Coverings are protective layers applied over wires or cables, typically made from textiles, rubber, plastics, or other durable materials. They protect inner components from mechanical damage, environmental stress, and can assist with identification or organization of circuits.
In cable construction, coverings form the outermost layer that shields insulated conductors and internal assemblies from abrasion, moisture, chemicals, and physical impact. Also referred to as jackets or braids, these coverings are vital for extending cable service life and maintaining stable performance in commercial and industrial environments.
Different types of coverings are used based on application needs. Textile braids provide flexibility and abrasion resistance, while molded jackets made from materials like rubber, PVC, polyethylene, or thermoset compounds offer enhanced resistance to heat, UV exposure, and chemicals. In complex wiring systems, coverings may also be color-coded or printed for easier circuit identification, voltage classification, or phase marking, key for organized, large-scale installations in AV, data, and control systems.
Beyond mechanical protection, coverings contribute to electrical safety by maintaining insulation integrity and shielding conductors from interference. In shielded cables, the covering also secures and protects underlying metallic shields that block electromagnetic (EMI) and radio frequency interference (RFI), preserving signal clarity and system reliability.
Cable coverings are regulated by standards set by UL (Underwriters Laboratories), CSA (Canadian Standards Association), and IEEE (Institute of Electrical and Electronics Engineers). These organizations define testing procedures for flame resistance, mechanical strength, and environmental endurance to ensure safe and consistent performance in industrial systems.
The use of coverings in cabling dates back to early telegraph systems, where cloth and tar-coated materials provided basic protection against wear and environmental damage. The development of synthetic polymers in the 20th century revolutionized cable protection, introducing materials that improved flexibility, insulation strength, and fire resistance. Modern coverings now combine advanced chemical formulations and layered constructions to meet the rigorous demands of today’s industrial, data, and AV networks.