Overheating aluminum electrical wires starting a fire (C) Jess Aronstein The Aluminum Wiring Hazard & Repair Website

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Aluminum Electrical Wiring Hazards & Aluminum Wiring Repair Methods:

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.

Aluminum Electrical Wiring Dangers, History, & Repair Procedures

Photograph of overheating aluminum-wired electrical outlet

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.

Problems 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.

Photograph of overheating aluminum-wired electrical outlet

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 circuits.

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.

Photograph of  this overheating and improperly-made aluminum to copper pigtail splice. Photograph of this overheating and improperly-made aluminum to copper pigtail splice.

The AMP TYCO COPALUM Connector for Aluminum Wiring Pigtailing Repairs

Photo of the AMP COPALUM aluminum wiring connector recommended by the US CPSC

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 AMP (originally TYCO) COPALUM connector method is described is described in detail

COPALUM ALUMINUM WIRING CONNECTOR AVAILABILITY discusses how to get these aluminum wire connectors

The AlumiConn™ Aluminum Wiring Connector for Pigtailing and Repairs

Photo of the AlumiConn aluminum wire lug connector sold by King Innovations

AlumiConn TM Purple #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".

Alumi-Conn where to buy, how to install: 

Obsolete Aluminum Wiring Repair Method - No Longer Recommended

Photo of the 3M Scotchlok wiring connector which can be used for aluminum wiring repairs, has tested successfully but has not been recommended by the US CPSC

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.

A summary of this method is at "Scotchlok 3M connector" and details of this method are at Aluminum Wire alternative repair: Special Aluminum Wire Repair Method

Other Aluminum Wiring Repair Methods that Are Not Recommended

Photo of the Ideal 65 purple twister aluminum wire connector which is NOT RECOMMENDED

Other methods - not recommended: Warnings regarding other "repair" methods which are not recommended are discussed

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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Aluminum Electrical Wiring Information you CAN copy to your website: for information on aluminum electrical wiring that can be copied to your website, see Aluminum Wiring Summary Page for Public Use.

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Aluminum Electrical Wiring Articles

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