Photograph of  this overheating and improperly-made aluminum to copper pigtail splice. How to repair aluminum wiring: recommended methods
How to Reduce the Risk of Aluminum Wiring Fires

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How should aluminum electrical wiring be repaired?

This article describes the immediate safety steps needed in a building where solid conductor aluminum electrical wiring is installed. This article describes the acceptable methods to repair aluminum wiring, including which aluminum wire connectors to use for safest results.

We describe how to make aluminum to copper pigtail connections using the COPALUM connector or the AlumiConn™ connector as well as how to make aluminum-to-aluminum wire connections and aluminum ground wire connections.

How to reduce the risks associated with aluminum electrical wiring - a practical guide shows which aluminum wiring connectors can be used successfully to connect aluminum conductor wires to copper-wired devices (such as lighting fixtures or fans) and to electrical receptacles ("plugs") or to light switches.

Notes on using the COPALUM connector for aluminum wire repairs - aluminum to copper pigtailing. Notes on using the AlumiConn™ connector for aluminum wire repairs - aluminum to copper pigtailing & aluminum to aluminum wire splices - where to buy and how to install and torque the AlumiConn aluminum wire repair connector. How to splice aluminum-to-aluminum electrical wires.

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.

HOW TO REDUCE THE RISK of Fire and Electrical Circuit Connector Overheating in buildings with Aluminum Electrical Wiring

Photograph of ALUMINUM WIRE in a junction box.The page top photograph shows an infra-red photo of an overheating aluminum wiring connection at an improper aluminum-to-copper "pigtail" splice (courtesy of G. Cohen).

Aluminum wire connections can overheat enough to start a fire without ever drawing enough current to trip a circuit breaker, and improper repairs can increase the hazard.

Immediate Actions for Safety of Aluminum Wiring

How to Repair Aluminum Electrical Wiring to Reduce the Hazards - Repair Alternatives & Choices

Once the initial steps above have been addressed here are the US CPSC recommended choices for safe repair of aluminum wiring:

Aluminum Wiring Repair Method No. 1: Re-wire the Building, Replacing All Aluminum with Copper Wire

Re-wire the Building replacing all aluminum branch circuit wiring with copper, as a "best repair method" for aluminum wiring. However this approach will be the most costly method for aluminum wire repair, requiring snaking new wires throughout the building.

New copper wires are run throughout the building, from the electrical panel to junction boxes, receptacle boxes and to connected devices such as electrical switches, receptacles (outlets or "wall plugs"), etc.

The old aluminum electrical conductors can be left in place in building walls and ceilings, and will be harmless once those wires are completely disconnected from the electrical system.

The re-wire approach to aluminum wiring repair is used principally when other building renovations that require opening building walls, ceilings, floors, make this method practical.

Aluminum Wiring Repair Method No. 2: Copper Pigtailing using the COPALUM Connector

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

COPALUM Copper-to-Aluminum Pigtailing Use the special AMP (now TYCO) COPALUM 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.

This "copper pigtailing" procedure is performed by an electrician trained and licensed by AMP or TYCO to use this COPALUM procedure. The TYCO COPALUM connector method and its pro's and con's are discussed here (below). The installation procedure for this connector is given in TYCO's instructions and is illustrated in precise detail by Aronstein at PIGTAILING USING AMP "COPALUM" CONNECTORS.

Typically this approach costs about half that of completely re-wiring a home with copper. Also see ALUMINUM WIRE REPAIR SPLICE SPACE.

A brief US CPSC article COPALUM ALUMINUM WIRE CONNECTORS discusses how to get these aluminum wire connectors.

TYCO currently leases the crimp tool necessary for making COPALUM repairs, and training is needed to use it properly. For photos of the TYCO COPALUM "Retermination Kit" - the crimping tool used to install COPALUM connectors on aluminum wiring, see this TYCO COPALUM Tool document. (PDF)You'll see that the tool is large, making work in tight quarters a challenge, especially if the original lengths of wire to be pigtailed are short.

You'll also read in Tyco's DRAFT CONTRACT from TYCO for electricians that TYCO considers "old technology" aluminum wire to be unsafe, but in fact later-installed "new technology wire" performs about the same. Both "old technology" and "new technology" solid conductor aluminum wire alloys varied from manufacturer to manufacturer, some performing better or worse than others.

How to Become a Certified COPALUM Installer for Aluminum Wiring Repairs

The following material is based on information from Tyco Electronics, supplier of the COPALUM connector and crimping tool used for aluminum wiring repair:

Becoming a Certified COPALUM Installer - Certification Procedure 

  1. Review, sign and return the contract for the COPALUM Retermination Program.*
  2. Contact a participating local Electrical Distributor for availability and delivery of the COPALUM Retermination Tool.
  3. Contact Tyco Electronics to set up a training date for certification training.
  4. Certification Card is provided after completion of training for the purchase of product.

*Refer to Terms & Conditions Document concerning contract specifics
Tool Leasing:

Pricing and availability only through a participating Electrical Distributor

  1. Tooling: Lease only option (Tool is NOT available for sale)
    1. 3 month minimum lease — Contact a participating Electrical Distributor for pricing.
    2. Monthly Fee — Contact Electrical Distributor for pricing.
  2. Certification Training is provided by Tyco Electronics Field Service Specialist.
    1. Training consists of 2 to 4 hour instruction for tool use & connector application.
    2. Training Cost - $ 750.00 plus travel & expense (Limited to 6 participants).

Once contractor has tool availability date from distributor, contact Tyco Electronics to schedule training date.

Contact Tyco Electronics customer service for additional information at 800.468.2023.
Contractors can identify distributors in their area by contacting 1-800-527-6686.

See Tyco Electronics for details about COPALUM certification, crimping tool leasing, supplies, training. Terms and conditions of leasing the COPALUM retermination tool (crimping tool) for aluminum wire repairs includes requiring that the contractor be properly trained in use of the equipment.

Tyco COPALUM Part Numbers

Shortcomings of the COPALUM Aluminum Wiring Repair Method

Space limitations in the junction box or receptacle box: These connectors and the copper pigtail wires take up more space in a junction box or receptacle box than the original wires and connectors. at ALUMINUM WIRE REPAIR SPLICE SPACE we discuss options for fitting the COPALUM connector and pigtail wires into electrical boxes where space is tight.

OPINION: Problem for Large Electrical Contractors repairing aluminum wiring: Tyco should make the COPALUM crimping tool available for sale:

Unfortunately, Tyco's "rent-only" option for the COPALUM connector makes aluminum wiring repair service prohibitively expensive for large electrical repair companies who are performing extensive aluminum repair work in large urban areas.

Placing multiple repair tools in multiple repair service trucks with aluminum-wire repair-trained experts, and keeping them there year in and year out in order to be responsive to consumer needs prices this service right out of that market place and has tempted some aluminum repair electricians to make use of alternative repair methods that appear to work (the AlumiConn discussed below) and other aluminum repair methods that have been shown to be ineffective and dangerous.

OPINION: Problem for Small Electrical Contractors repairing aluminum wiring:Tyco should make the COPALUM crimping tool available for short term rental: 

A small electrical contractor wanting to become trained, certified, and qualified to perform a small number of aluminum wire repairs faces a different problem. Tyco rents the COPALUM crimping tool for a three-month minimum, converting to a month-to-month lease thereafter.

This will not be economical for a small contractor performing only occasional aluminum wiring repairs.

Aluminum Wiring Repair Method #3 - the AlumiConn™ Alternative has U.L. Listing & Approval

AlumiConn torque tests by D Friedman (C) Daniel Friedman AlumiConn TM aluminum to copper lug connectors[1] [New in 2006, U.L. Listed, 2007 completed independent testing, CPSC recommended 2011] available from King Innovation.

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".

AlumiConn TM Purple #95135 aluminum to copper lug connectors [New in 2006, now U.L. Listed, 2007 completed independent testing] available from King Innovation. The AlumiConn connector is now recommended for aluminum wiring repairs - US CPSC.

The AlumiConn™ connector shown here is used to splice a copper "pigtail" wire together with one or two aluminum wires as a step in reducing the fire hazard associated with aluminum electrical wiring.

This connector performs well provided that the wires are properly secured in the connector, and it has been included in the US CPSC recommendations for aluminum wiring repair.

Reference: details of the study and recommendations are on page #6 (the 9th page in the .pdf file) in Dr. J.A. Aronstein's .pdf document version of "Reducing the Fire Hazards in Aluminum Wired Homes" May 21, 2007. The test results are completed and will be published in September 2007. (100 connectors cost $285. Lower prices for larger quantities.)

Alumi-Conn where to buy, how to install: 

How to Install the AlumiConn aluminum wiring repair connector

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

Installation instructions for AlumiConn™ for aluminum wiring repair

AlumiConnTM Status Update - CPSC Recommended

Question: Is it OK to Use the AlumiConn™ by King Innovation for Aluminum Wiring Repair

In the section regarding aluminum wiring repair it is not clear to me if the product called Alumiconn by King Innovation is a safe and acceptable alternative to Copalum. I have not been able to find anywhere in the internet any further references to how safe is this product beyond the publication by J. Aronstein last update July 6, 2007. Can you clarify this for me? - J. C., Orlando, FL

[Note: this question and answer was posed in 2009 but has been updated to reflect the 2011 US CPSC recommendations concerning the AlumiConn connector - Ed.]

Answer: Yes, properly installed this is an approved repair for aluminum wiring.

Safety/Usability of the AlumiConn™: 4 Points of Discussion

1. Independent tests showed that IF the Alumiconn connector is properly installed (including torquing to the proper torque setting) it performs as well as COPALUM. We have absolute confidence in Dr. Aronstein in this matter - he is fully qualified, experienced, and is an unbiased independent party with no financial connection to the company selling Alumiconn (nor to any one else selling other products).

Here is Aronstein's paper on the topic: Reducing the Fire Hazards in Aluminum-Wired Homes - 5/21/07, (AlumiConn™ info is on p. 9)

The Alumiconn™ is UL listed (UL 486C) as a "pressure type screw connector" (USA) and CSA approved (Canada) for aluminum wiring repairs.

For general information about that listing type, see this UL connector information On the UL listing for wire connectors.

2. U.S. CPSC: This connector performs well provided that the wires are properly secured in the connector, and it has been included in the US CPSC recommendations for aluminum wiring repair as of approximately June 2011.[2][3]

3. Torque settings for the AlumiConn™: Reading the UL document we see no mention whatsoever of torque specifications - those are particularly important for this particular connector as it involves tightening a screw in a terminal block to secure the aluminum or copper wire being spliced.

Aronstein emphasized that the connector's acceptable performance relied on using the proper torque settings.

AlumiConn torque tests by D Friedman (C) Daniel Friedman

Torque settings are described at Technical notes on Installing or Wiring the AlumiConn™ The "alternative method" described by the manufacturer for tightening the screws produces torque close to or exceeding the actual torque specified numbers (according to some preliminary tests we have done in our lab) - photo at left.

4. UL listing vs CPSC Recommended: So if you were working for someone else and wanted to install only the CPSC-recommended connectors, you'd use only the AMP/TYCO COPALUM™ method or the AlumiConn™.

In March 2010, prior to the CPSC recommendation of AlumiConn™ connectors for aluminum wiring repairs, we (DJF) presented this information for a group of 50 licensed electricians at an Aluminum Wiring Repair Methods Update - class in Dallas TX.

These were trained licensed electricians who are informed and conservative in their practice.

The company's position was that they would not use an connector that was not CPSC-recommended, notwithstanding its UL listing. Indeed, some products carrying a UL listing for aluminum wiring repair have been shown to perform very poorly in the field, such as CU/AL devices and the Ideal65 purple "Twister" connector sold for that purpose.

How to Repair Aluminum-to-Aluminum Wire Splice Connections

Photo of aluminum to aluminum wire splicing before repair

Aluminum to aluminum wire splices also need to be repaired in an aluminum-wired home. These splice connections are typically found in junction boxes (shown below) but may also occur in some receptacle boxes where a device such as a light or electrical receptacle are also wired.

Traditionally these splices were made with twist-on connectors - an approach shown below (left) and one that is unsafe (below right) because of the risk of overheating and a potential for fire.

Our photograph at above left shows aluminum wire spliced to aluminum wire at a connection which had not overheated when we took this photo.

Photo of aluminum to aluminum wire splicing after an improper repair

The photograph at left severe overheating and burn-up of an aluminum to copper splice made using a conventional twist-on connector.

Avoid Using Copper Pigtails When Splicing Multiple Aluminum Wires Together

The various "copper pigtailing" methods discussed in articles on aluminum wire repairs (at aluminum-wired devices such as electrical receptacles, switches, and lights) are not the best approach when repairing aluminum-to-aluminum wire splices such as at a junction box in a building (where several aluminum-wire circuits or wires are joined together).

Which Connectors Are Used for Splicing Aluminum Branch Circuit Wires

AlumiConn torque tests by D Friedman (C) Daniel Friedman

For the aluminum wire to aluminum wire connector case, use of a splicing connector whose manufacturer specifies that the connector must be used with a combination of copper and aluminum wires together (the COPALUM) makes little sense.

Our photo left shows three aluminum wires connected together (spliced) into an AlumiConnTM device.

For the small aluminum wire sizes such as found in building branch circuit wiring for lighting and receptacles, the AlumiConnTM is probably the best choice if the COPALUM connectors and special crimping tool are not readily available.

The installation instructions for the AlumiConnTM (AlumiConn INSTALLATION PROCEDURE) indicate that the connector can be used for splicing solid conductor aluminum branch circuit wires in sizes #12 - #10.

Overheating aluminum wire (C) Daniel Friedman

For larger aluminum wire sizes sizes (stranded aluminum wiring such as found at air conditioning compressor circuits, electric range circuits, clothes dryer circuits and other high-amp devices), any of the (UL listed for Aluminum) setscrew type connectors in combination with the inhibitor/abrasion installation technique should suffice.

Since we've seen frequent field reports of overheating at multi-strand high-amp aluminum wired devices such as air conditioning compressors, it is important to address these cases by proper repair methods.

[Note: some air conditioning equipment manufacturers currently recommend use of only copper wiring to feed their equipment - DJF June 2007]

Photo of the WALL-NUT aluminum wire lug connector sold by WAGO
WALL-NUTS [New U.S. product application, Not UL Listed, undergoing testing before UL application] spring-clamp terminal blocks available from Wago Corporation have is being tested by that company for a connector for aluminum-to-copper pigtailing for aluminum wiring repair. The company informs us that a similar product use with aluminum wire conductors has been approved and used in Europe for over 20 years.

The company is conducting further testing before submitting the product to UL to obtain a listing. Significantly, the company indicates that this connector is suitable for connecting multi-stranded (copper) as well as solid conductor conductors. If approved by UL and if test results are satisfactory, this product would, in addition to providing standard solid CU to solid AL connections, address the wiring of a twisted-copper-wire light fixture to a solid conductor aluminum branch circuit wire.

This connector has not been recommended, nor recommended against, by the US CPSC, and is currently undergoing testing. Results will be reported here ASAP. Product description information for the copper to copper wire connection use of this connector is available at the Wago website.

Other Approaches to the Repair of Aluminum Electrical Wiring

Other aluminum wiring repair connector products have been sold by various manufacturers, some with good performance and some unacceptable. Descriptions are below. Emergency temporary repairs necessary to keep an essential circuit in service might be possible following other procedures described by the CPSC or by industry experts.

Details about other aluminum wire repair methods that are not recommended are found at ALUMINUM WIRING REPAIR 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" aluminum wire splice connector shown in the photo at left (12 connectors cost $49. to $79.)

Note: The instructions for this connector require that it always include a copper pigtail when making aluminum wiring connections - a condition impractical for splicing aluminum-to-aluminum wires.

Repairing aluminum lighting wiring (C) Daniel Friedman

Other methods - also not recommended: include attempts to repair aluminum wiring using 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?). COALR and CU/AL devices as a "repair" for aluminum wiring is discussed at ALUMINUM WIRING REPAIR, Other Products.


Continue reading at AlumiConn INSTALLATION PROCEDURE or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.


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