This standard applies to round zinc-coated steel wires used in the construction and/or reinforcement of conductors for overhead power transmission purposes. It is intended to cover all wires used in constructions where the individual wire diameters, including coating, are in the range of 1.25 mm to 5.50 mm. Types of wire are designated STyz, where y represents the grade of steel and z represents the class of zinc coating. To reflect the needs of conductor users, the only combinations of steel grade and zinc coating covered by this standard are ST1A, ST2B, ST3D, ST4A, ST5E and ST6C. The properties specified are those before stranding.