The best conductors are made of non-magnetic metals such as copper and aluminum. (Actually, the best metal conductor of all is silver, but of course, silver is much too expensive to use when it comes to wiring a structure as large as a house.) Here are some things to know about aluminum vs copper conductors from the Santa Fe electricians at Gorman Lightning and Electric.
One of the few metals that are not silvery, or gray, copper is known for its bright reddish-orange color. It’s not only an excellent conductor of electricity but is very malleable and ductile. When pure copper is annealed, or subjected to a special heat treatment, it conducts 100 percent of the electrons that flow through it. Copper’s ductility allows it to be pulled into wire, and its malleability allows it to be easily beaten into thin sheets. It is also very strong, conducts heat well, and does not expand as much as aluminum when exposed to heat. Copper is mined from pits in many places throughout the world, including the United States and Chile.
Aluminum conducts electricity 61 percent as well as copper but weighs 1/3 as much. Because of this, aluminum conductors are less expensive than conductors made of copper. Most aluminum wires made to conduct electricity are made of aluminum alloys. The aluminum AA-1350 series is 99.5 percent aluminum with 5 percent of iron, copper, silicon, and other metals. It was very popular during the 1960s and 1970s for wiring homes because it was so inexpensive. Because of problems with the AA-1350 wire, aluminum wiring is no longer used.
Another problem with aluminum was that it was very hard to mine until the late 19th century, while copper has been mined for thousands of years. Even though it is the most common metal in the crust of the earth, aluminum was so hard to find that it was more expensive than gold for a time. The difference is in the reactivity of aluminum vs. copper. Aluminum is a very reactive metal in its pure state. Copper is not so reactive and can be found naturally. Aluminum is usually retrieved from an ore called bauxite after a fairly involved process.
The problems with wiring houses with aluminum are not really the fault of the metal. Aluminum wiring was installed so extensively and so quickly that the workmanship was substandard. The fact that aluminum expands more than copper when it is heated made for loose connections, which created fire hazards. The connections could also be made of copper or some other metal and led to corrosion when they came into contact with aluminum wire.
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