Aluminum Wire - ACM Wire

ACM Wire

The first 8000 series electric conductor alloy, still widely used, 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 AA-1350 series, these 8000 series alloys retain their tensile strength after the standard current cycle test or the Current Cycle Submersion Test (CCST); both tests are 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 for a coldworked AA-8076 wire).

Building wire in US jurisdictions now uses the new 8000 alloy of aluminum as specified by the National Electrical Code (NEC). Contractors are also using a larger gauge aluminum building wire for low voltage feeders where the savings over copper is significant due the lower weight. Aluminum building wire will have half the weight of copper even though the aluminum conductor must have 50% greater area than copper to carry the same current. The aluminum conductors used for building wire may be compacted in such a way that the overall diameter of the aluminum wire is approximately the same as copper.

This alloy, when used with CO/ALR devices and aluminum-rated twist-on connectors, can be just as safe as copper wiring. However it is extremely rare in branch circuit wiring, and most twist-on connectors in typical branch-circuit sizes, even those designed to connect copper to aluminum wiring, are not rated for aluminum to aluminum connections (an exception is the Marette 63 and Marette 65). A home with aluminum wiring installed prior to 1972 probably has the older 1350 series alloy that was designed for power transmission. Due to their undesirable mechanical properties, most 1350 alloys were not suitable for branch wiring.