Inadequate Contact Between Aluminum Conductors in Twist-On Connectors
Color photos and descriptive captions from CPSC Meeting 9/28/95.
In this document aluminum wire twist-on connector failures and repair procedures are described,
including aluminum wire repair methods which work and methods which do not work and are unsafe. This document series describes hazards with existing aluminum wiring repair products, explains the aluminum wiring failure mechanism,
and reviews recommended retrofit procedures including use of readily-available materials.
This information was presented to the US Consumer Product Safety Commission by Dr. J. Aronstein, 9/28/95. The minutes of that meeting were obtained under the Freedom of Information Act and posted by Daniel Friedman January 1996.
Click any image to see an enlarged version.
17. The characteristic heating in a band around the connector shows us where the heat is being generated. In all of those failures shown, from both lab and homes, the heat is generated by current
flowing in the connector spring. Here, all of the current is passing from wire-to-wire through sections of the steel spring.
18. Current flow in the steel spring occurs due to a fundamental deficiency in this type of connection when made with aluminum wire. There is inadequate metallic contact directly established from
wire-to-wire. The insulating oxide on the aluminum is not sufficiently broken up. (Photo: connector removed after splicing.)
19. The amount of twisting together of the wires varies substantially with the hardness, size(s), and number of wires installed. Inadequate mechanical disturbance results in poor electrical contact at
the wire-to-wire interface. This is a fundamental deficiency of twist-on connections with aluminum wire.
No FAQs have been posted for this page. Try the search box below or CONTACT US by email if you cannot find the answer you need at InspectApedia.
Ask a Question or Search InspectApedia
Questions & answers or comments about the failure of connectors used in aluminum wiring repairs.
Use the "Click to Show or Hide FAQs" link just above to see recently-posted questions, comments, replies, try the search box just below, or if you prefer, post a question or comment in the Comments box below and we will respond promptly.
 "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
 Thanks to reader Thomas Kremer
for suggesting clarification to this topic 08/09
 Personal communication, Email, P. King to D Friedman, 3/10/2012 [copy on file AlumiConn_PK120310.pdf].
Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair
The Home Reference Book - the Encyclopedia of Homes, Carson Dunlop & Associates, Toronto, Ontario, 25th Ed., 2012, is a bound volume of more than 450 illustrated pages that assist home inspectors and home owners in the inspection and detection of problems on buildings. The text is intended as a reference guide to help building owners operate and maintain their home effectively. Field inspection worksheets are included at the back of the volume. Special Offer: For a 10% discount on any number of copies of the Home Reference Book purchased as a single order. Enter INSPECTAHRB in the order payment page "Promo/Redemption" space. InspectAPedia.com editor Daniel Friedman is a contributing author.
Or choose the The Home Reference eBook for PCs, Macs, Kindle, iPad, iPhone, or Android Smart Phones. Special Offer: For a 5% discount on any number of copies of the Home Reference eBook purchased as a single order. Enter INSPECTAEHRB in the order payment page "Promo/Redemption" space.
ALUMINUM WIRE REPAIR METHODS to reduce risk in buildings with Aluminum Electrical Wiring - Overview of Acceptable Repair Practices (in the document you are presently viewing)
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: