Many homes built in the 1960s to the mid 1970s were built using aluminum wiring. According to the U.S. Consumer Product Safety Commission, expansion, micro-fretting and arcing of aluminum wiring has been responsible for fires and even some deaths. Expansion and other deterioration processes can cause the aluminum wiring to overheat at connections between the wire and the fixtures or at the aluminum wire splices. Aluminum wiring connections have been reported to overheat or fail without any warning or indication of a problem. For these reasons aluminum wiring at smaller circuits, such as your lights and outlets, are no longer allowed. Aluminum wiring is still permitted to be used for service entrance cables and in single purpose circuits such as for your air conditioning or range. This is due to single purpose circuits have fewer connections than branch circuits making them less likely to fail and start a fire. I have also been told that some insurance companies may not cover a fire caused by aluminum wiring when the wiring has not been properly repaired.
During a home inspection, aluminum wiring observed at smaller lighting or outlet circuits should be called out as needing to have a qualified electrical contractor review the house wiring further and make correction or repairs as needed. An electrical contractor can make repairs to the aluminum wiring that will reduce or eliminate the possibility of the wiring over heating or failing. The most affective and costly correction is to replace the aluminum wiring with copper, this requires re-wiring the house. One alternative method is to attach a piece of copper wire at the connection points. This type of repair is known as “pigtailing”. Pigtailing a copper wire to an aluminum wire requires a special connector and the repair should only be performed by a qualified electrical contract.
Acceptable “Pigtail” repair method Twist-on Connectors are not a recommended repair
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