Aluminum wiring was used in homes and mobile homes from the mid-1960s to the mid-1970s. Although solid (single strand) aluminum wiring was approved for household 15- and 20-amp circuits since the 1940s, it was not used much until the price of copper skyrocketed in the mid-1960s. The formula for the aluminum alloy used was changed in 1972, which made the wiring somewhat safer, and specially designed breakers and connectors were produced, but this wiring was totally phased out by the mid-1970s.

    The main problem was a loosening of the wire connections due to the high rate of thermal expansion and contraction compared to copper, and homes with aluminum wiring were much more likely to have electrical fires. But multi-strand aluminum wiring is still extensively used in homes for higher-amperage circuits and code approved. So aluminum wiring has not gone away, only single strand #12 and #10 AWG.

    Also, see our blog posts I heard that aluminum wiring is bad. How do you check for aluminum wiring? and Do any pre-1960 houses have aluminum wiring?

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Here’s links to a collection of our other blog posts about ELECTRICAL WIRING:

• Which house appliances need a dedicated electrical circuit?

• Can a short circuit cause a high electric bill?

• What is the maximum spacing requirement for securing NM-cable (nonmetallic-sheathed cable)?

• Is it alright to just put wire nuts on the end of unused or abandoned NM-cable or wiring?

• What causes copper wires to turn green or black in an electric panel?  

• What are typical aluminum service entrance wire/cable sizes for the electrical service to a house?

• Why is it unsafe to bond neutral and ground wiring at subpanels?

• Should I get a lightning rod system to protect my house?

• Why is a strain relief clamp necessary for the cord connection to some electric appliances?  

• Does a wire nut connection need to be wrapped with electrical tape?

• What is the minimum clearance of overhead electric service drop wires above a house roof?

• What are the requirements for NM-cables entering an electric panel box? 

• What is the color code for NM cable (Romex®) sheathing?

• Why are old electrical components not always "grandfathered" as acceptable by home inspectors?

• How can I find out the size of the electric service to a house?

• Can old electrical wiring go bad inside a wall? 

• What is an open electrical splice?

• What are the most common electrical defects found in a home inspection? 

• What is the life expectancy of electrical wiring in a house? 

• What is an "open junction box"? 

• How dangerous is old electrical wiring? 

• What is a ground wire?   

• What is "knob and tube" wiring?  

• What is the code requirement for receptacle outlets in a closet?

   Visit our ELECTRICAL page for other related blog posts on this subject, or go to the INDEX for a complete listing of all our articles.