A braid is a fibrous or metallic group of filaments woven into a cylindrical covering that protects or shields one or more wires.
In cable construction, a braid enhances durability, shielding, or reinforcement depending on its material. Braids are woven in a uniform cylindrical pattern around conductors and may be made from fibers such as cotton, glass, or nylon, or from metals like copper and tinned copper. Fibrous braids often include treatments to resist moisture and fraying, while metallic braids provide electromagnetic interference (EMI) and radio frequency interference (RFI) shielding. Metallic braids form a conductive layer that grounds unwanted signals, ensuring stable transmission in AV, communication, and industrial systems. Fibrous braids increase abrasion resistance and flexibility, especially in cables exposed to frequent handling or movement.
Braid materials and performance are evaluated under standards from UL (Underwriters Laboratories), ASTM (American Society for Testing and Materials), and IEC (International Electrotechnical Commission). Shielding effectiveness is also referenced by IEEE (Institute of Electrical and Electronics Engineers) and TIA (Telecommunications Industry Association).
Since the early 20th century, braided coverings have been used in wiring to provide protection and flexibility. Cotton braids were first used as conductor wraps, later joined by metallic braids to meet shielding demands in telecommunications and broadcasting. The introduction of synthetic fibers such as nylon and glass expanded braid applications, adding greater resistance and strength for modern industrial and commercial cabling.