strand
A group of wires, usually twisted or braided.
strand: individual wire or twisted bundle in a cable
In electrical work, a strand is a single thin wire, typically 0.25 to 1.0 mm in diameter, that serves as the basic building block of a larger conductor. Multiple strands are twisted or braided together to form a flexible cable or cord. This structure gives the cable its ability to bend repeatedly without breaking, unlike a solid wire of equivalent cross-section, which would crack under flexing.
The number and gauge of strands in a cable determine its overall cross-sectional area and its rated current capacity. A cable marked as 2.5 mm2, for example, might contain 48 strands of 0.25 mm diameter copper wire twisted together. The pitch of the twist, measured in millimetres per rotation, affects both the mechanical flexibility and the electrical properties of the finished cable. Tighter twists improve flexibility but can slightly increase resistance.
Materials and layering
Strands are almost always copper or aluminium, chosen for conductivity. Each individual strand is typically insulated with a thin lacquer or enamel layer, especially in motor windings, where strands may be enamelled wire wound into coils. In power cables and cords, all strands together are wrapped in an outer insulation of PVC, rubber, or silicone.
During manufacturing, strands are drawn through dies to their target diameter, then spooled and fed into stranding machines that twist them in concentric layers. A three-layer concentric conductor, for instance, might hold 1, 6, and 12 strands in its inner, middle, and outer rings. This geometric packing is deliberate: it balances flexibility with electrical efficiency and reduces voids that trap moisture or allow corrosion.
The term strand also appears in signal cables and data lines, where shielding consists of fine tinned copper strands woven or braided over the signal conductors. Here, the strand count and weave pattern determine the shield's coverage percentage and effectiveness against electromagnetic interference. Poor strand contact or broken strands in a shield can degrade shielding effectiveness by 10 to 20 percent.