Stranded wires are used in a variety of electrical and electronic applications ranging from durable goods in homes to automobile components under the dashboard to rugged military cable assemblies. Types of stranded wire can vary, but it is commonly found in cable assemblies, wire harnesses, and networking or used in circuit boards, electronic devices depending on the application.
What is a Stranded Wire?
A stranded wire is made of a quantity of thin (usually copper) strands that are twisted and bundled together and generally enclosed in a PVC material to form a multi-stranded conductor.
Stranded Wire Applications
Stranded wires are mainly used for indoor applications. The benefits of stranded over solid wire is that stranded wire is made to bend and twist; the flexible, malleable wires are a preferable solution for connecting electronic components in difficult or small spaces such as in electromechanical assemblies and circuit boards. The inherent maneuverability of stranded wiring makes it much less susceptible to metal fatigue or cracking than single or solid stranded wire conductors.
Stranded Wire Types
Though the multiple small strands of wire bundled together make a flexible single conductor for applications, stranded wires come in several designs. The bundled strands can be configured into a variety of geometric arrangements to meet specific design requirements for any device or application. A few common types of stranded wire arrangements that can be arranged to optimize the final product include:
Concentric Strand
A common wire arrangement, concentric stranded wire is a conductor that consists of a central wire or core encapsulated by one or more layers of helically laid wires. The conductors are arranged in concentric circles, with each layer after the initial one having six more wires than the preceding layer. Concentric stranded wire arrangements reduce the need for filler material. The wires can be bunched together tightly to maintain the wire’s shape and help improve conductivity.
Bunch Strand
Such stranded wire arrangements do not have a specific geometry. The strands are bunched or collected together in the same direction. The grouping of wires are twisted together tightly to make sure they remain uniformly packed. The popularity of bunched stranding relates to their durability and flexibility. The small gauge wires bunched together, either braided or compressed, offer very good resistance power. The high malleability makes them ideal for bending around tight corners and spaces necessary for speakers, headphone cables, appliances, automobiles and so forth.
Rope Strand
Rope stranding groups wires together into several small bundles. Each component strand is itself stranded and then arranged into concentric circles to form a rope-like cable. The roping increases flexibility. This allows for greater movement in applications that require frequent moving or run in multiple directions. Larger gauge wire can also be used with rope strands, which adds to the durability and functionality of the application.
Annular Conductor
In this geometric arrangement, stranded wires are centered on a circular central core that is not typically conductive. The central core is surrounded by braided sets of strands which may be insulated or not. An electrically insulated protective covering is wound around the braid, which is wrapped in outermost aluminum foil protective covering. This helps the stranded wire material retain their shape, but also is helpful in reducing the wire’s resistance.
Compact Conductor
A compact stranded conductor is often utilized where smaller diameter applications are required. The individual strands of a larger, round conductor are bundled in layers in the same direction. Once the bundle is arranged, they are compressed to remove all of the triangular airspaces between the strands. The result is a much smaller finished conductor with no airspaces yet with the same amount of conductor cross section.
Stranded wires come in various geometric shapes to meet the design specifications of wire and cable assemblies and circuitries. Choosing the most effective type of stranded wire conductor for projects and applications is important for the success of your product. In doing so, the correct type of stranded wire for your application will improve its efficiency and, more importantly, reduce the chance that the application will need servicing in the future.
