this Aluminum Wiring Website answers just about any question concerning aluminum electrical wiring, aluminum wiring failure causes, cures, repairs, and prevention. We include authoritative, expert aluminum wiring failure research, field failure reports, and descriptions of approved aluminum wiring repair procedures and products.
At page top, an illustration from a research report by Dr. Jess Aronstein illustrates how aluminum wire electrical connections overheat to start a fire. At the point shown in Aronstein's photograph, the twist-on connector is completely burned but the electrical fire continues, having ignited the plastic jacket of the wire insulation and the cable jacket end.
In the wall of an actual building, this fire may spread outside of the electrical box, or it may not, depending on the actual environment and what combustible materials are close to the electrical box. Aronstein concludes that in any event, the inside of an electrical box in a building is no place for burning materials.
We also provide a MASTER INDEX to this topic, or you can try the page top or bottom SEARCH BOX as a quick way to find information you need.
This website describes the hazards and remedies for aluminum electrical wiring - a fire hazard in homes. We provide complete and authoritative research, technical information, description and explanation of why solid conductor branch circuit wiring of aluminum is unsafe, and we describe both proper and improper repair methods for aluminum electrical wiring.
Watch out: unless it has been repaired properly, solid-conductor aluminum electrical wiring, installed in homes in North America in the 1960's and 70's is a fire hazard in buildings. Aluminum electrical wire was never "recalled" in the U.S. nor in Canada. The absence of a product recall is not an assurance that it is safe.
Aluminum electrical wiring is indeed "safe" in buildings if it has been properly repaired using methods and connectors described at this website.
[Click to enlarge any image]
Just how safe is un-repaired aluminum wiring? According to the U.S. Consumer Product Safety Commission, fires
and even deaths have been reported to have been caused by this hazard.
Mis-information about aluminum wiring is widespread and its failure mechanism leading to overheating is usually not explained properly.
due to aluminum wiring expansion, or much more likely micro-fretting and arcing at the aluminum wiring connectors,
can cause overheating at the connections between the wire and
devices (switches and outlets) or at aluminum wire splices.
The connections can become hot enough
to start a fire without ever tripping a circuit breaker!
The photos shown at left and just below are not the most dramatic catastrophes linked to fires caused by aluminum wiring.
But these are conditions that are found in many homes with aluminum wiring, confirming that this is a real, common, and widespread hazard.
CPSC research shows that "homes wired with aluminum wire manufactured before 1972 are 55 times more
likely to have one or more connections reach "Fire Hazard Conditions"
than are homes wired with copper.
"Post 1972" aluminum wire is also a concern. Introduction of the aluminum wire
"alloys" in 1972 time frame did not solve most of the connection failure problems.
Aluminum wiring is still permitted and used for certain
applications, including residential service entrance wiring and single-purpose higher amperage circuits such as 240V air conditioning or electric range
The fire risk from single purpose circuits is much less than for branch circuits.
But it's not necessarily because of a "new alloy" as some folks assert. It's because there are
enormously fewer connections (four or six rather than 30 or 40 per circuit) and thus statistically a smaller chance of a connection failure. These connections do still
burn up, as indicated by field reports.
List of Key Articles on Aluminum Wiring Hazards & Repair Methods
Photos below show an improper aluminum-to-copper pigtail splice which is overheating, and an infra-red photo of the
same connection, from a more distant view (courtesy of G. Cohen). Aluminum wire connections can overheat enough to
start a fire without ever drawing enough current to trip a circuit breaker.
ALUMINUM WIRING HAZARDS & REPAIRS The Aluminum Wiring Website - home page, describing the hazards of & repairs for aluminum electrical wiring, including authoritative, in-depth information, photographs, documents. You are on the aluminum wiring website main page.
ALUMINUM WIRE AlumiConn - terminal block type connector recommended by the US CPSC for aluminum wiring repair, an alternative approach to the COPALUM device: where to buy & how to install the AlumiConn connector for aluminum wiring repairs
Other Products, Ideal 65 Purple Twister (not recommended), & other Aluminum Wire Products/Articles (in the document you are presently viewing)
HOW TO IDENTIFY ALUMINUM WIRING, recognition photos of wire insulation, exterior and interior appearance, use in situ in electrical panels, junction boxes, and other clues indicating the presence of aluminum electrical wiring in buildings
05/21/2007 REDUCING the FIRE HAZARDS in ALUMINUM-WIRED HOMES - 2007 [PDF document], Jess Aronstein, Ph.D., 21 May 2007. This document answers most technical questions about the hazards and remedies of aluminum electrical wiring and includes
a report on independent test results of alternative products and methods for repairing aluminum wiring. Some of the sections of this very thorough document are listed below:
02/09/2006 REDUCING the FIRE HAZARDS in ALUMINUM-WIRED HOMES - 2006 [Web Page], Jess Aronstein, Ph.D., This older version of the above document also answers most technical questions about the hazards and remedies of aluminum electrical wiring
but lacks latest repair product testing such as the AlumiConn connector discussed above. Some of the sections of this very thorough document are listed below:
The AMP TYCO COPALUM Connector for Aluminum Wiring Pigtailing Repairs
AMP TYCO COPALUM Copper-to-Aluminum Pigtailing Use the special AMP (now TYCO) COPALUM high pressure crimp connector and special tool to connect short copper wires to every aluminum wire end in the building, reconnecting the copper to the various devices (outlets, switches, lights) and splices.
The AlumiConn™ Aluminum Wiring Connector for Pigtailing and Repairs
AlumiConn TMPurple #95135 aluminum to copper lug connectors [New in 2006, U.L. Listed, 2007 completed independent testing]
available from King Innovation.
The AlumiConn connector is now recommended for aluminum wiring repairs - US CPSC.
Results of independent testing indicate that this product "... is predicted to have a high probability of failure-free long-term safe performance,
PROVIDED THAT THE SETSCREWS ARE CAREFULLY TIGHTENED TO THE MANUFACTURER'S RECOMMENDATION".
ALUMINUM WIRE REPAIR SPLICE SPACE describes steps to gain sorely-needed wiring space when using the AlumiConn™ (or the harder to obtain COPALUM™) connector for the copper pigtail repair method for aluminum wiring, and this article also includes photographs of the steps in a reader's actual field installation experience using the AlumiConn splice connector.
The AlCopStore is an independent website where you can also purchase the AlumiConn™ aluminum wiring connector.
Obsolete Aluminum Wiring Repair Method - No Longer Recommended
Scotchlok 3M Special Method [- superceded by new alternate repair as of June 2007 -]: this ""Scotchlok 3M Special Method was previously recommended as independent tests showed that it performed acceptably.
While this repair method has been superceded by new alternate repair as of June 2007, we have kept this description available to aid home buyers, electricians and home inspectors who may discover or need to be able to recognize this aluminum wire repair method if it was previously used in the building.
such as the Ideal 65 purple "Twister" connector shown in the photo at left (12 connectors cost $49. to $79.), Marrette B-Cap ACS™ #63 AL/CU Twist-On Connectors, and electrical receptacles and outlets marked "COALR" (even if these worked, which has not been
demonstrated, what about all of the other electrical connections and splices in the building?) and others.
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InspectAPedia is an independent publisher of building, environmental, and forensic inspection, diagnosis, and repair information provided free to the public - we have no business nor financial connection with any manufacturer or service provider discussed at our website. We do not sell products nor services.
We are dedicated to making our information as accurate, complete, useful, and unbiased as possible: we very much welcome critique, questions, or content suggestions for our web articles. Working together and exchanging information makes us better informed than any individual can be working alone.
Continue reading at ALUMINUM WIRING IDENTIFICATION or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.
"Repairing Aluminum Wiring", US CPSC Publication 516, U.S. Consumer Product Safety Commission, Bethe3sda MD, website: www.cpsc.gov / www.SaferProducts.gov, updated June 2011, original source: .cpsc.gov/cpscpub/pubs/516.pdf, Quoting:
The U.S. Consumer Product Safety Commission (CPSC) staff and other government
have investigated numerous hazardous incidents and fires throughout the nation
involving aluminum branch circuit wiring. A national survey conducted by Franklin
Institute for CPSC showed that homes built before 1972, and wired with
are 55 times more likely to have one or more wire connections at outlets reach
“Fire Hazard Conditions”1 than homes wired with copper. That survey encompassed only
the wire connections at outlets. It did not address other types of aluminum wire connections
and splices in homes that are also prone to fail. No information was developed for
aluminum-wired homes built after 1972.
The fire hazard investigated by CPSC occurs at connections with aluminum wire, including
receptacles or switches and junction boxes; or the hazards occur with major appliances,
including dishwashers or furnaces, for example. There are several deterioration processes in
aluminum wire connections that cause increased resistance to the flow of electric current,
resulting in damage that is cumulative in effect. That increased resistance causes overheating,
sometimes at hazardous levels, when current is flowing in the circuit.
"Record of Commission Action, Commissioners Voting by Ballot", CPSC Publication No. 516, Repairing Aluminum Wiring (original version op.cit.), (Briefing package dated March 15, 2011), Quoting: The Commission voted unanimously (5-0)·to approve republication of CPSC Publication No. 516, Repairing Aluminum Wiring, with the explicit recognition that the COPALUM and AlumiConn connectors currently are the only products that meet the agency's standards to prevent aluminum wire fire hazards Copy on file as /aluminum/Pub516_Alumi_Conn.pdf
Dr. Jess Aronstein, firstname.lastname@example.org 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 see FPE HAZARD ARTICLES, STUDIES for examples.
"The Influence of Corrosion Inhibitor and Surface Abrasion on the Failure of Aluminum-Wired Twist-on Connections",
Aronstein, J.; Campbell, W.,
Components, Hybrids, and Manufacturing Technology, IEEE Transactions on
Volume 7, Issue 1, Mar 1984 Page(s): 20 - 24
"Overheating Failures of Aluminum-Wired Special Service Connectors", J. Aronstein and W.E. Campbell,
IEEE Transactions, Vol. CHMT-6, No. 1, March 1983.
This paper appears in: Components, Hybrids, and Manufacturing Technology, IEEE Transactions on
Publication Date: Mar 1983
Volume: 6, Issue: 1
On page(s): 8 - 15
Current Version Published: 2003-01-06. This paper is available to IEEE members and subscribers and can be obtained through public or academic libraries.
Abstract: Special service" twist-on connectors are tested with aluminum and copper wire combinations. The special service connectors are qualified by a Canadian standard which applies to connectors for use with aluminum branch circuit conductors. Two brands of special service connectors are presently qualified by this standard and marketed. Both are rated for various combinations of aluminum and copper conductors. Samples of both brands are tested in this investigation. The tests are conducted within rated electrical and environmental conditions, with connections made according to the connector manufacturers' instructions. Overheating failures have occurred among the aluminum-wired special service connector combinations. The failures are accelerated by humid environment to a greater extent than by the application of electrical current. In contrast, connections which are copper-wired, using either standard or special service connectors, are stable and failure-free. The difference between the standard twist-on connectors and the special service connectors is in the material used for the connector spring. Improved compatibility between the spring material and the aluminum conductor, compared to the plated steel springs of the conventional twist on connectors, has not dealt with several important failure mechanisms. The test results indicate that the new standard, as presently defined, cannot be relied on to screen out aluminum-wired connector combinations which will not survive long-term operation within rated conditions. Thus the objective of accelerated qualification testing-- the prediction and assurance of safe and reliable operation in actual service---is not achieved in this case. The reasons are discussed, along with possible improvements.
"Evaluation of a Twist-on Connector for Aluminum Wire", Dr. Jesse Aronstein, Forty-Third IEEE Holm Conference on Electrical Contacts, Jan 1997, 0-7803-3968-1/97.
[This article describes the Ideal Industries Ideal#65 purple "Twister" twist-on connector marketed as a repair/retrofit for residential aluminum wiring. --DJF]
Abstract: A new type of twist-on splicing component for use with aluminum
and copper wire combinations is tested to determine initial resistance, performance in a zero-current environment test, performance in a heat-cycle test, and portion of current carried by the connector's steel spring. The splices tested consist of two aluminum wires and one copper wire.
The aluminum wire samples used for the test are of the types actually installed in aluminum-wired homes. Initial resistance is found to be relatively high,
and there is a significant sample-to-sample variation. This reflects failure to consistently establish low-resistance wire-to-wire contact through the insulating oxide film on the wire. Results of the environmental and heat-cycle tests show deterioration of a significant portion of the samples.
The splices made with this connector are also found to be sensitive to mechanical disturbance, such as applied in
normal installation when the completed splice is pushed back in to the junction box. Based on the test results, it is concluded that this connector has not overcome the fundamental deficiency of twist-on connectors for use with aluminum wire applications. Keywords: aluminum wire, connectors, twist-on connectors, environmental test, heat-cycle test.
Thomas & Betts, 8155 T&B Boulevard Memphis, TN 38125 USA, is a producer of more than 30,000 electrical components. 888-862-3289. Quoting the company: Thomas & Betts offers more than 30,000 high-quality products marketed under a variety of market-leading brand names. Designed to help passively conduct electricity, Thomas & Betts products are found everywhere electricity is used -- inside commercial and industrial buildings, in homes and schools, inside complex machinery and original equipment, in the power generating plant and distribution network, outside your home and underground.
Recommended books on electrical inspection, electrical wiring, electrical problem diagnosis, and electrical repair can be found in the Electrical Books section of the InspectAPedia Bookstore. (courtesy of Amazon.com)
Aluminum Wiring Information Link code to paste to your website: Use these LINK EXCHANGE INSTRUCTIONS to request a listing and to exchange website links.
Reducing the Fire Hazards in Aluminum-Wired Homes , Jess Aronstein, Ph.D., This document answers most technical questions about the hazards and remedies of aluminum electrical wiring. Some of the sections of this very thorough document are listed below:
Electrical Panels, How to Inspect in buildings, safety for electrical inspectors, electrical panel, fusing, wiring defects, defective products. Inspection Class Presentation
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