Aluminum wire is only potentially dangerous at connections with outlet plugs and other devices because that is where it potentially comes in contact with copper or other metal conductors. First, you need to make sure that the outlet plugs and devices directly hooked up to aluminum wire are rated for aluminum wire (with a CO-ALR code on it). The old AL-CU code is outdated because it approved certain devices that passed muster BEFORE the problems with aluminum-copper wire connections were fully discovered. Anything with a AL-CU code on it should be replaced.

The main danger of aluminum-copper connections is that aluminum and copper expand and contract at different temperatures. With normal temperature fluctuations, gaps form between the wires, which caused sparking, which caused fires in rare circumstances. Another danger is that because copper and aluminum have different metalurgical properties, they oxidize when in contact with each other. The oxidation undermines the connection, and eventually causes shorts or arching.

As such, any connections between copper and aluminum wire must be made with special wire nuts: Ideal makes one that they have patented that are purple and relatively expensive. (About $1-$2 each, as opposed to a few cents each for regular wire nuts). They use different metal than ordinary wire nuts that is somewhere between the metalurgical properties of copper and aluminum soas to minimize expanding. They also have an anti-oxidant gunk in them to prevent oxidation.

So long as the connections are safe, aluminum wire is fine. However, because of the risk that someone along the line will not know about these risks when doing work (replacing a ceiling fan, replacing an outlet), it is a good idea to replace aluminum wire with copper wire when feasible. Sometimes, even qualified electricians make improper copper/aluminum connections because it is not a common problem. For that reason, I replaced most of my aluminum wire during a gut rehab, except where the run was impractical to get at. I minimized the number of outlets that had aluminum wire: from about fifty to only five or six, where the circuits come in the room from the breaker). Also, simply because it is too easy to overlook these risks and make bad connections, aluminum wire is no longer approved by most building codes for new construction/remodels, and some codes require you to remove it when you do gut rehabs that remove the walls and make the wiring accessible.

[This message has been edited by Lawrence (edited January 08, 2002).]

[This message has been edited by Joe Tedesco (edited April 09, 2003).]

[This message has been edited by Electrical Inspector (edited September 30, 2002).]

Bill

[This message has been edited by Joe Tedesco (edited April 09, 2003).]