Arc Fault Circuit Interrupters and Home Appliances


Prepared by:

NEMA Low Voltage Distribution Equipment Section

National Electrical Manufacturers Association

1300 North 17th Street, Suite 900

Rosslyn, Virginia 22209

 

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Introduction

Arc-fault circuit interrupters (AFCI) were introduced into the National Electrical Code® (NEC) in 1999 for single-phase 15A and 20A branch circuits serving bedroom branch circuit outlet receptacles to provide protection from arcing faults that can cause fires. The introduction of this technology was driven by the Consumer Product Safety Commission (CPSC) and the Electronic Industries Association (EIA) in response to concerns that the conventional circuit breaker was not providing protection of branch circuit arcing, resulting in home electrical fires and deaths, injuries, and property loss.

AFCIs undergo rigorous testing, and in addition to the product standards (circuit breaker) to which each device is listed, they are also listed to UL 1699 Arc-Fault Circuit-Interrupters. The NEC, which is adopted in all 50 states throughout the U.S., is updated on a three-year revision cycle through a consensus-based development process. Subsequent NEC editions since the 1999 NEC have increased the number of locations where AFCIs are required. It was the 2014 edition of the NEC that added kitchens and laundries, where many cord and plug connected appliances are used on 120V single-phase 15A and 20A circuits.

This paper discusses the 15A and 20A AFCI protection of branch circuits that are utilized by cord and plug connected appliances and will provide perspective on the breadth of appliances currently protected by AFCIs. This will include a review of the number and types of appliances that are being protected along with how that data is determined. A review of the testing procedures and types of appliances tested will also be detailed in this document along with the number of test cases. Finally, a 2022 electrical contractor survey conducted by the Electrical Safety Foundation International (ESFI) on AFCI- and GFCI-protected circuits in the Commonwealth of Massachusetts will be presented [1]. The details of the ESFI research results will be addressed as they pertain to the topic of this paper.

Appliance Installations

The National Association of Home Builders (NAHB) publishes the number of 1- to 2-family homes and multi-family units built within the U.S. on a state-by-state basis. According to NAHB data, there were over 11 million dwelling units built since 2014. Over 9.5 million of those dwelling units were built in states where a majority of cord/plug appliances are protected by AFCIs.

Review of this data, coupled with the percentage of various appliances per home as found via a Statista November 2022 survey report [2], reveals that over 60 million appliances are protected by AFCIs. This is a very conservative number, as it does not include older homes that have been upgraded during the period of 2014 through 2022. Examples of the percentage of homes containing specific appliances are dishwashers (56%), refrigerators (83%), microwaves (84%), vacuums (76%), and washing machines (74%).

Unwanted Tripping

Unwanted tripping can manifest itself for many reasons that could include identification of wiring problems or lack of compatibility with a connected load. The American Circuit Breaker Manufacturers Association (ACBMA) reports [3] that received calls on AFCIs tripping is at 0.0078% of AFCIs shipped. These reports collect data that includes questions on selection, wiring, application, and tripping. Reports have revealed that tripping incidents are split between overload/short circuit and arc fault, with a large majority being overload/short circuit. In reviewing this research data and comparing this data to the number of appliances that are reported to trip AFCIs, it is found that claims and statements made related to compatibility being the vast majority of AFCI unwanted tripping incidents are not substantiated.

NEMA received 35 reports of unwanted tripping through the AFCIsafety.org website in 2021 through 2022, and none of the reported unwanted tripping issues identified a faulty circuit breaker or an incompatible product issue. There are, however, 10 submissions where the customer has not responded to the investigation. It would be fair to question why the actual documentation of reported AFCI tripping concerns does not match that which is claimed by certain industry groups.

One of the reasons AFCI technology has performed and continues to perform well is because of the partnerships between AFCI manufacturers and their customers, who together are able to identify applications and practical application examples that facilitate AFCI manufacturer interoperability tests with a variety of appliances and appliance combinations. These home appliance lab emulations conduct over 130,000 test cases covering over 400 appliance brands and 150 product types. There is also an additional testing done for over 40,000 combination loads such as various countertop appliances, vacuum cleaners, power tools, and durable medical equipment. The lab tests use loading, temperature, humidity, and other factors to change the parameters to provide as many options as possible to determine if an AFCI will trip when protecting the circuit where an appliance or group of appliances is installed. The results of these extensive tests are AFCIs that function properly with appliances.

 

Figure 1 Courtesy of Schneider Electric

Figure 2 Courtesy of Schneider Electric

 

ESFI Electrical Contractor Survey

The Electrical Safety Foundation International (ESFI) conducted a survey of electrical contractors asking about how AFCI and GFCI devices performed in homes in Massachusetts. The Commonwealth of Massachusetts has had a requirement for all 120VAC 15A-20A receptacles to be protected by AFCIs since January 1, 2020. The respondents stated that they make an average of 27 total service calls per week. The contractors concluded that 59% of these calls were related to tripped circuit breakers or fuses. In reviewing the responses on circuit breaker calls, the breakdown of results includes the following:.

  • 68% of the service calls were related to overload/short circuit trips
  • 18% of the service calls were AFCI trips
  • 10% of the service calls were GFCI trips
  • 4% of the service calls were defective products

Further investigation of the results of the service calls found that the most common mistakes identified by electrical contractors included the following:

  • 37% were wiring issues
  • 32% were related to the lack of or inadequate GFCI protection
  • 27% overloaded circuits
  • 2% other causes

There were no documented issues related to AFCIs from what was found on these service calls. ESFI also attempted to survey homeowners who live in homes built since January 1, 2020, but did not receive statistically significant results. The initial findings showed that AFCI devices work as designed to detect faults in appliances and wiring, but more research is required..

Summary

In conclusion, data shows that AFCIs are protecting over 60 million appliances with a very small number of documented reports of unwanted tripping. The claims around high amounts and percentages of unwanted tripping have been anecdotal; lack details on when, where, and why occurrences are happening; and do not constitute facts around AFCI and appliance compatibility performance. These are clearly unsubstantiated statements in light of the data provided in this document.The amount of testing done to verify that AFCIs will work with various appliances is extensive and goes far beyond what the product safety standard requires to make sure homeowners receive the best protection from fires with the installation of AFCIs. In addition, the ESFI survey shows that most tripping reports and issues are overloads and short circuits. The absence of any AFCI reported unwanted tripping issues from a state that requires them to protect most, if not all, of the receptacles found in the house provides further data that AFCIs are functioning properly. This data provides specific information on the successful safety protection of branch circuits by AFCIs when loads are appliances or other devices..

References

[1] ESFI Arc-Fault Circuit Interrupter (AFCI) and Ground Fault Circuit Interrupter (GFCI) Performance Survey, ESFI, 2022

[2] Household appliances ownership in the U.S. in 2022, Alexander Kunst, Statista, 2022

[3] NEC® CMP-2 ACBMA Presentation, American Circuit Breaker Manufacturing Association (ACBMA), October 2018[/vc_column_text]