Wire

Wire is a single conductive strand or a bundle of strands made from metal, designed to carry electricity or transmit mechanical load. Electrical wire typically uses conductive metals such as copper or aluminum and may be insulated to prevent short circuits. When multiple conductors share a common sheath, the assembly is called a cable rather than a single wire.

Common wire forms include solid wire, which is a single uninterrupted strand, and stranded wire, composed of multiple thin strands for flexibility. Copper is the predominant electrical conductor because of its high conductivity and ductility; aluminum is lighter and cheaper but has higher resistivity. Steel or alloy wires are used for reinforcement and mechanical applications, such as wire rope and guy wires. Wires may be coated or plated, and electrical wires are often insulated with plastics such as PVC or with enamel coatings for winding applications.

Manufacture typically involves drawing metal through successively smaller dies to achieve the desired diameter, followed by annealing to adjust softness. Electrical resistance is proportional to resistivity and length; ampacity, or current-carrying capacity, depends on cross-sectional area, insulation, temperature, and environment. Wire gauges are described by systems such as AWG in the United States or cross-sectional area in square millimeters elsewhere.

Primary uses include building electrical installations, automotive wiring, electronics assemblies, and telecommunications. In industry, wire is also employed in products like wire rope, springs, and fasteners. Safety and performance standards regulate conductor material, insulation, voltage rating, and allowable temperature rise.

Standards are provided by organizations such as IEC, ASTM, and UL, and color coding or marking aids identification of conductor type and rating. The term "wire" thus encompasses a range of products from thin enamel-coated windings to heavy-duty cables used in power transmission.