Since it is believed to be the cause of many house fires, the everyday usage of aluminum wiring installed during the 1970s is no longer allowed in most cities. If installed correctly, aluminum wire can be as safe as copper wire. When installed incorrectly, aluminum wire can become very problematic.
All electrical wiring expands and contracts at different rates. When aluminum wire expands and contracts, it does so at a greater rate than copper and this is where the problem lies with aluminum wiring. After several of these expanding and contracting cycles, the metal tends to lose its ability to remain tight. This leads to aluminum wiring becoming disconnected from the receptacles and creates arching, which leads to house fires.
Aluminum (when in contact with other metals such as copper) tends to oxidize and cause serious problems. The oxidized aluminum becomes hotter while attempting to conduct the same amount of electricity, causing more oxidation. This cycle will eventually cause the wires to become extremely hot and possibly cause a fire.
Suppose a house is discovered to have aluminum wiring during the inspection process. If this is the case, it is recommended to hire a licensed electrician to check for any potential problems.
There are a few options for correction. The Consumer Product Safety Commission (CPSC) only recommends the three following methods for correction of aluminum wiring:
Rewire the home with copper wire. Most of the time, this is expensive and impractical.
Using COPALUM connectors to pigtail the aluminum wiring to copper. (Pigtailing involves connecting a short piece of insulated copper wire between the aluminum wire and the switch or receptacle connecting terminals.) This method would need to be performed by a licensed electrician who is also a certified COPALUM installer.
Using AlumiConn™ lug connectors to attach copper wiring to the existing aluminum wiring. This should also be done by a licensed electrician who is familiar with these techniques since these require very specific installation instructions and proper installation is critical for these devices.
Any other methods of “fixing” aluminum wiring is not CPSC approved. Aluminum wiring can be a fire hazard due to the inherent qualities of the metal. Identification and correction will decrease the chances of an electrical fire.
For additional information on how to properly repair aluminum wiring, please see: https://inspectapedia.com/aluminum/Aluminum_Wiring_Repair_Methods.php