Aluminum Wire

A large number of homes constructed between 1965 and 1975 were completed with aluminum distribution wire.  While aluminum wire is still in common use for service wires (from the utility to you), it has turned out to be a poor product for interior distribution wiring (from the panel to interior fixtures). 

History

The Problem

All metal rusts.  It even rusts inside your climate controlled house.  It just takes longer than wires exposed at the exterior.  Copper Oxide (copper rust) is a conductor.  In other words the wire continues to operate as usual.  Aluminum Oxide (Aluminum rust) is a resistor.  As rust builds up on a fixture connection there is more resistance.  Resistance equals heat and heat can equal fire. 

The Solution

Rewiring is generally not required.  It can be done, but it is the most expensive option.  At a minimum all fixtures wired to aluminum wire must be approved for use with aluminum.  They are usually stamped with a designation of "Cu/AL". 

A better solution is two procedures known as "pig tailing" or "crimping".  Both procedures involve adding a short section of copper to the end of the aluminum wire with an approved, non-removable device so that you can then connect the copper wire to the fixture and remove the resistance risk.