ALUMINUM WIRING: Aluminum branch wiring, when used for general lighting circuits, can be hazardous because of its tendency to oxidize and its incompatibility with fittings designed for other metals used in the electrical system. Improper connections can cause electrical resistance, which may in turn cause overheating and fires. These single strand aluminum wires, used in many houses built between 1961 and 1978, are not necessarily dangerous however. As long as proper connections are used, and the connections are made without damaging the wire, aluminum wiring is considered safe.
The main factor in determining whether a system is safe is the type of outlets and switches to which the aluminum wire is connected and the workmanship of the installation. Outlets and switches which are designated CO/ALR are considered appropriate for use with aluminum wire. These markings are found at the top or bottom of fixture mounting tabs, located under the plastic wall plates. Where indications are such that this is not the case, a licensed electrician should be called in to make a further evaluation of the system and to make repairs or modifications to the aluminum wiring to insure future safety.
Warning signs of unsafe aluminum wiring include: unusually warm or warped outlet and switch cover plates, smoke or sparks coming from outlets or switches, strange odors in the area of outlets and switches, periodic flickering of lights, or untraceable problems with plug-in lights and appliances. If any of the above are ever encountered, a licensed electrician should be called in to further evaluate the problem and make repairs as needed. The use of anti-oxidant paste on all exposed portions of aluminum wiring is also recommended as a precaution.