Without getting overly technical, I would like to talk about Aluminum Wiring—the solid conductor stuff that was widely used from 1965 to 1975. As the prices of copper sky-rocketed in the 1960’s and 1970’s, aluminum wiring was widely used in residential construction for 15 and 20 amp branch circuits. As early as the 1970’s there was already evidence that there were problems related to the wiring being brittle, so the alloy was modified to be less brittle. Aluminum wire expands and contracts a lot more than copper. At the wiring connections, as the wire expanded and contracted, little gaps would start to develop which would lead to arcing. Unless you want to weld something—arcing is almost always bad juju.
This first picture is of a beautifully wired 1967 vintage electrical panel. “Technically” the only defect is the improper terminations of the newer “copper” circuits (neutrals and grounds terminated together). All of the aluminum wiring looks fine.
One of the main issues with the aluminum wire is that it is very soft—so soft that any nick could in effect reduce the wire size at the nick. Such a nick would then act like a fuse leading to: arcing.
Another serious problem with aluminum wiring occurs with remodeling. The remodeler decides to use copper wire and mixes the two types together. Now we have dissimilar metals complicating the issue leading to more: arcing. This next picture shows the combination of copper and aluminum wires in a junction box at the red wire nut. At the bottom of the junction box one of the wire nuts has completely melted away.
This next picture is of splices of aluminum wire outside of a junction box in an attic with obvious melting. In both of these cases the wire nut are not rated for use with aluminum wiring. The splices were the result of the wires melting off previously and then not being long enough to reach through the box when repairs were made so they were spliced “outside” the box and then more wires run into the box to go to the light fixture. Again dissimilar metals lead to more overheating and now the connections need repairs again.
These are just a few of the more serious issues that are associated with aluminum wire and they all can lead to serious fire safety concerns. Almost every aluminum wired house that I have ever inspected has had some arcing related conditions that could have resulted in loss of property or life. Aluminum wiring is perhaps my least favorite issue to find in a home—-and often results in my buyer walking away from the deal. When I have a house that was built between 1965 and 1975, checking for aluminum wiring is often the first thing I do—before getting too involved with the rest of the inspection.
While, there is some controversy over what to recommend and do about houses with aluminum wiring, the end result is going to be expensive. There are specific repairs accepted by the Consumer Product Safety Commission, involving installation of Copalum Connectors , that are considered by some to be an acceptable solution. There are very few contractors certified to make these connections (and are only recommended on the “second-generation” type wire). My concern with this approach is this: is “every” “single” connection going to be located and be properly repaired? Will there be even one junction box that will be missed—thus negating the entire repair?
It is my opinion that the “best” protocol is to rewire the home (especially those pre-1970 houses). If that is not an option then have the Copalum Connectors installed and add AFCI type circuit breakers to the circuits. These types of breakers are designed to pick up the kinds of arcing conditions associated with aluminum wiring.
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