Cable

From Wikipedia, the free encyclopedia

6" or 15cm outside diameter, oil-cooled cables, traversing the Grand Coulee Dam throughout. These cables are connected to powerful pumps that pump the oil through them while in operation. Safety switches turn off the oil flow in the event of a leak, in order to limit the effects of a hydrocarbon fire.

Fire test in Sweden, showing rapid fire spread through burning of cable jackets from one cable tray to another.

500MCM 1C Power Cable Marking

A cable is one or more wires or optical fibers bound together, typically in a common protective jacket or sheath. The individual wires or fibers inside the jacket may be covered or insulated. Combination cables may contain both electrical wires and optical fibers. Electrical wire is usually copper because of its excellent conductivity, but aluminium is sometimes used because it is lighter or costs less.

Construction

Electrical cables may be made flexible by stranding the wires. In this process, smaller individual wires are twisted or braided together to produce larger wires that are more flexible than solid wires of similar size. Bunching small wires before concentric stranding adds the most flexibility. A thin coat of a specific material (usually tin-which improves the solderability of the bunch-, but it could be silver, gold and another materials and of course the wire can be unplated - with no coating material) on the individual wires provides lubrication for longest life. Tight lays during stranding makes the cable extensible (CBA - as in telephone handset cords).

Bundling the conductors and eliminating multi-layers ensures a uniform bend radius across each conductor. Pulling and compressing forces balance one another around the high-tensile center cord that provides the necessary inner stability. As a result the cable core remains stable even under maximum bending stress.

Cables can be securely fastened and organized, such as using cable trees with the aid of cable ties or cable lacing. Continuous-flex or flexible cables used in moving applications within cable carriers can be secured using strain relief devices or cable ties. Copper corrodes easily and so should be layered with Lacquer.

History

In the 19th century and early 20th century, cable was often insulated using cloth, rubber and even paper. Plastic materials are generally used today, except for high reliability power cables. There are four types of plastic insulation used in telecommunications cables today: solid, cellular, foam skin and skin-foam-skin.

The leading global producers of wire and cable include (in no particular order): Canare, Draka, General Cable, Belden, Nexans, India, igus, Sumitomo Electric Industries, Furukawa Electric, Hitachi Cable, Southwire, Marmon Group, LS Cable, Leoni, Fujikura, Tyco, Prysmian, Lapp, Wonderful Hi-Tech, Walsin Lihwa and Wilms Group, and Jainson Cables - India.

Fire protection

Cables as a fire hazard

In construction, sometimes the cable jacketing is seen as a potential source of fuel for a fire. To limit the spread of fire along cable jacketing, one may use cable coating materials or one may use cables with jacketing that is inherently fire retardant. Teck cable or metal clad cables, may have exterior organic jacketing, which is often stripped off by electricians in order to reduce the fuel source for accidental fires. In Europe in particular, it is often customary to place inorganic wraps and boxes around cables in order to safeguard the adjacent areas from the potential fire threat associated with unprotected cable jacketing.

Interference protection

In applications powering sensitive electronics, keeping unwanted EMI/RFI from entering circuits is important. This can be accomplished passively with shielding along the length of the cable or by running the cable in an enclosure separate from any other wires which may induct noise. It can also be actively achieved by use of a choke designed to restrict the cables' ability to conduct certain frequencies.

Types of cable

Cables can be sorted into several categories and types. Generally it can by sorted into two main groups, structural and informatic.

Application

• Wire rope (wire cable)
• Audiovisual cable
• Bicycle cable
• Communications cable
• Computer cable
• Mechanical cable
• Submersible cable

Cable type

Basic cable types are as follows:

Basic

• Coaxial cable
• Multicore cable (consist of more than one wire and is covered by cable jacket)
• Optical fiber cable
• Ribbon cable
• Single cable (from time to time this name is used for wire)

Construction

Based on construction and cable properties it can be sorted into the following:

• Mineral-insulated copper-clad cable
• Twinax cable
• Twisted pair cable
• Shielded cable
• Flexible cables

Special

• Arresting cable
• Bowden cable
• Heliax cable
• Direct-buried cable
• Heavy-lift cable
• Elevator cable

Market Information

• Integer Research Ltd
• International Cable Makers Federation
• Wire Association International

See also

Look up cable in
Wiktionary, the free dictionary.

A 250V-16A electrical wire on a reel

• Communications cable
• Mineral-insulated copper-clad cable
• Cable harness
• Cable lacing
• Cable length
• Cable tray
• Circuit integrity
• Cable management
• Cable modem
• Cable salad
• Cable television
• DOCSIS
• Extension cable
• MF
• Portable cord
• ROHS
• Submarine communications cable
• Submarine power cable
• Tensile structure
• Wire rope (steel cable)
• International Cablemakers Federation

External links

• Malaysia Cable Manufacturers Association
• National Electrical Manufacturers Association
• The European Confederation of National Associations of Manufacturers of Insulated Wire and Cable