AAC (All Aluminum Conductor) is an overhead conductor made by concentrically stranding multiple layers of 1350-H19 hard-drawn aluminum wires, without a steel core or other reinforcing materials. Compared with Aluminum Conductor Steel Reinforced (ACSR), AAC's core advantages lie in lightweight construction and electrical conductivity: aluminum offers high conductivity and low density, giving AAC lower unit weight and lower DC resistance at the same cross-section, while the absence of a steel core means no hysteresis loss and lower line energy consumption.
However, the cost of this structure is equally evident. Lacking the mechanical support provided by a steel core, AAC has significantly lower tensile strength than ACSR, resulting in poorer sag performance. A comparative study of a 132kV system in Malaysia showed that AAC exhibits noticeably greater sag than ACSR Batang at operating temperature, making it unsuitable for reconductoring or uprating scenarios where sag is constrained. On lines with strong winds or long spans, AAC's sag under maximum working tension may exceed regulatory limits, which is also why it is excluded from certain transmission applications.
In terms of standards and specifications, AAC follows ASTM B231 and similar norms, with common constructions including 7-strand, 19-strand, 37-strand, and 61-strand concentric stranding, using 1350-H19 wires. Its typical applications are concentrated in medium- and low-voltage distribution lines, short-span lines, and situations requiring high conductivity but subject to relatively light mechanical loads. In distribution networks in markets such as Australia, AAC and ACSR are used together, with the former handling light-load distribution and the latter serving segments requiring higher mechanical strength.
From a selection logic perspective, AAC and ACSR are not substitutes but rather divided by mechanical load and sag requirements. When spans are short, wind and ice loads are controllable, and the goal is conductive efficiency and line lightweighting, AAC is a reasonable choice. When longer spans must be crossed or greater mechanical tension must be withstood, the steel-core reinforced structure of ACSR remains the more reliable solution.