| A common and legitimate concern is
about aluminum wiring. Aluminum, like copper, is a good conductor of electricity. Most of
the high voltage lines in this country are made of aluminum reinforced with steel.
Aluminum wire is also commonly used for the wire that connects a house to the power
transformer at the street. Aluminum was not used for the branch-circuit wiring that runs
throughout the house until the 1960's. In the early 1960's a copper shortage drove up the
price of copper. When this happened, electricians turned to aluminum wire. The problem is
that they were using aluminum in conjunction with switches, wall outlets, and light
fixture that were designed for copper wire. Unfortunately aluminum does not behave the
same way copper does. When aluminum is exposed to air, a film of aluminum oxide forms on
the metal's surface. This oxide is an insulator, not a conductor of electricity. If the
wire is not firmly attached to an electrical receptacle in the first place, the aluminum
oxide can build up rapidly. While aluminum, like other metals, expands when it gets warm
and contracts when it cools, it expands and contracts more than copper. When electricity
flows through an aluminum wire, the wire resists the flow of electricity and gets warm. If
the wire is held in place with a screw made of a dissimilar metal, the screw forces the
wire to expand, loosening the screw. When the current stops, the wire contracts. Although
the movements are microscopic, the continual expansion and contraction can eventually work
the wire loose. Vibrations and temperature changes around the wire can also lead to loose
connections. When the wire is no longer making a sound connection, arching will occur.
This is how fires are started. There are specific devices and methods that are considered
to be acceptable for use with aluminum wiring. If you a considering purchasing a home with
aluminum wiring, have an Electrician inspect the integrity of each connection in the home.
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