page_title: Aluminum building wiring
section_title: Materials
hierarchical_section_title: Aluminum building wiring / Materials
caption_attribution_description: English: Etching of Overhead Telephone and Telegraph Wires in Broadway, 1890. "Wires snapped on a regular basis as a result of over tension, wind, or ice weighing them down. The electrical wires carried a significant charge, but the other wires carried electricity as well. As wires snapped and lashed across streets, smashing against buildings, thrashing about, spraying sparks in all directions, blocks were rendered impassable until power to the downed lines could be cut."
context_page_description: Aluminum building wiring is a type of electrical wiring for residential construction or houses that uses aluminum electrical conductors. Aluminum provides a better conductivity to weight ratio than copper, and therefore is also used for wiring power grids, including overhead power transmission lines and local power distribution lines, as well as for power wiring of some airplanes. Utility companies have used aluminum wire for electrical transmission in power grids since around the late 1800s to the early 1900s. It has cost and weight advantages over copper wires. Aluminum wire in power transmission and distribution applications is still the preferred material today.
  In North American residential construction, aluminum wire was used for wiring entire houses for a short time from the 1960s to the mid-1970s during a period of high copper prices. Electrical devices at the time were not designed with the particular properties of the aluminum wire being used in mind, and there were some issues related to the properties of the wire itself, making the installations with aluminum wire much more susceptible to problems.
context_section_description: Aluminum wire has been used as an electrical conductor for a considerable period of time, particularly by electrical utilities related to power transmission lines in use shortly after the beginning of modern power distribution systems being constructed starting in the late 1880s.  Aluminum wire requires a larger wire gauge than copper wire to carry the same current, but is still less expensive than copper wire for a particular application.
  Aluminum alloys used for electrical conductors are only approximately 61% as conductive as copper of the same cross-section, but aluminum's density is 30.5% that of copper.  Accordingly, one pound of aluminum has the same current carrying capacity as two pounds of copper.  Since copper costs about three times as much as aluminum by weight (roughly USD $3/lb vs. USD $1/lb as of 2017), aluminum wires are one-sixth the cost of copper wire of the same conductivity.  The lower weight of aluminum wires in particular makes these electrical conductors well suited for use in power distribution systems by electrical utilities, as supporting towers or structures only need to support half the weight of wires to carry the same current.
  In the early 1960s when there was a housing construction boom in North America and the price of copper spiked, aluminum building wire was manufactured using utility grade AA-1350 aluminum alloy in sizes small enough to be used for lower load branch circuits in homes.  In the late 1960s problems and failures related to branch circuit connections for building wire made with the utility grade AA-1350 alloy aluminum began to surface, resulting in a re-evaluation of the use of that alloy for building wire and an identification of the need for newer alloys to produce aluminum building wire. The first 8000 series electric conductor alloy, still widely used in some applications, was developed and patented in 1972 by Aluminum Company of America (Alcoa). This alloy, along with AA-8030 (patented by Olin in 1973) and AA-8176 (patented by Southwire in 1975 and 1980) perform mechanically like copper.
  Unlike the older AA-1350 alloy previously used, these AA-8000 series alloys also retain their tensile strength after the standard current cycle test or the current-cycle submersion test (CCST), as described in ANSI C119.4:2004. Depending on the annealing grade, AA-8176 may elongate up to 30% with less springback effect and possesses a higher yield strength (19.8 ksi or 137 MPa, for a cold-worked AA-8076 wire).
  A home with aluminum wiring installed prior to the mid-1970s (as the stock of pre-1972 aluminum wire was permitted to be used up) likely has wire made with the older AA-1350 alloy that was developed for power transmission. The AA-1350 aluminum alloy was more prone to problems related to branch circuit wiring in homes due to mechanical properties that made it more susceptible to failures resulting from the electrical devices being used at that time combined with poor workmanship.
  The 1977 Beverly Hills Supper Club fire was a notable incident triggered by poorly-installed aluminum wiring.
caption: New York City utility lines in 1890.
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