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 ElectricalMission
History Feeder and branch-circuit wiring systems were designed primarily for copper conductors. Aluminum wiring was evaluated and listed by Underwriter’s Laboratories for interior wiring applications in 1946; however, it was not used heavily until 1965. At that time, copper shortages and high prices made the installation of aluminum branch-circuit conductors a very attractive alternative. At the same time, steel screws became more common than brass screws on receptacles. The aluminum wire and the receptacle devices were both listed in accordance with the available product standards. As aluminum wire was installed more frequently, the industry discovered that changes were needed to improve the means of connecting and terminating smaller aluminum wire. Installation methods for utility grade aluminum conductors were also different, and workmanship was an important factor in making reliable connections. The National Electrical Code has permitted the use of aluminum wire since 1901, a mere four years after the first recognized national electrical code was published in 1897. This is remarkable considering that aluminum had only been commercially feasible in large quantities since 1889 with the combined improvements in refining alumina from bauxite (the Bayer process in 1889) and producing molten aluminum from alumina (Hall-Heroult process in 1886). By comparison, many sources indicate that copper has been used for thousands of years, and the modern electric system only began in the 1880s. The NEC has required aluminum alloy conductors for branch-circuit wiring (12–8 AWG) since 1981. The Code never explicitly prohibited aluminum building wire; however, there was a period in the early 1970s when UL withdrew the listing for aluminum building wire and revised the listing to require aluminum alloy conductors. During this process, there was no listed aluminum building wire available except remaining stock. Today’s “new technology” aluminum building wire is made of AA-8000 series aluminum alloy. These alloys were developed in the late 1960s and were listed and manufactured beginning in 1972. At about the same time, CO/ALR devices were required for aluminum wire branch circuits and listed by UL. These devices were developed to be used reliably with 10 and 12 AWG conductors and must have brass screws. Aluminum building wire today is at least as safe and reliable as copper building wire. Listed connectors are evaluated and manufactured specifically for aluminum connections. AA-8000 conductors now have over 30 years of field installation examples proving their reliability and have been recognized in the NEC for nearly 20 years. AA-8000 series aluminum alloy conductors provide a safe and reliable method of designing and installing electrical systems. They are available as single conductors, in cable assemblies such as MC cable and SE cable, and a variety of other configurations to meet the needs of different installations. Products and Applications In 2010, electrical market applications rose 13.1 percent, to 1.472 billion pounds. Shipments of ACSR, bare cable, and insulated wire and cable products totaled 631 million pounds, off 11 million pounds from the previous year. The North American electrical market was the fourth largest for aluminum, accounting for 7.3 percent of all aluminum shipments during the year. Members Residential |
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