilation fans from five different manufacturers, 11 bathroom fans from six different manufacturers, and five radon fans. No dual function circuit breaker tripped during any of the tests. These results confirmed that AFCI, GFCI, and thermal magnetic protection functions within advanced function circuit breakers continued to operate without tripping, demonstrating interoperability with attic, bathroom, and radon fans. This data was submitted to the NEC® Code Making Panel 2 in support of adding AFCI protection to attics and bathrooms into the 2026 NEC.
The testing cited above was performed over an 8-week period in 2023 by Schneider Electric at its Cedar Rapids, IA test laboratory. Products from members of NEMA’s AFCI Promotional Task Force were used in device testing in a controlled environment.
Contact: Keith Waters, P.E.
Schneider Electric
keith.waters@se.com
References
1 Home Electrical Fires, NFPA Report, January 31, 2022, https://www.nfpa.org/education-and-research/research/nfpa-research/fire-statistical-reports/electrical-fires
2 UL’s Fire Safety Research Institute, New Comparison of Natural and Synthetic Home Furnishings, September 30, 2020, https://technicalpanels.fsri.org/research-projects/comparison-of-synthetic-and-natural-home-furnishings.html
3 Global Ceiling Fans Market Report, January 2024, https://www.thebusinessresearchcompany.com/report/ceiling-fans-global-market-report#:~:text=The%20ceiling%20fans%20are%20applied,through%20online%20and%20offline%20channels.&text=The%20ceiling%20fans%20market%20size,(CAGR)%20of%204.1%25