Bunch stranding is a conductor construction method in which individual wires are twisted together in the same direction without following a predetermined geometric pattern.
In wire and cable manufacturing, stranding combines multiple small wires into a larger conductor. Bunch stranding twists all strands in the same direction in a loose, random formation. Unlike concentric stranding, which arranges strands in precise layers, bunch stranding has no set pattern. This makes it simpler and more cost-effective to produce while maintaining conductivity and flexibility. The resulting conductor is generally round but not perfectly symmetrical, so it is less suitable for precision applications like high-frequency RF cables. Instead, bunch stranding is widely used in low- to medium-voltage systems where flexibility, durability, and ease of termination are prioritized.
Bunch-stranded conductors are typically manufactured in accordance with ASTM (American Society for Testing and Materials), IEC (International Electrotechnical Commission), and UL (Underwriters Laboratories) standards.
Stranding methods were developed as electrical systems expanded and needed more flexible conductors than solid wire. Bunch stranding became a practical solution for environments requiring pliability and manufacturing efficiency, particularly in control and signal cable applications.