Aluminum wire is solid, silver-colored aluminum, not just coated copper. It was popular only for a brief window of time in the early 70s. During the Vietnam war, copper was less available and a big scare hit that copper supplies would not be sufficient to meet electrical needs. The aluminum industry swept in with a big promotional campaign, and convinced people to use it until the safety problems with aluminum wire became well known. It was banned from new construction shortly thereafter.
There is copper-coated aluminum wire, which can be treated as copper wire, but there is no aluminum-coated copper wire so far as I know.
[This message has been edited by Lawrence (edited January 25, 2001).]
"Copper-Clad Aluminum Conductors.
Conductors drawn from a copper-clad aluminum rod with the copper metallurgically bonded to an aluminum core.
The copper forms a minimum of 10 percent of the cross-sectional area of a solid conductor or each strand of a stranded conductor.
Snap switches rated 20 amperes or less directly connected to aluminum conductors shall be listed and marked CO/ALR.
Receptacles rated 20 amperes or less and designed for the direct connection of aluminum conductors shall be marked CO/ALR."
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