Photograph of ALUMINUM WIRE  - Recognizing aluminum wiring may be possible where nonmetallic wiring is visible such as in attics or basements.How to Recognize or Identify Aluminum Electrical Wiring in buildings

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How to recognize or identify aluminum electrical wiring in buildings. This article provides tips and photographs helpful in identifying the presence of aluminum wiring in residential properties. Because we've had requests for help in identifying this wire we've included some tips.

Be sure to also look at other photographs available at the Aluminum Wiring Website as many of them show closeups of aluminum wire in various applications.

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How to Recognize or Identify Aluminum Electrical Wiring in Homes

Photograph of Aluminum wire in the
electric panelWatch out: unless you are specifically trained to do so, do not open or disassemble or touch any electrical panels, devices, components if you are not trained and competent. There is risk of fatal electric shock.

[Click to enlarte any image]

  • When was the house built or re-wired or when were circuits added? Homes built, rooms added, circuits rewired or added between 1965 and 1973 may contain aluminum wiring.
  • Don't assume that there's no aluminum wire if your house was not built during these years. Circuits may have been added, extended, modified using aluminum wiring. Or an installer may have had leftover aluminum wire and used it after these dates.
  • Photograph of Aluminum wire in the
electric panelAn electrician or home inspector qualified to open the electric panel will look at wire at circuit breakers in the panel for aluminum wire. The pen in the circled area points to bare silver-colored wire visible at the circuit breaker. Notice that the aluminum wire in this photo is a single circuit installed between two copper wires (on adjacent breakers).

    Also notice the bare wire exposed at the neutral bus. An easy place to look for aluminum wire than at the circuit breakers might be at the neutral bus where both white neutral wires and ground wires are connected in a row. There it's easier to see exposed portions of the wire itself.
  • Photograph of Kaiser Aluminum Wire
    Look for the word "Aluminum." Without opening any electrical panels or other devices, a homeowner or building inspector can still look at for printed or embossed letters on the plastic wire jacket where wiring is visible in the attic or at the electric panel. Some aluminum wire has the word "Aluminum" or a specific brand name such as "Kaiser Aluminum" plainly marked on the plastic wire jacket.
  • This photo shows a dark colored wire jacket with green print indicating "Kaiser Aluminum." Some white colored plastic wire jackets are inked in red; others have embossed letters without ink and are hard to read. Try shining a light along the wire
  • Don't assume there's no aluminum wire just because you find none in the panel. Aluminum may have been used for part of circuits or for some but not other circuits in the building.

  • At outlets and switches, look at stripped wire ends. Often simply removing the cover plate will give sufficient view. Be especially cautious if you see back-wired receptacles. It may be difficult to see if the wire is aluminum, but if it is, the smaller wire contact surface when this method was used may increase the risk of overheating or other failures.
  • In the attic look at the wire gauge or "size." Look for #12-gauge wires in the attic or other places where wiring is readily available. If you see only #12 and no #14, aluminum wiring may be present. Aluminum wire must be one wire gauge size larger for a given circuit than if copper was used.

    So while #14 copper wire is permitted on a 15-amp electrical circuit and since #14 copper wire branch circuits are common in homes, if aluminum wire was used for the same circuit it would have to be #12. Similarly, a 20-amp circuit uses #12 copper wire or #10 aluminum wire.

    Common residential lighting and electrical-receptacle circuits are 15-amp or possibly 20-amp (e.g. in a kitchen). So if you see only #12 or larger wires in the attic of your house look further to see if it's aluminum. The wire-gauge size is printed or embossed on the wire jacket. #12 does not guarantee it's aluminum, it's just more data to point in that direction.






  • Photograph of ALUMINUM WIRE in a junction box.
    Aluminum wires spliced together in this metal junction box has not overheated. It was exposed by an electrician. A homeowner should not be taking the risk of opening and exposing electrical wiring.



  • Photograph of aluminum splice to stranded copper in light fixture
    Aluminum wiring spliced to stranded copper wire in a ceiling light fixture was found during a wiring survey I performed - a common condition.




  • Photo of the AMP COPALUM aluminum wiring connector recommended by the US CPSC COPALUM Copper-to-Aluminum Pigtailing repairs may be observed in homes where this special AMP (now TYCO) COPALUM connector and special tool were used to connect short copper wires to aluminum wire ends in the building. The TYCO COPALUM connector method is described at PIGTAILING USING AMP "COPALUM" CONNECTORS Typically this approach costs about half that of completely re-wiring a home with copper.

    COPALUM ALUMINUM WIRING CONNECTOR AVAILABILITY discusses how to get the proper aluminum wire connectors
  • Photo of the AlumiConn aluminum wire lug connector sold by King Innovations AlumiConn connectors and aluminum wire aluminum to copper lug connectors used for pigtailing or splicing may be observed in homes where aluminum wiring repairs have begun after about June 2007.

    [New in 2006, U. L. Listed, 2007 completed independent testing], recommended by CPSC 2011.



  • Photograph of a non-recommended twist-on connector repair attemptThe Ideal 65 Purple Twister, A Not-Recommended "Repair" attempt for aluminum wiring using a twist-on connector was evident in this electrical panel.

    When I found this condition I suspected, and then confirmed that the worker who tried this approach did not follow CPSC recommendations, used an inappropriate connector which has a record of fires, and further, had failed to find and repair any of the splices in junction boxes in the building. Work like this is done by someone who has heard vaguely about "copper pigtailing" but has not become well informed on the topic. In my opinion, an improper or partial "repair" can in such cases actually increase the risk of overheating and fire.
  • Photograph of overheated multistrand aluminum wire on a 240V circuit.
    Overheated, burned multi-strand aluminum wire in this electric panel confirms that even contemporary practice of using multi-strand aluminum wiring in buildings, typically for single-use circuits like air conditioning, electric ranges, or clothes dryers, is still vulnerable to burnouts.


Also see COPPER-CLAD ALUMINUM WIRE (safe in homes) where we distinguish among copper-clad aluminum wire, plated copper wire, and CU/AL or COLAR devices.


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