According to the U.S. Consumer Product Safety Commission, aluminum wiring used in some homes built from the mid-60’s to the early-70’s, is a potential fire hazard.
CPSC research shows that homes wired with aluminum wire manufactured before 1972 are 55 times more likely to have one or more connections reach Fire Hazard Conditions than are homes wired with copper.
According to CPSC research, fires and even deaths have been reported to have been caused by this hazard.
Aluminum wiring is still permitted and used for certain applications, including residential service entrance wiring and single-purpose higher amperage circuits such as 240V air conditioning or electric range circuits.
The fire risk from single purpose circuits is much less than for branch circuits.