Electrical Circuit Breaker Failures & Failure Test Results

Failure Rates of New Off-the-Shelf Circuit Breakers

A 2017 study by Dr. Jess Aronstein found significant no-trip failures among three brands of circuit breakers (UBI, Siemens/Murray)* and essentially no significant failure rates among three other brands of circuit breakers:

Above: test results for common brands of new circuit breakers as of 13 October 2017. [Click to enlarge any image]

Dr. Aronstein, an independent electrical engineer who has performed testing for various government and private agencies notes that the UBI-brand circuit breakers were the worst performing of the group tested.

Aronstein commented (May 2017):

The UBIs are the worst of the lot, and they are the only ones other than FPE that have shown a tendency for the 2-pole breakers to jam.

The surprise was that the Siemens and Murray (identical breakers with different paper labels on them) are not meeting the UL spec.

Next problem is that although many people and organizations have the authority to do something about it, nobody has the responsibility to take any action.

Electrical Wire Failures: Causes vs Time: Bathtub Curve

A 1980 US CPSC study found that aging electrical systems are a factor in the occurrence of electrical fires in homes, an observation confirmed separately by Aronstein in explaining aluminum wiring hazards in what Aronstein calls the "bathtub curve" that maps failure rates over time.

Failures occur early in the wiring system life due to original installation defects and then failures occur again at an increased rate late in the installation's life as the wiring ages and as it has been exposed to the vagaries of use over decades. This bathtub curve of failure rates is illustrated

at ALUMINUM WIRING SAFETY ASSESSMENT.

Older homes often have electrical receptacles and fixtures that are ungrounded, and many local codes do not require that they be rewired so they're grounded. Still, grounding is worth adding to your system because it adds protection against electrical shock.

But Dini points out that "... most of the hazardous conditions found in the 30 houses [studied] could be attributed to a lack of compliance with a specific code requirement". (Dini 2008).

Other Siemens Circuit Breaker Failure Studies or Reports

• Krause, David, Siemens 3VF5111 Circuit Breaker Internal Short Circuit Troubleshooting (IMD Website article) 4 May 2026, Industrial Monitor Direct, Sanford Maine, local off line backup copy saved as Siemens-3VF-Breaker-Failure-IMD.pdf
  Excerpt:
  Five units of the Siemens 3VF5111-6EL71-0AS1 circuit breakers (315A, 400V) have failed with apparent internal short circuits. The breakers are integrated into motor starters. Initial investigation suggests the failures are not caused by external components such as cables, contactors, or motors—indicating a potential manufacturing defect or application mismatch.
  
  Root Cause Analysis:
  The most critical factor in premature circuit breaker failure is inadequate fault current rating. Circuit breakers must be selected based on the available short-circuit current at their installation point, not merely the full-load current.
  
  - About the author: David Krause, Industrial Controls Specialist – Siemens Platforms Industrial controls specialist focused on Siemens SIMATIC S7 platform, from the S7-300/400 series through the latest S7-1200/1500 controllers. Expert in TIA Portal configuration and WinCC SCADA integration.
• MURRAY SIEMENS Recall (at InspectApedia)
• Quad Plus, Detecting and Repairing a Failing Circuit Breaker Safely [Web Article] Quad Plus, Tel: (844) 515-4201 (Quad Plus is a global industrial engineering services company. )
  Excerpt
  

  The main problems for the industrial circuit breaker testing team included:

  • Insulated case circuit breakers with faulty trip units that would not open during an actual fault.
  • Breakers with mechanical damage from rough handling or age
  • Breakers in need of lubrication were no longer operating as expected.
  • The low-voltage distribution breakers spanned a number of makes and models, such as Siemens WL, GE AKRU, ABB SACE, and ITE K-Line.
  
  
• US CPSC, Siemens recalls 2.2 million circuit breakers [CPSC Web Article, breaker recall] (2010)
  Excerpt: Siemens has recalled 2.2 million circuit breakers, load centers, and meter combos after an installer reported a spring clip that broke during installation creating a fire hazard, the Consumer Product Safety Commission announced today.
  
  While no incidents have been reported, the CPSC warns that the broken spring clips can lead to a loss of force to maintain a proper electrical connection in the panel board. This can, in turn, lead to excessive temperature, arcing or thermal damage at the connection point, and damage to the panel board's electrical insulation posing the threat of fire, property damage or personal injury.
  
  The recall involves Siemens and Murray 15 through 50 AMP single and double pole circuit breakers, load centers (circuit breakers that come with an electrical panel), and meter combos (contain a load center and a meter socket).
  
  "Siemens" or "Murray," date codes 0610 or 0710 and the catalog number are printed on a label on the side of the circuit breakers. Date codes between June 2010 through August 2010 are stamped on the inside of the metal box of the load centers and meter combos. The catalog number for the load centers and meter combos is printed on a label inside the metal box door and on the packaging. (Check the recall notice for date codes and catalog numbers.)
• US CPSC, Siemens Announces Free I-T-E Circuit Breaker Box Inspection Program [CPSC Web article describes a product recall] (1988)
  Excerpt:
  Some of the circuit-breaker boxes were manufactured using components of an incorrect material, which could cause overheating and malfunction.
• Siemens AFCI Nuisance Tripping Class Action Lawsuit - cited, with links, discussed in NUISANCE TRIPPING of AFCIs
• Siemens, 3VA molded case circuit breaker – condition monitoring [PDF] (2020) (At Siemens Website) Siemens AG, Smart Infrastructure, Electrical Products, Siemensstrasse 10 93055 Regensburg, Germany, local backup saved as Siemens-3VA-CB-Monitoring.pdf
• Mike Holt's Forum, Circuit Breaker teardown and defective Siemens latching mechanism (Web Article) (2019) reports on a Siemens circuit breaker "latching anomaly". - local backup copy saved as Circuit Breaker teardown and defective Siemens latching mechanism _ Mike Holt's Forum.pdf

Failure Rates of Used Circuit Breakers

[Click to enlarge any image]

Source of the table above: personal email, Dr. Jess Aronstein to Daniel Friedman, 2017/05/11 & 2017/10/19.

Above, circuit breaker failure test results for these circuit breaker brands (left to right): Bryant/Westinghouse, Square-D, Bulldog (Pushmatic), GE, ITE, Zinsco, FPE (Stab-Lok), UBI (replacement breakers for several panels), Murray, Crouse Hinds.

This failure data test report is as of 29 September 2017 and includes tests performed by David W. Carrier and Jess Aronstein between 2013 and 2017.

At MOLDED CASE CIRCUIT BREAKERS - SOME HOLES IN THE ELECTRICAL SAFETY NET [PDF] you will find the latest research by these authors in an IEEE paper to be published in 2018.

Notes on Aronstein's chart indicate:

1. Data points on this chart are 1-pole breakers and worst case poles of 2-pole breakers.

2. These used [circuit] breakers are field samples that were removed from buildings during upgrades or renovations.

3. FPE [circuit breaker failure test result] data is representative of 3000 breakers that have been tested.

Contribute UBI (Connecticut Electric) and Zinsco Brand Circuit Breakers for Independent Testing

Dr. Aronstein would like to obtain and test UBI (Connecticut Electric) Zinsco type replacement breakers that might be in your electrical panel. They are usually grey in color, and might have been installed as replacements or when new circuits were added.

To date I have tested only four of the UBI-Z types, and all four failed to perform properly. If you have any of the UBI-Z breakers, please send them to:

Jesse Aronstein, Ph.D., P.E.
909 Londonderry Ct.
Schenectady, NY 12309

Noting that you found this request at this InspectApedia.com web page: https://inspectapedia.com/electric/Circuit_Breaker_Failures.php

Articles describing other in-service or "used" circuit breaker brands are included in this article below

at CIRCUIT BREAKER FAILURE RESEARCH.

The circuit breaker test standard, UL-489, is described and cited

at UBI FPE CIRCUIT BREAKER TEST RESULTS where you will also find additional test results that included both new and used UBI circuit breakers.

Reader Question:where to find performance data on various circuit breakers

(Nov 20, 2014) Steve L

I'm looking to replace an old panel for a variety of reasons. I'm wondering where I can find recent performance/fire/etc data on various brands of circuit breakers so I can form an idea of which brands to favor or avoid in selecting a new panel.

I'm also curious about which brands have the best performing (C)AFCI and GFCI breakers since most searches are flooded with the problems that all brands had in the early days of AFCI. Is there are good source for this information? Many thanks!

This question was originally posted

at ELECTRICAL INSPECTION, DIAGNOSIS, REPAIR

Reply:

Steve you ask a fair question.

From speaking with industry experts over several decades it's apparent that most of the circuit breakers and panels by major equipment manufacturers perform very well, with failure-rates (as in fail-to-trip in response to an overcurrent) are at a very small fraction - well under 1 per-cent.

The highest "generic" opinion about circuit breaker failure to trip rates that I have found was reported at 4% as anecdotal evidence by Koty (undated, retrieved 2015, cited below).

Our OPINION is that in most installations conventional residential circuit breakers from most manufacturers almost never fail to trip when they should - certainly that is the expectation of consumers.

Illustrated above, a Classified circuit breaker (burned, damaged) discussed

at Classified CIRCUIT BREAKER WARNING.

A few brands of older equipment described in articles at InspectApedia such as Challenger, FPE-Stab-Lok, Zinsco have notably higher problem and failure rates, in some cases as high as 60% no-trip rates. That's a failure rate around 600 times worse than what we expect in the industry.

We are now in the 4th generation of AFCI devices - so I would not tar current brands with more historical issues, but I agree that nuisance tripping, particularly on AFCI's has been a reported problem yet to be fully addressed.

See AFCIs ARC FAULT CIRCUIT INTERRUPTERS for examples. That article includes a link to an IEEE article on what we can and cannot expect from AFCIs and how they perform.

David Carrie, a New York electrical engineer briefly continued Jess Aronstein's work on testing circuit breaker performance independently of work supported by manufacturers but regrettably, although he reported (to me privately) that some current circuit breaker brands seemed to have higher no-trip rates than the industry average, he did not complete nor report that research publicly.

By 2014 it appeared that David had moved on to other projects. Dr. Aronstein took up that task once again and in 2017 we include some of his recent test results here.

See UBI FPE CIRCUIT BREAKER TEST RESULTS.

Warning about Do-It-Yourself Circuit Breaker Testing

Watch out: circuit breaker trip testing such as described both by Koty (op.cit). and by vendors of clamp-on ammeters is a dangerous proposal, especially if the breakers and equipment are installed in the building they are intended to serve. For example testing a circuit breaker in-situ in a home by putting a deliberate overload on the circuit risks setting the building on fire.

Other do it yourself or homeowner circuit breaker testing risks include inaccurate test results, conducting an improper test that does not properly assure that the circuit breaker will perform correctly under varying conditions of load, time, and environments, reporting as "safe" a breaker that is in fact not compliant with ANSI C37 nor UL standards such as UL 489 or other pertinent circuit breaker testing standards, and worst: some problem brands such as FPE experience an increased fail-to-trip rate (fail to open in response to an over current) after the breaker has been "exercised" either by switching it on and off or by exposing it to an overcurrent.

We do not recommend circuit-breaker testing by homeowners, electricians, nor in-situ testing of circuit breakers unless conducted by an expert.

Full View of Electrical Panel with a Burned Circuit Breaker

You don't need a VOM or digital volt meter to see bad burn ups like the circuit breaker failures shown in this article 

but this failure is a strong recommendation for use of digital multimeters or simple neon testers to confirm that circuit breakers really do turn off the power.

On opening the panel, arcing and burn marks were obvious. Note the black stains along the left side of the right-hand bus bar above the highest breaker in the panel.

Note also the corrosion present at the neutral bus and bus bar connector at the panel bottom right corner. This panel was in a wet utility basement of an old house in New York state.

However it did not appear that moisture in the panel from basement conditions was the root cause of overheating and damage. There was not general corrosion throughout the panel.

The panel itself was relatively new, less than ten years old.

A Closer Look at the Electrical Panel Center

A look at the center of the panel shows pieces of circuit breaker plastic and other debris that was obviously a product of arcing and burning at one of the circuit breakers.

Close up View of the Electrical Panel Center

A closer look at the same area shows a piece of one of the right-hand breakers sitting atop the lower breaker on the left. Notice the red and white corroded material at the lower right corner of the top breaker.

J. Aronstein suggests that overheating in the breaker burned off zinc or other anti-corrosive plating leading to bleed-out of rust particles.

Other breakers in the panel, presumably of the same age, did not show these visual indications of damage.

Burned, arced breaker still in place, still "live"

Finally, shifting the angle and getting some better light on the subject one could see that the lower of the uppermost two breakers in the panel right side had burned badly where it was connected to the aluminum bus of the panel.

It was remarkable that despite severe damage to the breaker and panel bus, the breaker was still conducting current to the circuit connected to it.

During a home inspection inspectors should not touch equipment like this. Using a TIF Instruments Tic Tracer it was possible to confirm live electrical power at various points. Of course, what's called-for is an immediate repair which most likely requires replacement of the bus assembly and breakers if not the whole panel.

Home inspectors are not forensic engineers, but it appears obvious to anyone looking at this equipment in-situ that overheating at the connection of the breaker to the panel bus must have led to arcing, breaker damage, and thus creation of an unsafe condition in which there is very likely no overcurrent protection being provided by this equipment.

You don't need a VOM or digital volt meter to see bad burn ups like this but this failure is a strong recommendation for use of digital multimeters or simple neon testers to confirm that circuit breakers really do turn off the power.

Research on Electrical Circuit Breaker Performance & Failure Rates

Recent research citations on circuit breaker performance and breaker failure rates such as no-trip or failure to trip in response to an over-current.

Watch out: recent research (Aronstein 2026) confirms and underscores prior work indicating that some residential circuit breakers are unsafe.

• ALUMINUM WIRING HAZARDS & REPAIRS [Web article] aluminum electrical wiring can cause fires without tripping a circuit breaker
• AFCIs ARC FAULT CIRCUIT INTERRUPTERS [Web article] nuisance tripping
• Aronstein, Jesse, (Life Senior Member, IEEE), INEFFECTIVE CALIBRATION TESTING OF RESIDENTIAL BRANCH CIRCUIT BREAKERS [PDF], Copy courtesy of Dr. Aronstein, thie article was published in IEEE Open Journal of Industry Applications, 13 March 2026.
  
  ABSTRACT
  
  Previous test results demonstrated that some presently-marketed residential branch-circuit breaker brands have a double-digit defect rate.
  
  The defective breakers do not trip as required at 135% of rated current.
  
  The unique test results reported in this article clearly show that these calibration defects cannot be reliably detected by testing at 200% or 300% of rated current.
  
  One hundred defective breakers of three brands from the previous tests are retested. They all fail to trip at 135% of rated current, confirming that they are defective.
  
  The defective breakers then all pass the UL489 calibration test at 200% of rated current (must trip within 120 s), and they all also pass the NEMA AB4 calibration test at 300% of rated current (must trip within 50 s).
  
  These higher-current tests have a 100% error rate for detection of these improperly calibrated breakers.
  
  This explains how defective breakers come to be shipped from some factories. For some residential branch circuit breaker brands, ineffective testing - relying only on high-current calibration testing - has allowed defective breakers into the supply chain for many decades, increasing the risk of fire and injury for occupants of the buildings in which they are installed.
  
  Editor's note: In Aonsteing's article above, Ref [17] the second author's name should be McCoskrie (with a "k"), and there is an error in the link. the correct link is given here: RESIDENTIAL ELECTRICAL DISTRIBUTION SYSTEM FIRES [PDF ] (1987)
  
• Aronstein, Jesse. "Temperature Sensitivity of Residential Molded Case Circuit Breakers." IEEE Access 7 (2019): 38714-38720.
  
  This report can can be download as a PDF from IEEE at no cost at the following
  
  URL: https://ieeexplore.ieee.org/document/8669748 but may not be reproduced without IEEE permission - Ed.
  
  ABSTRACT
  
  The experimental results are presented for minimum trip current as a function of temperature for residential circuit breakers. These are often installed in enclosures that are exposed to seasonal temperature extremes.
  
  The trip current of these thermally actuated breakers is inversely related to temperature. The relationship is shown to be linear and it varies as much as 2:1 between brands.
  
  The trip current at extremely high and low temperatures can be estimated. At low outside ambient temperature the worst case 15A breakers will not trip at 25 A, which would be the current load of two 1500W portable heaters plugged into the same 15 A circuit.
  
  The diminished overcurrent protection at low temperature may be a factor that contributes to the elevated incidence of residential electrical fires during winter months.
• Aronstein, Jess ¹, (Life Senior Member, IEEE), & David W. Carrier ² MOLDED CASE CIRCUIT BREAKERS - SOME HOLES IN THE ELECTRICAL SAFETY NET [PDF]
  
  Received December 4, 2017, accepted January 24, 2018, date of publication February 7, 2018, date of current version March 15, 2018. Digital Object Identifier 10.1109/ACCESS.2018.2803298
  1 Consulting Engineer, Schenectady, NY 12309, USA, 2 SUNY Dutchess Community College, Poughkeepsie, NY 12601, USA, Corresponding author: Jesse Aronstein (AronsteinJ@verizon.net)
  
  This paper is also available at no charge at the IEEE Explore website. It can be accessed for online reading at: http://ieeexplore.ieee.org/document/8283732/

and can be downloaded directly from IEEE at http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=8283732

Abstract:
Test results presented in this paper demonstrate that some brands of residential molded case circuit breakers do not operate properly within the limits specifieded by the applicable standard. The samples tested are both used, from homes, and new, purchased at retail sources. The minimum trip current is determined for each breaker.

The test procedure encompasses the basic overload trip requirements of the applicable standard. Breakers that do not open the circuit at or below 135% of rated current fail to meet the requirements of the standard. Test results vary substantially from brand to brand.

The best brands are essentially failure free.

The failure rate of the worst-case brands is in the order of 50% for both used breakers from homes and new breakers recently purchased. Some samples, primarily multi-pole breakers, do not open the circuit at any level of applied current.

Failure of a circuit breaker in a home to operate properly when required poses an increased risk of fire and injury.
• Aronstein, Jesse, and Richard Lowry. ESTIMATING FIRE LOSSES ASSOCIATED WITH FPE STAB-LOK® CIRCUIT BREAKER MALFUNCTION [PDF] In Electrical Safety Workshop (ESW), 2011 IEEE IAS, pp. 1-7. IEEE, 2011. - retrieved 2021/06/25 original source: http://www.fpe-info.org/estimating_fire_losses_due_to_fpe_malfinction.pdf
  Abstract:
  
  A method is presented for connecting small branch circuit breaker functional test data to statistical fire loss data.
  
  Test results are presented for field samples of a particular line of circuit breakers that have an abnormally high defect level.
  
  The test results are then utilized in combination with available electrical fire statistics to estimate the annual number of fires and consequent injuries, deaths, and monetary loss associated with the defective breakers.
  
  An estimate is then made of the reduction of injury and loss that can be achieved by encouraging replacement of the defective breakers. The role of the electrical safety community in promoting replacement of the defective breakers is discussed.
• "Failure Analysis of Residential Circuit Breaker Panel", Wright-Malta Corp., (by J. Aronstein, for U.S. Consumer product Safety Commission, Project #CPSC-C-81-1455), May 20, 1982 (Contains failure analysis of FPE Stab-Lok® panel that ignited, due to failure of buss-bar interconnections in the backside of
  the panel.)
• "Final Report: Calibration and Condition Tests of Molded Case Circuit Breakers", Wright-Malta Corp., (by J. Aronstein, for U.S. Consumer product Safety Commission, Project #CPSC-C-81-1429), December 30, 1982 (Extensive calibration and functional testing of FPE breakers. Substantial percent failures
  to trip on overload.).
• "Status Report - Evaluation of Residential Molded Case Circuit Breakers", Wright-Malta Corp., (by J. Aronstein, for U.S. Consumer product Safety Commission, Project #CPSC-C-81-1455), August 10, 1982 (Contains analysis of mechanism of failure of FPE two-pole Stab-Lok® breakers.)
• "Phase II Report, Evaluation of Residential Molded Case Circuit Breakers", Wright-Malta Corp., (by J. Aronstein, for U.S. Consumer product Safety Commission, Project #CPSC-C-81-1455), March 10, 1984 (Contains experimental analysis of materials, construction, and performance of molded case circuit breakers, including FPE.)
  
  and citing: Partial Summary Judgment decision dated 8/15/02 by Judge Bryan D. Garruto, J.S.C., Superior Court of New Jersey, Law Division: Middlesex County, Docket No. L-2904-97
• Anderson, J. G. P., N. S. Ellis, F. Mason, R. G. Noble, L. H. Orton, M. P. Reece, and J. G. Steel. "Synthetic testing of ac circuit breakers. Part 1: Methods of testing and relative severity." In Proceedings of the Institution of Electrical Engineers, vol. 113, no. 4, pp. 611-621. IET Digital Library, 1966.
• ANSI C37, 50-2012, Low-Voltage AC Power Circuit Breakers Used in Enclosures ù Test Procedures, ANSI Attn: Customer Service Department 25 W 43rd Street, 4th Floor New York, NY, 10036, USA, E-mail: info@ansi.org Phone: 212.642.4980, Website: http://webstore.ansi.org/
  Abstract:
  
  Covers the test procedures for enclosed low-voltage ac power circuit breakers as follows:
  
  a) Stationary or drawout circuit breakers of two-, three-, or four-pole construction, with one or more rated maximum voltages of 635 V (600 for units incorporating fuses), 508 V, and 254 V for application on systems having nominal voltages of 600, 480, and 240 V;
  
  b) Unfused or fused type circuit breakers;
  
  c) Manually operated or power operated circuit breakers with or without electromechanical or solid-state trip devices;
  
  d) Fused drawouts consisting of current-limiting fuses in a drawout assembly intended to be connected in series with a low-voltage ac power circuit breaker to form a non-integrally fused circuit breaker. This document applies to both integrally and non-integrally fused circuit breakers.
• Babrauskas, Vytenis, HOW DO ELECTRICAL WIRING FAULTS LEAD to STRUCTURE IGNITIONS [PDF file downloaded 2017/03/15] (At InspectApedia) In Proc. Fire and Materials 2001 Conf, pp. 39-51. 2001.
  Abstract:
  
  A sizable fraction of ignitions of structures are due to electrical faults associated with wiring or with wiring devices.
  
  Surprisingly, the modes in which electrical faults progress to ignitions of structure have not been extensively studied. This paper reviews the known, published information on this topic and then to point out areas where further research is needed.
  
  The focus is solely on single-phase, 120/240 V distribution systems. It is concluded that systematic research has been inordinately scarce on this topic, and that much of the research that does exists is only available in Japanese.
• Billinton, Roy, Ronald Norman Allan, and Ronald N. Allan. Reliability evaluation of power systems. Vol. 2. New York: Plenum press, 1984.
• Braun, A. "Validity of Unit Testing on Circuit-Breakers Exhibiting Statistically Varying Breaking Capacity." Power Apparatus and Systems, IEEE Transactions on 3 (1972): 791-797.
• BRYANT ELECTRICAL PANEL AGE & PROPERTIES
• CHALLENGER ELECTRIC PANELS [Web article] Challenger Electric panel history, field reports of overheating bus bars & circuit breakers, history, relationship to FPE Stab-Lok equipment
• Classified CIRCUIT BREAKER WARNING [Web article] from Square-D who explains the company's opposition to use of interchangeable or substitute circuit breakers
• COUNTERFEIT SQUARE-D CIRCUIT BREAKER RECALL [Web article] CPSC Notices Regarding two circuit breaker products: Recalled Square-D Circuit GFCI Breakers and Counterfeit Square-D Breakers.
• CPSC, TECHNOLOGY FOR DETECTING AND MONITORING CONDITIONS THAT COULD CAUSE ELECTRICAL WIRING SYSTEM FIRES [PDF] (1995) (CPSC Website) UL, Underwriters Laboratories, 333 Pfingsten Road Northbrook, IL 60062 and 1285 Walt Whitman Road Melville, NY 11747, USA, Contract Number CPSC-C-94-1112 - local backup copy saved as Technology-for-Reducing-Resid-Elec-Fires-CPSC-UO.pdf
  
  The UL project investigators were Messrs. Peter Boden, Robert Davidson, Walter Skuggevig, and Richard Wagner. Mr. John Stevenson (retired from UL) was a consultant providing technical advice and reviewing services. Mr. David Dini was the project manager.
  
  The CPSC estimates that there were approximately 41,000 fires involving home electrical wiring systems in 1992. These fires resulted in 320 deaths, 1,600 injuries, and $511 million in property losses. CPSC studies have also shown that the frequency of wiring system fires is disproportionately high in homes more than 40 years old.
  
  Identifying Technology-for Reducing Residential Electrical Fires The purpose of the project reported here was to conduct an in-depth study of technologies to detect and monitor precursory conditions that could lead to or directly cause fires in residential wiring systems in general, and how these technologies could be applied to older residential wiring systems in particular.
  
  The project included
  
  1) conducting a comprehensive review of published and unpublished literature on devices and systems that could decrease the likelihood of residential fires,
  
  2) a survey of industry organizations and manufacturers for new products and systems that could decrease the likelihood of residential fires, and 3) the acquisition and analysis of promising devices and systems for ease of installation, reliability, cost and effectiveness in decreasing the likelihood of fires in residential wiring systems, particularly older residential wiring systems.
  
  ...
  
  "The Fire Investigation Handbook", ibid footnote 2, refers to "Arc Faults" as those which are "caused by high-voltage breakdown of the air gap between a conductor and ground or between two electrical phases of a three-phase distribution system."
  
  
  The "Carbonized Path Arc Fault" and "Partial Carbonized Path Arc Fault" tests conducted under this project are intended to represent the end state, or near end state, of the formation of a carbonized path. Although the technique used to create the carbonized path was to use high voltages, the end result may be considered representative of any of the mechanisms described above.
  
  Decomposed insulation between opposite polarity conductors or between a line voltage conductor and ground can lead to an across-the-line arcing fault or a line-to-ground arcing fault.
  
  The fault current will depend upon the total impedance in the circuit containing the fault. If the decomposed insulation is in series with the load, as in the case of tracking across insulation between terminals of a single pole switch while the contacts are in the open position or in the case of carbonization of insulation at a broken conductor (see closing/parting conductors, below), then the arcing fault condition is referred to as a series arcing fault. In this case, the fault current generally limited by the load (unless the series fault is combined with an overload, short circuit or ground fault downstream).
  
  Finally, since decomposed (i.e., carbonized) insulation is involved in each of these arcing fault conditions, arcing fault conditions are referred to as carbonized path arcing faults. The "Carbonized Path Arc Fault" and "Partial Carbonized Path Arc Fault" tests conducted under this project are intended to represent the end state, or near end state, of the formation of a carbonized path.
  
  Although the technique used to create the carbonized path was to use high voltages, the end result may be considered representative of any of the mechanisms described above. - p24
• CPSC, 1999 Revised - 2002 Residential Fire Loss Estimates∗ U.S. National Estimates of Fires, Deaths, Injuries, and Property Losses from Unintentional Fires [PDF] (2005) (US CPSC Website) Authors: Risana Chowdhury Michael Greene David Miller Linda Smith Division of Hazard Analysis Directorate for Epidemiology U.S. Consumer Product Safety Commission Washington, DC 20207 November 2005 - local backup coy saved as Fire-Loss-Estimates-CPSC-2002.pdf
  
  Excerpts:
  The fire and fire loss estimates presented in this report pertain to residential structure fires, resulting in civilian deaths and injuries. These estimates show that there were:
  • 338,100 fires, 2,400 deaths, 14,590 injuries, and $4.24 billion in property loss in 1999,
  • 337,600 fires, 2,720 deaths, 15,740 injuries, and $4.78 billion in property loss in 2000,
  • 361,200 fires, 2,570 deaths, 14,040 injuries, and $4.39 billion in property loss in 2001, and
  • 369,000 fires, 2,270 deaths, 12,870 injuries, and $5.32 billion in property loss in 2002.
  
  Cooking equipment (Table 1) accounted for the largest percentage of fires, averaging about 29.5% of total fires.
  
  Heating and cooling equipment fires accounted for an average of 14.4% of the total fires.
  
  For 1999 and 2000, an average of 10.8% of total fires was attributable to electrical distribution system components (e.g., wiring, lighting, etc.). For 2001 and 2002, these components accounted for about 7.0% of the total fires. The corresponding death estimates varied between a high of 11.4% of total deaths in 2000 and a low
  
  By item first ignited (Table 2), upholstered furniture ignition was involved in the greatest number of deaths, accounting for an average of 20.9% of the total deaths associated w
  
  By heat source, smoking materials were the largest contributor to deaths, accounting for an average of 28.5% of fire deaths. Death estimates from lighter fires varied between 1.6% (in 2001) and 4.0% (in 2002) of total deaths. Candles were responsible for 3.3% of total deaths in 1999; that proportion went up to 7.8% in 2001, dropping back slightly to 5.7% in 2002. Matches were responsible for an average of 1.5% of total deaths over the four years
  
  
• CPSC FPE FAILURE DATA 1982 [Web article] FPE Stab-Lok circuit breaker failure rate data: This article presents research data demonstrating the failure rates of Federal Pacific Electric Stab-Lok® circuit breakers. web article at InspectApedia.com
• CUTLER HAMMER ELECTRICAL PANELS [Web article] photographs of older Cutler Hammer electrical panel using a copper bus & comments on its condition. Separate field report of a Cutler Hammer Electrical Panel Fire, Photos, with speculation about possible causes.
• Dakin, T. W. ELECTRICAL INSULATION DETERIORATION TREATED AS A CHEMICAL RATE PHENOMENON (Copy available through IEEE) Trans. Amer. Inst. Elect. Eng., vol. 67, no. 1, pp. 113–122, Jan. 1948. - DOI:10.1109/T-AIEE.1948.5059649Corpus ID: 51671845 - Local backup copy saved as Electrical-Insulation-Deterioration-Dakin-1948.pdf
  
  Abstract:
  
  The basis is presented for a more accurate interpretation of the results of physical type tests to measure the thermal aging of insulation together with a more accurate method of applying the results of such tests to predicting insulation deterioration in practice. Since the observed physical changes during thermal aging are the result of internal chemical changes in organic material, it is shown that the theory of chemical reaction rates can be applied to analyze experimental data on aging.
  
  The approximate 7 to 10 rule for the temperature coefficient of deterioration rate is replaced by a more accurate theoretical expression. Various examples of insulation life tests are analyzed using the graphical methods outlined in the paper. The chemical rate theory interpretation of thermal aging offers a more satisfactory method for extrapolating the results of limited aging tests of insulating materials so they can be applied to predicting amounts of thermal aging in high temperature cycles.
• Dehghanian, Payman, and Mladen Kezunovic. "Cost/benefit analysis for circuit breaker maintenance planning and scheduling." In North American Power Symposium (NAPS), 2013, pp. 1-6. IEEE, 2013.
  Abstract:
  
  Maintenance planning and scheduling of circuit breakers (CBs) always involves the cost and benefit analysis. This paper introduces a new framework for cost/benefit assessments using condition-based monitoring data. The signals monitored at the CB control circuit are first utilized to determine the CB deterioration status.
  
  This information is used to decide which type of maintenance, e.g., minor, major, or replacement, needs to be practiced for different CBs. System wide analysis is then performed to assess the cost benefits of the maintenance by calculating the costs imposed to the system in the case of CB mal-operation.
  
  A new benefit to cost ratio (BCR) index is introduced to deal with the CB maintenance prioritization process.
  
  The proposed approach is implemented on a breaker-and-a-half substation configuration and the results demonstrate the applicability of the presented framework in real world scenarios.
• Dini, David A RESIDENTIAL ELECTRICAL SYSTEM AGING RESEARCH PROJECT [PDF] Fire Protection Research Foundation, Quincy, MA (2008). Retrieved 6/6/2010, original source: http://ul.com/global/documents/corporate/aboutul/publications/newsletters/thecodeauthority/tca_issue_2_2008.pdf
  and
  The Residential Electrical System Aging Research Project done for NFPA/FPRF is available in its entirety at this site, http://ewh.ieee.org/cmte/pses/ffat/support/RESAReport.pdf
• Emanuel, A. E., and John W. Dougherty. "Sensitive ground fault interrupter performance in the presence of direct current." Power Delivery, IEEE Transactions on 1, no. 1 (1986): 111-117.
• FEDERAL NOARK PANEL FAQs [Web article]
• FEDERAL PACIFIC FPE HAZARDS [Web article] fire and shock hazards associated with Federal Pacific Electric Stab-Lok® circuit breakers and service panels
• FPE Stab-Lok® : FIRES WAITING TO HAPPEN [Web article] description of the Latent Fire, Shock Hazards of FPE Stab-Lok® Equipment also may show up in CHALLENGER ELECTRIC PANELS brand electrical panels.
• FEDERAL PIONEER CIRCUIT BREAKER RECALL [Web article] Recall of Federal Pioneer NC015 and NC015CP Circuit Breakers in Canada
• FEDERAL PIONEER PANEL SAFETY - 2023 update & prior research on on Canadian FP breaker and panel failures confirms a similar failure rate as U.S.
• Fu, Xing, Xiaorui Wang, and Charles Lefurgy. "How much power oversubscription is safe and allowed in data centers." In Proceedings of the 8th ACM international conference on Autonomic computing, pp. 21-30. ACM, 2011.
  Abstract:
  
  Data centers attempt to maximize return on investment by achieving high levels of utilization. This means deploying the maximum number of servers possible within existing power supply capabilities. Therefore, a key problem is determining how many servers can be safely accommodated.
  
  Recently, a variety of power capping solutions have been proposed to safely allow oversubscription of available power, but they conservatively assume that peak power should never exceed the rated power distribution equipment capacity. Hence, the open question is: how much power oversubscription is indeed safe? In this paper, we focus on data center branch circuits and systematically study the tripping characteristics of their circuit breakers (CBs).
  
  Our results on a physical testbed show that instantaneous violations of the rated CB power limit are not necessarily fatal because CBs are designed to sustain a certain amount of power overload.
  
  Whether a CB trips or not depends primarily on the transient behaviors of a power overload, such as the magnitude and duration time, as well as ambient temperature. We propose two adaptive power control strategies that utilize the CB tripping characteristics to aggressively optimize the system performance without causing the CB to trip.
  
  Our extensive hardware results with SPEC CPU2006, SPECJBB, and LINPACK benchmarks show that the proposed CB-aware power control solutions achieve 38%, 75%, and 68% better average performance, respectively, than a state-of-the-art baseline.
  
  A key contribution of our work is to provide a practical upper bound of the server power oversubscription allowed on branch circuits. As a result, our solutions allow a data center to host three times more servers than traditional static power provisioning schemes and 54% more servers than the current power capping practice.
• Gregory, George D., and Gary W. Scott. "The arc-fault circuit interrupter, an emerging product." In Industrial and Commercial Power Systems Technical Conference, 1998 IEEE, pp. 48-55. IEEE, 1998.
• Hall, William M., Gary Donner, Banafsheh Kalhori, George D. Gregory, John Gardner, and Matt Samojeden. "A user guide to the selection, application, testing and life expectancy of molded case circuit breakers." In Petroleum and Chemical Industry Conference, 1995. Record of Conference Papers., Industry Applications Society 42nd Annual, pp. 65-75. IEEE, 1995.
  Abstract:
  
  A working group representing the PCIC and I&CPS and manufacturers are preparing a guide to give users information for the correct selection, application, testing, and life expectancy of molded case circuit breakers. This paper is intended to be a tutorial type presentation.
  
  This is the first phase of the solution to understanding the present method of rating molded case circuit breakers.
• Heunis, Schalk W., and Ron Herman. "A probabilistic model for residential consumer loads." Power Systems, IEEE Transactions on 17, no. 3 (2002): 621-625.
• IEEE Standards Collection, C37 -- Circuit Breakers, Switchgear, Substations, and Fuses, 1995 Edition, The Institute for Electrical and Electronics Engineers, Inc. New York, NY: IEEE
• Kimball, Jonathan, and Jordan Henry. "Compatibility between GFCI breakers and household adjustable speed drives." In Energy Conversion Congress and Exposition, 2009. ECCE 2009. IEEE, pp. 517-520. IEEE, 2009.
• Koty, Ken, "Testing and Exercising Branch Circuit Breakers", web page article, Website: http://www.pducables.com/ Email: kkoty@pducables.com, retrieved 3 April 2015, original source http://www.pducables.com/TestingandExercisingBranchCircuitBreakers.htm
  Excerpt:
  
  I found from my years of experience of testing branch circuit breakers installed in our data centers, between overloaded branch circuits and direct shorts, about a 4% failure rate.
  
  Even though 4% may not seem like a large percentage, in most data centers, 4% of the thousands of circuit breakers used can still place a significant number of servers at risk.
• Lee, Jaebok, Sughun Chang, Sungho Myung, and Yuengue Cho. "Transient false tripping characteristic analysis of ground fault circuit interrupter." In Power System Technology, 2004. PowerCon 2004. 2004 International Conference on, vol. 1, pp. 522-526. IEEE, 2004.
• Lindquist, T. M., Lina Bertling, and Roland Eriksson. "Circuit breaker failure data and reliability modelling." IET generation, transmission & distribution 2, no. 6 (2008): 813-820.
  Abstract:
  
  The results from an extensive study of SF6 and minimum-oil circuit breaker failures in the Swedish and Finnish transmission systems are presented.
  
  The study includes 1546 breakers with a total operating history of 16 384 years. In the study, a detailed analysis of a specific SF6 type of breaker revealed which parts caused the failures and an estimation of their hazard rates was made.
  
  A model of complete reliability for this type of breaker is presented, illustrated by presenting the operating and maintenance history of a shunt reactor breaker in the Swedish transmission system.
• Lippert, Kevin J., and T. Domitrovich. "AFCIs-From a standards perspective." In Electrical Safety Workshop (ESW), 2013 IEEE IAS, pp. 57-61. IEEE, 2013
• MURRAY CIRCUIT BREAKER HAZARDS [ Web article ]
• MURRAY SIEMENS Recall [PDF]
• Mili, Lamine, Q. Qiu, and Arun G. Phadke. "Risk assessment of catastrophic failures in electric power systems." International Journal of Critical Infrastructures 1, no. 1 (2004): 38-63.
  Abstract:
  
  The declining reliability of the US electric power system is raising major concerns among both politicians and power engineers in the USA.
  
  One of the reasons put forward by the North Electric Reliability Council (NERC) is the detrimental role played by the protection systems during large disturbances, which tend to help the perturbations to propagate through over-tripping of fault free system components due to hidden failures.
  
  It turns out that the present practice in power transmission planning and online security analysis is to neglect the impact of the protection systems. In addition, the aim is to mitigate the vulnerability of the system to the loss of a single piece of equipment only by carrying out an N-1 security analysis.
  
  Consequently, the risk of cascading failures leading to blackouts and brownouts is neither assessed nor managed.
  
  This paper describes methodologies together with algorithms that assess the conditional risk of catastrophic failures in electric power networks due to hidden failures in protection systems.
  
  A catastrophic failure, defined as one that results in the outage of a sizable amount of load, may be caused by dynamic instabilities in the system or exhaustion of the reserves in transmission due to a sequence of line tripping leading to voltage collapse.
  
  Only the latter case is being considered. The aim of these algorithms is to identify the weak links in the systems, which are defined as those branches of the network whose tripping due to a fault lead to the highest probabilities of a catastrophic failure.
  
  The proposed methods are demonstrated on a 7-bus and a 61-bus system.
• Natti, Satish, Panida Jirutitijaroen, Mladen Kezunovic, and Chanan Singh. "Circuit breaker and transformer inspection and maintenance: probabilistic models." In Probabilistic Methods Applied to Power Systems, 2004 International Conference on, pp. 1003-1008. IEEE, 2004.
• NEMA Standards Publication AB 4, National Electrical Manufacturers Association, Washington DC 20037: NEMA
• Pahl, Birger, Thomas J. Schöpf, Xin Zhou, and Engelbert Hetzmannseder. "Arc faults in residential electrical systems." VDE-Fachbericht-Kontaktverhalten und Schalten (2009).
• PRIVATE BRAND/ EMI FPE PANELS [Web article]
• PUSHMATIC - BULLDOG PANELS [Web article] Pushmatic Bulldog Circuit Breaker & Electrical Panel Possible Safety & Operating Concerns
• Rusek, Bartosz, Gerd Balzer, Martin Holstein, and Max-Steffen Claessens. "Timings of high voltage circuit-breaker." Electric Power Systems Research 78, no. 12 (2008): 2011-2016.
• SQUARE-D COUNTERFEIT BREAKER RECALL [Web article]
• Schlabbach, Jiirgen, and T. Berka. "Reliability-centred maintenance of MV circuit-breakers." In Power Tech Proceedings, 2001 IEEE Porto, vol. 4, pp. 5-pp. IEEE, 2001.
• Schneider Electric, "ANSI® C37 Standard and UL® 489 Standard Comparison", Schneider Electric, Data Bulletin No. 0613DB9902, June 1999, Cedar Rapids IA, USA, retrieved 3 Apr 2015, original source: http://static.schneider-electric.us/docs/Circuit%20Protection
  /Insulated%20Case%20Circuit%20Breakers/0613DB9902.pdf
  Excerpts:
  
  The scope of the UL 489 Molded Case Circuit Breaker Standard includes miniature circuit breakers (MCBs), molded case circuit breakers (MCCBs) and insulated case circuit breakers (ICCBs).
  
  These circuit breakers are typically rated 10–6000 A and up to 600 Vac and 500 Vdc. Circuit breakers designed and tested to this standard typically exhibit the following characteristics:
  Sealed molded case
  Little or no maintenance
  No user replaceable parts
  Good performance and reliability
  Long service life
  ...
  The scope of the ANSI C37 Low Voltage Power Circuit Breaker Standard includes 2- or 3-pole stationary and drawout circuit breakers. The specifications of these circuit breakers are 254, 508 or 635 Vac maximum, fused or unfused, and manually- or power-operated with or without electromechanical or electronic trip units.
  
  These circuit breakers typically exhibit the following characteristics:
  Iron frame—older designs are open, newer designs are closed
  Maintainable for long service life
  Most parts can be replaced in the field
  High performance and reliability
  High maintenance costs
  ...
  The main construction differences between UL 489 Listed and ANSI C37 Certified circuit breakers are maintainability, ampere interrupting ratings (AIRs), heat rise and endurance. These construction differences result from the design and test philosophies outlined above.
  
  These differences will be discussed under Performance Testing. UL 489 Listed circuit breakers are sealed and require no maintenance for a long service life.
  
  ANSI C37 Certified circuit breakers typically require maintenance for long life and have been designed with an open case to facilitate maintenance.
• Smith, Linda., and Dennis McCoscrie,RESIDENTIAL ELECTRICAL DISTRIBUTION SYSTEM FIRES [PDF ] (1987), U.S. Consumer Product Safety Commission. [Online]. - local backup copy saved as CPSC-Glatz-to-CPSC-1-April-1988.pdf
  
  Cover letter excerpt:
  This report, the result of the Fire Investigation Project in the Electrical Hazards Program, provides estimates of fires associated with residential electrical distribution systems and a detailed discussion of identified causes. It describes 149 investigations performed by local fire services in sixteen cities over the periods 1980-1981 and 1984-1985.
  
  It was estimated that 56,300 residential fires involving the elec- trical distribution system, attended by the fire services, occurred annually during the period 1980-1985. These fires resulted in an estimated 410 deaths and 1,500 injuries annually. In addition, an estimated 890,000 residential fires involving the electrical distribution system, not attended by the fire services, occurred in 1984.
  
  The conclusions of this report indicate that new initiatives will be needed to effect significant reduction of these residential electrical fires. The majority of fires studied involved one or more serious violations of the National Electrical Code. Typically, no elec- trical inspection had been made for several years. The report recom- mends several possible activities involving state and local authorities to address the sources of most fires reported in the study. The Electrical Hazards Program plans to submit a FY 1990 project to address these fires.
  
  Two current Electrical Hazards Program projects focus on products, appliance cords and receptacles, that were involved in many of these fires. Both projects, however, are directed at improving voluntary standards for new products rather than replacing or identifying hazards involving older products that are already installed.
  
  Excerpt from CONCLUSION
  
  Available data indicate that fires in electrical distribution systems contribute significantly to the U.S. fire problem, accounting for a consistent portion of that problem, year after year. These fires are notoriously difficult to evaluate accurately because of the complexity of the electrical system and the difficulty of identifying details once a destructive fire has occurred. As discussed earlier, the investigations included in this this effort were not a controlled sample. Therefore, the possibility for bias in selection must be considered. For example it is possible that the fires not investigated had different causes. Even so, it seems reasonable to assume that the causes identified here depict some major part, even if not the whole, of the electrical distribution system fire problem.
  
  Three major characteristics were identified by this effortinadequate electrical system capacity, consumers' inappropriate actions to modify or accommodate that inadequacy, and construction of improper initial installations.
  
  The conclusion goes on to suggest possible ways to reduce the incidence of these electrical fires.
• Sprague, Michael, J., "Service-Life Evaluations of Low-Voltage Power Circuit Breakes and Molded-Case Circuit Breakers", Michael J Sprague Member, IEEE Cutler-Hammer, Inc. 130 Commonwealth Drive Warrendale, PA 15086 USA, retrieved 3 April 2015, original source: http://www.eaton.eu/ecm/groups/public/@pub
  /@electrical/documents/content/ct_129977.pdf
  Abstract
  
  This paper summarizes the methods that are typically used in industry to evaluate the service life of low-voltage power circuit breakers and molded case circuit breakers.
  
  It reviews the electrical ratings and endurance requirements set forth in manufacturing standards, the ways that these endurance requirements can be used to develop expectations of circuit breaker life, the methods of maintenance inspections and the interpretations of these inspections.
• Steel, J. G. "Statistical model for single-unit and multiunit circuit breakers." In Proceedings of the Institution of Electrical Engineers, vol. 119, no. 4, pp. 488-492. IET Digital Library, 1972.
• 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.
  Abstract:
  
  A wide range of data is presented which shows that the electrical performance of high-voltage a.c. circuit breakers is statistical.
  
  The electrical performance cannot be characterized by a single stress level such as a rated stress; a stress ratio is also required to specify the spread of operating conditions over which both clearances and failures occur fairly often. Present test specifications are inadequate to ensure that a circuit breaker is reliable on the basis of the formal tests alone.
  
  Calculations are presented relating the failure rate of a multiunit circuit breaker to that of its separate units. Suggestions are made for improved test strategies in which the present three shots on a multiunit circuit breaker could be supplemented by unit tests to predict a safe rating for the complete circuit breaker.
• UBI FPE CIRCUIT BREAKER TEST RESULTS [Web article] independent test results on UBI circuit breakers used to replace FPE Stab-Lok® circuit breakers find high failure rates.
  
  Also see
  UBI FPE CIRCUIT BREAKER VENDOR COMMENTS [Web article] OPINIONS & discussion of the safety of replacement circuit breakers sold for use in FPE Stab-Lok electrical panels
• UL 67, UL Standard for Safety for Panelboards, Underwriters Laboratories Inc., Northbrook IL 60062: UL
• UL 489, "Molded-Case Circuit Breakers, Molded-Case Switches, and Circuit Breaker Enclosures", Regulatory Services Department UL 333 Pfingsten Road Northbrook, IL 60062 ulregulatoryservices@us.ul.com 800-595-9844, retrieved 3 April 2015, original source: http://ulstandardsinfonet.ul.com/scopes/scopes.asp?fn=0489.html
  Excerpt:
  
  The requirements of this standard cover molded-case circuit breakers, circuit breaker and ground-fault circuit-interrupters, fused circuit breakers, high-fault protectors, and high-fault modules.
  
  These circuit breakers are specifically intended to provide service entrance, feeder, and branch circuit protection in accordance with the National Installation Codes in Annex B, Ref. No.1. This standard also covers instantaneous-trip circuit breakers (circuit interrupters) specifically intended for use as part of a combination motor controller in accordance with the National Installation Codes in Annex B, Ref. No. 1.
• UL, "Molded Case Circuit Breakers", (2012) Regulatory Services Department UL 333 Pfingsten Road Northbrook, IL 60062 ulregulatoryservices@us.ul.com 800-595-9844, retrieved 3 April 2015, original source: https://www.ul.com/global/documents/offerings/perspectives/regulators/
  electrical/newsletters/MoldedCaseCircuitBreakersMG.pdf
  Preface:
  
  UL has developed the Molded-Case Circuit Breaker (MCCB) Marking Guide for electrical inspectors, electric utilities, contractors, installers, users, designers, and other interested parties to aid in understanding MCCBs and the applicable codes and standards in order to facilitate a reasonably safe and code-compliant installation of MCCBs.
  
  These circuit breakers are intended to be installed in accordance with the National Electrical Code® (NEC ®) and their listing. These markings are required by UL 489, and are part of the listing.
• Wiermann, T.E., Rasmuson, D.M., Stockton, N.B., "Common-Cause Failure Event Insights: Circuit Breakers", Idaho National Engineering & Environmental Laboratory, U.S. Nuclear Regulatory Commission, Office of Nuclear Regulatory Research, Washington DC 20555, NUREG.CR-6819, Vol., 4, INEEL/EXT-99-00613, retrieved 3 April 2015, original source: http://pbadupws.nrc.gov/docs/ML0317/ML031710861.pdf
  Abstract:
  
  This report documents a study performed on the set of common-cause failures (CCF) of circuit breakes from 1980 to 2000. The data studied here were derived from the NRC CCF database, which is based on US commercial nuclear power plant event data.
  
  This report is the result of an in-depth review of the circuit breaker CCF data and presents several insights ab out the circuit breaker CCF data.
  
  The objective of this document is to look beyond the CCF parameter estimates that can be obtained from the CCF data, to gain further understanding of why CCF events occur and what measures may be taken to prevent, or at least mitigate the effect of, circuit breaker CCF events.
  
  This report presents quantitative presentation of the circuit breaker CCF data and discussion of some engineering aspects of the circuit breaker events. [copy on file]
  
  [This report lists 119 individual circuit breaker failures including failure to open or failure to close and attempts to explain the causes involved. e.g. item 49 among failure data:
  
  "One 4160 Vac circuit breaker failed to open and several more were degraded due to hardened grease and lack of lubrication. This problem could affect the ability of the subject breakers to open or close. Maintenance of the breakes was incomplete despite similar failures due to the same cause four years earlier."
• Yacout, A. M., R. N. Hill, L. Van Den Durpel, P. J. Finck, E. A. Schneider, C. G. Bathke, and J. S. Herring. "Dynamic analysis of the AFCI scenarios." Growth 400000 (2004): 500000.
• ZINSCO SYLVANIA ELECTRICAL PANELS [Web article] electrical, fire, and shock hazards associated with Zinsco electrical components, circuit breakers, electrical panels, including certain Sylvania electrical panels and breakers which are in fact of the same product design and origin.
• ZINSCO CIRCUIT BREAKER TEST REPORT [Web article] limited testing of Zinsco® circuit breakers by an independent expert reports a high failure rate for Zinsco circuit breakers

Other critical electrical system failures that are directly or closely related to individual circuit breaker brands, models, or wiring practices are explained and photo-documented at the live-linked articles just above.

Contributing Authors

• 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.
  
  See ALUMINUM WIRING BIBLIOGRAPHY
  
  and FPE HAZARD ARTICLES, STUDIES,
  
  and BACK-WIRED ELECTRICAL DEVICES
  
  also CIRCUIT BREAKER FAILURE RATES - you are on thi s page
  
  and UBI FPE CIRCUIT BREAKER TEST RESULTS
  
  also ZINSCO FAILURE REPORTS for examples.
• David W. Carrier, electrical engineer, Poughkeepsie, NY 12603 845-430-7527 davidwcarrier@earthlink.net. Mr. Carrier has conducted failures testing on electrical circuit breakers and panel assemblies, supplementing Dr. Jes Aronstein's research into FPE and other circuit breaker performance of other brands such as GE, ITE, Murray, Siemens, Bulldog Pushmatic, Zinsco.