Applications Used as bare ovehead transmission cable. Self-damping conductor limits aeolian vibration to a safe level regardless of conductor tension or span length. Other conditions - such as the number and cost of angle and deadend towers - being compatible, higher conductor tensions with associated shorter towers or longer spans are practicable. Specifications SURAL bare ACSR/SD meets or exceeds the following ASTM specifications: B-230 Aluminum Wire, 1350?H19 for Electrical Purposes B-701 Concentric-Lay-Stranded Self-Damping Aluminum Conductors, Steel Reinforced (ACSR/SD)The tables include a range of sizes and strandings. Other designs can be furnished to meet special and unusual requirements but it would be impractical to list all the possible stranding combinations and sizes. Construction ACSR/SD is a concentrically stranded conductor composed of two layers of trapezoidal shaped wires or two layers of trapezoidal shaped wires and one layer of round wires of hard-drawn 1350 aluminum alloy stranded with a high-strength coated steel core. The core may be a single wire or stranded depending on the size. Because of the numerous stranding combinations of aluminum and steel wires that may be used. it is possible to vary the proportions of aluminum and steel so as to obtain the relation between current carrying capacity and mechanical strength best suited for each application. For instance a conductor having a small proportion of steel may be most economical for a wood pole line to transmit a large block of power whereas a conductor with a very large proportion of steel would be required for a long span crossing over a navigable body of water. Between these two extremes are the conductors with normal proportions of aluminum and steel generally used for the more conventional transmission and distribution lines.