ACSS/TW is used for overhead distribution and transmission lines. It is designed to operate continuously at elevated temperatures up to 250°C without loss of strength, it sags less under emergency electrical loadings than ACSR/TW, excellent self-damping properties, and its final sags are not affected by long-term creep of aluminum. ACSS/TW is available in equal area and equal diameter design. The equal area design allows equal ampacity in a smaller diameter conductor when compared with a standard ACSS conductor. The equal diameter design allows more ampacity in an equal diameter conductor when compared with a standard ACSS conductor. ACSS/TW also provides many design opportunities for new line construction: i.e., reduced tower cost, decreased sag, increased selfdamping properties, increased operating temperature and improved corrosion resistance.
ACSS/TW is a composite concentric-lay-stranded conductor. Steel strands form the central core of the conductor with two or more layers of trapezoidal aluminum 1350-0 wires stranded around it. The steel core carries most or all of the mechanical load of the conductor due to the "0" (fully annealed or soft) temper aluminum. Steel core wires are protected from corrosion by high strength steel core, aluminum clad steel core is also available.
• ASTM B 857 Shaped Wire Compact Concentric-Lay-Stranded Aluminum Conductors, Coated-Steel Supported (ACSS/TW).