An electrical cable is a group of insulated wires that are encased in sheathing. It typically has one hot wire to carry current, one neutral wire and one grounding wire, if present. A cable is classified based on the type of insulation, number of individual wires and the size or gauge of each wire. These numbers are commonly written on the cable, such as 14-2 w/G which indicates that the cable has two insulated wires with a grounding wire of 14-gauge.
Different types of conductors are used for different applications. Some are bare copper while others may be tinned or plated with another metal, such as gold or silver to extend their life and improve corrosion resistance. The way the conductors are stranded or braided together also affects the cables performance. Stranded conductors are more flexible than solid or twisted conductors. Solid conductors are usually thinner and heavier than stranded conductors.
Whether a cable is made from solid or stranded conductors determines how much current it can handle and its resistance to heat. It also depends on how it is protected and what environment it will be subject to during its lifetime. Some examples of specialized cables include those used in steel mills or boiler rooms (high temperature), on mobile equipment or on submarines (mechanical abuse), near nuclear reactors (high radiation), or in mines and chemical plants (corrosion).
Aerial power lines are conductors suspended from electrical towers to transmit electric power over long distances. Underground power cables are the opposite, they are buried in conduits to transport electricity under the ground.
Cord is a coiled cable that provides a temporary AC power supply for devices like portable tools, machines or appliances. It is usually plugged into a power outlet or extension cord for use. Cord is usually rated for a maximum voltage and amperage load depending on its construction.
Coaxial or twin lead cable is a round jacketed electrical cable used for transmission of signals such as television, audio and radio. It consists of an inner core with a tubular insulating layer and a conducting shield of braided wires. The shield is designed to prevent interference by picking up electromagnetic energy from outside sources.
Metallic sheathed cables are commonly used to supply mains electricity or to supply large appliances. They consist of three plain stranded copper wires, one for the current, one neutral and one grounding wire that are insulated with cross-linked polyethylene, PVC bedding and black sheathing. The sheathing is often reinforced with strands of steel wire to give the cable greater tensile strength.
Most electrical cables are made of multiple strands of copper that are bonded or twisted to form an assembly that is thicker than a single wire and yet much more flexible than a solid wire. The wires can be tinned or plated with other metals to increase corrosion resistance, make soldering easier and offer between-strand lubrication. In addition to the stranding of wires in an electrical cable, it may be bonded with a plastic or foil layer for additional protection.