Power cable (a type of electrical cable) is an assembly of two or more electrical conductors held together and typically covered with an overall sheath. The conductors may be of the same or different sizes, each with their own insulation and possibly a bare conductor. A hybrid cable may also include other conductors (such as fiber optics), AC mains conductors, low-voltage data signalling or control conductors, and radio frequency conductors (such as coaxial cable). The sheath may be of metal, plastic, ceramic, shielded, sunlight-resistant, waterproof, oil-resistant, fire-retardant, flat or round, and may also contain structural supports such as kevlar, aerial wire, or other high-strength materials.

Common types of general-purpose cables used by electricians are defined by national or international regulations or codes. In the USA the definition is contained in the National Electrical Code or other International standards and are generally defined according to the conductors and the materials used, shape, and intended usage for the sheath. The conductors may be copper, aluminum, stranded, solid, and of various diameters as determined by the required amperage of the application. As mentioned, they may be individually insulated or bare. There may also be one or more conductive sheaths for reducing radio-frequency penetration of the sheath.

For example, NEC Type UF (underground feeder) is a non-metallic, flame-retardant sheath containing conductors having moisture-resistant insulation suitable for direct burial in the earth or in concrete. Type AC is a "metal clad" cable assembly made by twisting an interlocking metal tab or other metallic sheath around the insulated conductors. A common name is BX, after an early genericized trademark of the General Electric company.

Electrical power cables should be distinguished from electrical conduit , which may also contain one or more conductors, but is not a factory assembly of conductors held together, but rather just a sheath. Conduit may also be rigid or flexible, metallic or non-metallic, and differentiation from cable may require some investigation of the contents within the sheath or how the conductors are terminated in junction boxes. By comparison, most conduits are arranged so that their contents may be "pulled" or removed from an opening in the conduit, whereas conductors in cables are fastened to each other (or sheathed) and must be removed together. Cable is often installed in conduit for additional protection from physical damage, adding yet another level of complication.

Flexible cables

Cables are somewhat flexible, and are packaged in rolls or coils. However, in applications requiring a cable to be moved repeatedly, a more flexible cable should be used, called an "electrical cord" or "flexible cord." Flexible cords contain finely stranded conductors, rather than solid, and have insulation and sheathes that are specially engineered to withstand the forces of repeated flexing. See "Power cord" and "Extension cable" for further description of flexible power cables. Other types of flexible cable include twisted pair, coaxial, shielded, and communication cable .

See also

• Electrical wiring