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This article describes how to install AFCIs & how to test AFCIs. We also explain the difference between an arc fault circuit interrupter (AFCI) and a ground fault circuit interrupter.
The article also describes AFCI Recall in 2004 & provides a Square-D & Federal Pioneer AFCI Notice. Here are tips for wiring & using AFCI's for arc fault protection to help reduce fire risk in homes.
This article series, adapted and expanded from a US CPSC article on AFCIs is supplemented with additional details and commentary answers most home owner and home inspector questions about installing, testing, and inspecting AFCIs - arc fault protectors in homes.
InspectAPedia tolerates no conflicts of interest. We have no relationship with advertisers, products, or services discussed at this website.
- Daniel Friedman, Publisher/Editor/Author - See WHO ARE WE?
2004 Square D AFCI - Arc Fault Circuit Breaker Recall
In 2004 Schneider Electric issued a recall of early model Square D® AFCIs manufactured between March 1 2004 and September 23, 2004 because tests indicated that "... arc detection in these breakers may become inoperable due to an issue with a third party-supplied internal component in the electronic detection unit."
Schneider's letter emphasized in an opening statement that "... Square D Company, the leading manufacturer of electrical equipment, is committed to the safety of our people, our customers, and our products." The company's letter provided additional detail:
While these circuit breakers will continue to function normally, providing short-circuit and overload protection, a small percentage of the breakers may not function as an arc fault circuit breaker (AFCI) and detect a high-resistance low-current arc fault.
The unique role of an AFCI is its ability to detect an electrical arc and shut down a circuit before a fire can start or spread. It is important to note that the affected circuit breaker itself does not pose a hazard.
[The company was concerned about inaccurate and misleading information in the electrical products market and asked that concerned parties turn to them for information regarding their products, including AFCIs.]
The issue with the component has been corrected and we have significantly increased our manufacturing capacity of AFCI breakers, allowing us to replenish our distribution network as quickly as possible. We are shipping significant quantities of AFCI circuit breakers from our manufacturing facilities every day.
[intervening paragraphs addressing the ramp-up of production are here omitted as now obsolete-DF]
We are also initiating a program to recover product that has been installed during this timeframe and replacing affected breakers with newly manufactured AFCIs.
We are working directly with electricians, homebuilders and homeowners to inspect and replace affected breakers. the nationwide effort is being managed by us directly with our customers. There is no specific action you need to take in this recovery program other than help us make sure everyone has accurate information.
The positive responses we have received from electrical inspectors regarding our honest and direct approach to resolving this issue have been appreciated. Many inspectors have been working actively with us as well as their local electrical contractors and builders to minimize the disruption in the construction process.
Those combined efforts have been successful at a vast number of localities.
[...]
We believe that we can accept nothing less than excellence when it comes to safety. For more than 100 years, our customers have associated the Square D brand with industry leadership, safety, quality, and reliability. We intend that our efforts through this AFCI program will continue those qualities.
2004 Square D AFI, QO & HOM Circuit Breaker Recall Details
[Minor editing for clarity performed by InspectApedia.com 2021/02/13 - Ed.]
This recall is only for Blue Push Button AFI, QO, and HOM breakers in a Specific date range from March 2004 to the beginning of October 2004 (see this 2004 Schneider Square-D AFI RECALL BRCOHURE [PDF] for complete details). If the push buttons are of a different color this recall does not apply.
Date Code is indicated by a RED 2 letter stamp located on the Sticker "made in Mexico" (White) at the bottom of the breaker where the Black Circuit wire is connected to the breaker.
If the breaker is part of the recall then the white sticker will have one of the following codes: CN, DN, EN, FN, GN, HN, JN, (If code is not legible – we will assume it is affected and it should be replaced).
If it is another combination of letters, then the breaker is not under recall.
Homeowner Actions
If your home has affected breakers your next step is to contact an electrician that is familiar with the square D Recall.
The electrician should not charge you for material as he can take the affected breakers, or any breaker that has a Blue Push Button and you cannot read the Letter Code, to a SQD / Schneider Electric distributor or Box Store. They will swap the breakers, so there is no cost to you for the new breaker. The distributor/Box store can return the affected breakers to square D /Schneider Electric for credit.
The
electrician should only charge you for his labor.
For reimbursement Please Submit the Following:
Claim Form: Completed this ATTACHMENT 2 [.doc file] or print and fill-in this identical PDF file ATTACHMENT 2 [PDF] (located in AFI Breaker- Homeowner information file)
Be sure to include your name, phone number, and email address
Electrician's Invoice: Copy of electrician’s invoice showing contractor was paid for Labor Only to inspect and
change out the breakers if necessary.
Note: If the breakers do not need changed then
we will still pay for the labor inspect.
Michelle Martin
National Process Team – Safety Alerts Toll Free 800.634.8730
8848 Red Oak Bl Suit
Charlotte, NC 282 United Sta
Schneider Electric Product Service Group
8848 Red Oak Boulevard (Suite A)
Charlotte, NC 28217
Attn: Michelle Martin
You can also send the CPSC email on incidents to: info@cpsc.gov
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Other InspectApedia.com suggestions
See FREEZE-PROOF A BUILDING where we describe GFCI protection on heat tape circuits powering heat tapes for manufactured and mobile homes.
At SUMP PUMP PROTECTION similar issues regarding building water entry control vs electrical safety & breaker tripping are discussed.
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In addition to any citations in the article above, a full list is available on request.
Dr. Jess Aronstein, protune@aol.com is a research consultant and an electrical engineer in Schenectady, NY. Dr. Aronstein provides forensic engineering services and independent laboratory testing for various agencies. Dr. Aronstein has published widely on and has designed and conducted tests on aluminum wiring failures, Federal Pacific Stab-Lok electrical equipment, and numerous electrical products and hazards.
Contact: J. AronsteinConsulting Engineer Bme, Msme, Ph.D., N.Y.S.. P.E. Lic. No. 39860, 909 Londonderry Ct., Schenectady, NY 12309 USA, Tel: (845) 462-6452 Email: AronsteinJesse@ieee.org
Steel, J. G., and D. T. Swift-Hook. "Statistics of circuit-breaker performance." Electrical Engineers, Proceedings of the Institution of 117, no. 7 (1970): 1337-1345.
Lai, M. L., S. Y. Park, C. C. Lin, H. Naidu, A. Soom, A. M. Reinhorn, Y. H. Lee et al. "Mechanical failure detection of circuit breakers." Power Delivery, IEEE Transactions on 3, no. 4 (1988): 1724-1731.
[1] AFCI Circuit Interrupters, US CPSC Publication www.cpsc.gov/CPSCPUB/PUBS/afcifac8.pdf, with extensive edits and additions by the website author. Original source cpsc.gov/CPSCPUB/PUBS/afcifac8.pdf
[2] Note 1 Ault, Singh, and Smith, “1996 Residential Fire Loss Estimates”, October 1998, U.S. Consumer Product Safety Commission, Directorate for Epidemiology and Health Sciences.
[3] Schneider Electric, North American Operating Division, 1415 South Roselle Road, Palatine IL 60067 16 December 2004 , Letter addressed to Dan J Friedman, from Jim Pauley, Vice President, Industry and Government Relations.
[4] Underwriters Laboratories (UL) describes the the types of AFCIs and the types of tests performed on AFCIs at www.ul.com/regulators/afci/AFCI_scenarios020502.pdf. Also, UL 1699, “Standard for Arc-Fault Circuit Interrupters” at the UL website provides more detailed information on the differences between the older AFCI's and the new combination type devices.
[5] Nuisance tripping of AFCI's is described in detail, along with other details about AFCIs in an online article, "Arc Fault Detection: your questions answered", ecmweb.com, August 2008.
[6] Mike Holt, in our opinion the leading writer about electrical wiring and devices, has a nice article about AFCIs at https://www.mikeholt.com/mojonewsarchive/AFCI-HTML/HTML/Arc_Fault_Protection~20020124.htm Mr. Holt discusses current electrical code requirements for GFCIs (Ground Fault Circuit Interrupters) at http://ecmweb.com/mag/electric_branch_circuits_part_2/.
[7] Testing of AFCIs using external devices (not the test button): see article by Underwriter's Laboratories (UL) March 21, 2005 at https://www.ul.com/tca/winter05/news.html and this comment by Ryan Jackson at Mike Holt's website: (a reply from Jim Gregorec,
Group Manager - T&M Division, Ideal Industries posted at the website takes a different view which is also posted there)
[8] To paraphrase the article, there is no such thing as an AFCI tester, other than the test button that is an integral part of the AFCI device itself. The reason for this is that an AFCI device is very complex, and recognizes the actual waveform of an arcing fault. While the advertised "AFCI Testers" do produce a waveform similar to that of an arc fault, they cannot produce an actual arc fault. Because of this, the "tester" may not trip the AFCI circuit breaker, despite the breaker having nothing wrong with it. For this reason, UL classifies these devices not as "testers", but as "indicators", which is much more accurate.
[8] These devices are tested under the UL 1436 standard, and are required to have included in the instructions the following clause (or equivalent):
"CAUTION: AFCIs recognize characteristics unique to arcing, and AFCI indicators produce characteristics that mimic some forms of arcing. Because of this the indicator may give a false indication that the AFCI is not functioning properly. If this occurs, recheck the operation of the AFCI using the test and reset buttons. The AFCI button test function will demonstrate proper operation."
[10] While these indicators may have some value for convenience to determine if the outlet in question is on an AFCI protected circuit, they are not to be substituted for the test button of the AFCI circuit breaker, and they are not an AFCI tester.
[13] GE, General Electric Corporation, General Electric Company,
41 Woodford Ave., Plainville, CT 06062, one of the companies producing AFCIs, provides wiring diagrams and installation instructions for their product. See GE's DEH-40117R4.pdf for detailed installation instructions from GE for the wiring of a typical AFCI on a simple 120V home electrical circuit.
[14] The Minnesota Electrical Association has posted an article of the most important electrical code changes for 2008 at http://www.electricalassociation.com/catalog/2008NECTop10.aspx - by Michael J. Johnston, IAEI
[15] "HUD Regulation for Manufactured Homes; Requirement that Heat-Tape not include a GFCI [ copy on file as /plumbing/GFCI_Heat_Tapes_HUD_CPSC_Letter1994.pdf ] - ", Meeting Log, US CPSC, HUD, Dennis McCoskrie, ESEE, 2/14/1994
[16] Personal communication, [electrician P prefers to remain anonymous], to DJF, 1/29/2012.
[17] Joseph Engel, "Ground Fault / Arc Fault Circuit Interrupter and Method of Testing the Same with a Test Button and a Resest Button", Patent No. 6,720,872 B1, Apr. 13, 2004. [copy on file as AFCI Patent US6720872.pdf and as AFCI_Patent_History.pdf]
[18] Engel, J.C., "Combination AFCIs: What they will and will not do", Electrical Safety Workshop (ESW), 2012 IEEE IAS, Jan. 31 2012-Feb. 3 2012, pp. 1 - 18,
Conference Publications, 9 March 2012, INSPEC Accession Number: 12578656. Mail: Joseph C Engel, PhD,
Member, IEEE,
107 Overlook Circle,
Monroeville PA 15146
USA, Email: josephengel1013@gmail.com Abstract: All new home branch circuits are required by Code to be electronically protected, either by Ground Fault Circuit Interrupters (GFCIs) or Arc Fault Circuit Interrupters (AFCIs). Areas including kitchens, bathrooms, garages, etc. must be protected by GFCIs, while living areas must be protected by AFCIs. The AFCI is the fourth generation in residential branch circuit protection after fuses, circuit breakers, and GFCIs. National Electrical Code in 2002 first added AFCI protection, for bedrooms outlets. In 2008, coverage was expanded to all living areas, also adding that only “Combination AFCIs” are allowed. Manufacturers and UL claim that arcing across a break in a cord's conductor is hazardous, and that a Combination AFCI will respond to prevent a fire. The author believes the claim is unproven, and will explain why the disallowed Branch/feeder AFCI provides more protection at less cost. Dr. Engel provides this link for a downloadable copy of this paper: http://www.combinationafci.com/
[18b] Engel, J.C., Aronstein, J., & Friedfman, Daniel J, personal correspondence 2/8/2013.
[19] Wafer, J.A., "The evolution of arc fault circuit interrupters", Electrical Contacts, 2005. Proceedings of the Fifty-First IEEE Holm Conference,
26-28 Sept. 2005, Eaton Corp., Pittsburgh,pp. 156 - 161 Abstract:
Traditionally, circuit breakers and fuses have provided overcurrent and short circuit protection in electrical distribution applications. Despite this protection, approximately 70,000 residential fires with more than 500 deaths and in property damage occur each year in the U.S. that are attributed to electrical initiation. When investigated it was found that in some cases the circuit breaker had not tripped. Arc fault circuit interrupters can recognize the unique signatures of arcing faults and initiate a trip condition to isolate and de-energize the arcing fault. This paper identifies the conditions that can lead to fire hazards. These include arcs to ground, wiring failure modes, earth leakage conditions and high resistance faults such as glowing contacts, and in-line low current arcs (sometimes referred to as series arcs).
[20] Douglas A. Lee,
Andrew M. Trotta,
William H. King Jr., "New Technology for Preventing Residential Electrical Fires: Arc-Fault Circuit Interrupters (AFCIs)",
Fire Technology
August 2000, Volume 36, Issue 3, pp 145-162, Abstract:
A new generation of residential electrical branch circuit breakers that incorporates technology to detect and mitigate the effects of arcing faults is described. Fire loss estimates attributed to electrical wiring and the development of the arc-fault circuit interrupter for the prevention of residential electrical fires are discussed. The industry voluntary standard for arc-fault circuit interrupters as well as the 1999 National Electrical Code requirement are reviewed.
[21] Shea, J.J., "Conditions for series arcing phenomena in PVC wiring", Electrical Contacts, 2005. Proceedings of the Fifty-First IEEE Holm Conference on
Date of Conference: 26-28 Sept. 2005, Eaton Corp., pp: 167 - 175 Abstract
Under certain circumstances, unintentional series arcing, caused from damaged line cords and loose connections, can pose a serious fire and safety hazard. This work, focusing on residential 115 Vac applications, shows how continuous bursts of ignited gases can be created from overheated PVC insulation created from glowing contacts with subsequent series arcing, or surface breakdown with subsequent series arcing. Also, surprisingly, these potentially hazardous fire conditions were created with currents as low as 0.9 Arms, at 115 Vac (100 W lamp load). Little research is available about the interaction of glowing contacts, formed from loose or broken copper conductors in wiring (outlets, switches, line conductors, etc.), with electrical insulation. This work shows how glowing contacts and surface arcing can decompose PVC insulation, form ignitable gases, and that it is possible for the subsequent series arc to ignite, and burn insulation. Two conditions are identified that can create an overheated connection - a glowing contact and/or breakdown over a charred insulation surface. Mechanisms are discussed along with data for glowing contact voltage drop, photographs of glowing connections, and a gas chromatograph analysis of the evolved gases emitted from overheated PVC wiring. Selected high-speed video frames (1000 fps) taken from videos of the series arc and bursts of ignitable gasses along with synchronized current and voltage waveforms over a current range of 0.9 Arms to 5 Arms are presented. These findings are useful for advancing the state-of-the-art in fire protection by providing a better understanding of how electrical fires can initiate.
[22] Restrepo, C.E., "Arc Fault Detection and Discrimination Methods", Electrical contacts - 2007, the 53rd ieee holm conference, 16-19 Sept. 2007, pp. 115 - 122 , Siemens Energy & Autom., Norcross, Abstract: Arc waveform characteristics can be evaluated with various methods to recognize the presence of hazardous arc fault conditions. Discussion covers the arc phenomena and how it is generated in a low voltage electrical distribution circuit, as well as the isolation of the presence of hazardous conditions versus conditions that could falsely mimic the presence of an arc fault. Many waveform characteristics and conditions support the detection of hazardous arc faults and foster a more robust design, capable of withstanding unwanted tripping conditions.
[23] Parise, G., "Arc-fault protection of branch circuits, cords and connected equipment" Industrial and Commercial Power Systems, 2003. 2003 IEEE Technical Conference, 4-8 May 2003,
Dipt. di Energia Elettrica, Rome Univ., Italy
Martirano, L. ; Nabours, R.E., pp: 85 - 88, Abstract: In electrical power systems, the fault frequently involves arcing and burning for all the wiring exposed to mechanical damage and other insulation stresses including wiring not fixed and connected by flexible cords and cables. The IEC Standard 60364 stops the design of electric power systems at the outlets of branch circuits or at the fixed equipment. A complete design instead should take care of the connections of the portable equipment and of extension cords (as requested by NFPA 70) that are exposed to arc-faults and may cause fire and/or electric shock hazard. The cords supplying the Class II equipment are without a grounding protection conductor, so the failure of the double insulation, caused by external damage, can't be expected to be easily detected as a ground fault. A protection must be provided to prevent the fault from extinguishing itself without being detected and remaining energized, thus presenting an electric shock hazard by direct contact with a live part, rendered accessible after local insulation failure. The authors highlight this worst case and suggest the protection achieved by wiring the circuits, particularly extension cords, with special power cables. Ground-fault-forced cables, GFFCs convert a line-to-line fault into a line to ground fault, that will be detected and protected by ordinary ground fault protective devices (GFPDs). By adopting the GFFC type of cables internally to Class II equipment, the disconnecting supplying measure could be extended to equipment also.
[24] Gregory, G.D., "More about arc-fault circuit interrupters" Industry Applications Conference, 2003. 38th IAS Annual Meeting. Conference Record, 12-16 Oct. 2003
Author(s): Gregory, G.D. Schneider Electr., Square D Co., Cedar Rapids, IA, USA, Kon Wong ; Dvorak, R.
Volume: 2, pp: 1306 - 1313 vol.2 Abstract: Since the arc-fault circuit interrupter (AFCI) was commercially introduced in 1998, questions have arisen about how it detect arcs, whether it detects series and parallel arcs, and what types of AFCIs are available. Types other than the original branch/feeder AFCI are emerging. This paper is intended to provide an update regarding answers to those questions, following an earlier paper that introduced the basic functioning of the AFCI (see G.D. Gregory et al., IEEE Trans. Ind. Apps., p. 928-33, 1998).
[25] Gammon, T., Matthews, J., "Instantaneous arcing-fault models developed for building system analysis", Industry Applications, IEEE Transactions on, Jan/Feb 2001, Volume: 37 , Issue: 1
Page(s): 197 - 203. Abstract:
An arcing fault is a dangerous form of short circuit that may have a low current magnitude. In the case of such faults, the magnitude of the current is limited by the resistance of the arc and may also be limited by the impedance of a ground path. This lower level fault current is often insufficient to immediately trip phase overcurrent devices, resulting in the escalation of the arcing fault, increased system damage, tremendous release of energy, and threat to human life. Despite modern advances in system protection and the adoption of National Electrical Code Section 230-95, people continue to be injured or killed from arcing faults, initiated by accidental physical contact or through a glow-to-arc transition. The initial phase of an arcing-fault research project was to review the historical evolution of arc modeling for low-voltage systems. A summary of the electrical aspects and the physics involved in arcing faults appeared in previous work. Today's better analytical tools facilitated the development of new instantaneous arc models with current-dependent arc voltages, which better represent the arcing phenomenon than the assumed arc voltage associated with previous instantaneous arc models. The arc currents in a typical medium-size building system are determined and harmonic analysis is performed Excerpt: "ARCING FAULTS have been recognized as a potential hazard in low-voltage systems as far
back as the 1920s [1]"
[26] Gammon, T. & Matthews, J., "The historical evolution of arcing-fault models for low-voltage systems", Industrial & Commercial Power Systems Technical Conference, 1999 IEEE.
Aug 1999 Abstract:
An arcing fault is a dangerous form of short-circuit that may have a low current magnitude. In the case of such faults, the magnitude of the current is limited by the resistance of the arc and may also be limited by the impedance of a ground path. This lower level of fault current is often insufficient to immediately trip overcurrent devices, resulting in the escalation of the arcing fault, increased system damage, tremendous release of energy and threat to human life. Despite modern advances in system protection, many people are critically injured or killed each year as a result of such faults. The initial phase of an ongoing arcing-fault research project was to review the pioneering work, dating back to the 1920s. After a comprehensive literature search was completed, today's sophisticated analytical tools are aiding development of a new arc model. An improved arc model will more accurately calculate the arc currents in an actual arcing event. This paper summarizes the physics involved and describes the historical evolution of arc modeling. The condensed review presented in this paper facilitates a better understanding of arcing faults in low-voltage power systems; in addition, it serves as a foundation for current and future research
"Electrical System Inspection Basics," Richard C. Wolcott, ASHI 8th Annual Education Conference, Boston 1985.
"Simplified Electrical Wiring," Sears, Roebuck and Co., 15705 (F5428) Rev. 4-77 1977 [Lots of sketches of older-type service panels.]
"How to plan and install electric wiring for homes, farms, garages, shops," Montgomery Ward Co., 83-850.
"Simplified Electrical Wiring," Sears, Roebuck and Co., 15705 (F5428) Rev. 4-77 1977 [Lots of sketches of older-type service panels.]
"Home Wiring Inspection," Roswell W. Ard, Rodale's New Shelter, July/August, 1985 p. 35-40.
"Evaluating Wiring in Older Minnesota Homes," Agricultural Extension Service, University of Minnesota, St. Paul, Minnesota 55108.
"Electrical Systems," A Training Manual for Home Inspectors, Alfred L. Alk, American Society of Home Inspectors (ASHI), 1987, available from ASHI. [DF NOTE: I do NOT recommend this obsolete publication, though it was cited in the original Journal article as it contains unsafe inaccuracies]
"Basic Housing Inspection," US DHEW, S352.75 U48, p.144, out of print, but is available in most state libraries.
In addition to citations & references found in this article, see the research citations given at the end of the related articles found at our suggested
Carson, Dunlop & Associates Ltd., 120 Carlton Street Suite 407, Toronto ON M5A 4K2. Tel: (416) 964-9415 1-800-268-7070 Email: info@carsondunlop.com. Alan Carson is a past president of ASHI, the American Society of Home Inspectors.
Carson Dunlop Associates provides extensive home inspection education and report writing material. In gratitude we provide links to tsome Carson Dunlop Associates products and services.