Used for overhead distribution and transmission lines. Designed to operate continuously at elevated temperatures up to 250 ºC without loss of strength. It sags less under emergency electrical loadings than ACSR; it is self-damping if prestretched during installation, and the final sags are not affected by long term creep of aluminum. The advantages make ACSS especially useful in reconductoring applications requiring increased current with existing tensions and clearances, new line applications where structures can be economized because of reduced conductor sag, new line applications requiring high emergency loadings, and lines where aeolian vibration is a problem.
ACSS is a composite concentric-lay stranded conductor. Steel strands form the central core of the conductor with one or more layers of aluminum 1350-0 wire stranded around it. The steel core carries most or all of the mechanical load of the conductor due to the (fully annealed or soft) temper aluminum. Steel core wires are protected from corrosion by galvanizing, aluminizing, or mischmetal alloy coating. Corrosion protection should be selected to suit the environment to which the conductor will be exposed. High strength steel core is also available.
ACSS conductor meets or exceeds the following ASTM specifications:
• B500 Metallic Coated Stranded Steel Core for Use in Overhead Electrical Conductors.
• B502/B502M (optional) Standard Specification for Aluminum-Clad Steel Core Wire for Use in Overhead Electrical Aluminum Conductors
• B609 Aluminum 1350 Round Wire, Annealed and Intermediate Tempers, for Electrical Purposes.
• B802 Zinc-5% Aluminum-Mischmetal Alloy-Coated Steel Core Wire for Aluminum Conductors, Steel Reinforced (ACSR).
• B803 High-Strength Zinc-5% Aluminum-Mischmetal Alloy-Coated Steel Core Wire for Use in Overhead Electrical Conductors.
• B856 Concentric-Lay-Stranded Aluminum Conductors, Coated Steel Supported (ACSS).
• B958 Extra-High-Strength and Ultra-High-Strength Class A Zinc-5% Aluminum-Mischmetal Alloy-Coated Steel Core Wire for Use in Overhead Electrical Conductors.