• An 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.

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  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

• 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.

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  Where wiring is visible in the attic or basement, examine the insulation for markings that indicate the use of aluminum, such as "KAISER," "ALCAN," "ALUMINUM," or "AL/2." If you see #14, or 14-gauge wiring, that particular wire is unlikely to be aluminum, unless someone did something quite unusual for residential construction. Here's a closeup of some aluminum wiring insulation jacketing which shows the "12/2" indicating it's No. 12 gauge wire.

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  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.

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

• 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 Wire Connector Availability discusses how to get the proper aluminum wire connectors

• 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],

• Scotchlok 3M Repair Method [- Superceded by new alternate repair as of June 2007 -] was previously recommended, prior to successful testing of the AlumiConn (see AlumiConn and COPALUM methods introduced at How to Reduce the Risk of Aluminum Wiring). We no longer recommend this repair method, but in because it may be encountered in the field, a summary description of this method is at PIGTAILING USING "Scotchlok" TWIST-ON CONNECTORS and a detailed description of this method is atAluminum Wire alternative repair: Special Aluminum Wire Repair Method using a Specific Twist-on Connector and Other Details.

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  The 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.

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  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.

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