by Lou Perron
If you own a house with aluminum wiring, or are looking to buy or sell one, you may have some questions about the safety of aluminum wiring. Aluminum wiring has been a fire hazard in homes built in the late 1960’s through mid 1970’s. During that time, aluminum wiring was used in the branch circuits running through the home, and that’s where there have been problems.
Aluminum was used instead of the standard copper during this period because the price of copper had skyrocketed due to a combination of high demand for the Vietnam War, labor strikes reducing production and strong economic growth worldwide. Single strand aluminum wiring was created as a cheaper alternative to copper.
The problem with aluminum wiring is not so much with the wire itself, but with the connections. The wire running in the wall is not a problem. When electricity runs through wires, it causes the wire to heat up and expand. Aluminum wire expands and contracts at a higher rate than copper so connections to copper wire or screws at the terminals loosen over time. In addition, aluminum oxides build up on the surface of the wire and the connections, and create a layer which acts as a resistor and builds up heat. So while a house wired in 1969 might have not shown any problem, over time the potential for problems increases, as connections loosen and aluminum oxide builds up.
I recently had some buyers who were purchasing a home built in the late 1960s which was wired with single strand aluminum wiring throughout the house. Not only was this a concern to them, but several insurance companies refused to insure the house unless it was rewired or certain repairs were made.
The first solution to the aluminum wiring issue that most people think of is rewiring with copper. However, rewiring an entire home is expensive, but there are other solutions that are more cost effective. The Consumer Product Safety Commission (CPSC) has tested a number of these solutions and has come up with a guide that has satisfied the insurance companies. These involve what is called “pig tailing,” which means that the aluminum wire is connected to a short piece of copper wire which is then attached to the device, like a receptacle. This pig tailing must be done using specific types of connectors, either COPALUM or AlumiConn. Both have a corrosion coating, the first connecting the aluminum and copper wires through a special crimp connection and the latter using an internal metal lug that separates the wires and is tightened with a torque screwdriver.
This work should be done by a licensed electrician. And the insurance company may require that the electrician signs a letter saying that the work complies with the CPSC standards. Publication 516 on Aluminum Wiring by the CPSC can be found at: https://www.cpsc.gov//PageFiles/118856/516.pdf