Cable
A cable is one or more strands bound together. Electrical cables may contain one or more metal conductors, which may be individually insulated or covered. An optical cable contains one or more optical fibers in a protective jacket that supports the fibers. Mechanical cables such as wire rope may contain a large number of metal or fiber strands.
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History
Ropes made of multiple strands of natural fibers such as hemp, sisal, manila, and cotton have been used for millenia for hoisting, hauling. By the 19th century, deepening of mines and construction of large ships increased demand for stronger cables. Invention of improved steelmaking techniques made high quality steel available at lower cost, and so wire ropes became common in mining and other industrial applications. By the middle of the 19th century, manfacture of large submarine telegraph cables was done using machiners similar to that used for manufacture of mechanical cables.
In the 19th century and early 20th century, electrical cable was often insulated using cloth, rubber and paper. Plastic materials are generally used today, except for high reliability power cables.
Electrical cables
Electrical cables may be made flexible by stranding the wires. The technical issue is to reduce the skin effect voltage drop while using with alternating currents.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 improved striping of rubber, or for low friction of moving conductors, but it could be silver, gold and another materials and of course the wire can be bare - with no coating material) on the individual wires. 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.
Fire protection
In building construction, electrical cable jacket material is 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. The plastic covering on some metal clad cables may be stripped off at installation 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.
To provide fire protection to a cable, there are two methods:
a) Insulation material is deliberately added up with fire retardant materials
b) The copper conductor itself is covered with mineral insulations( MICC cables)
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.
Electrical cable types
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)
- Twisting cable
Construction
Based on construction and cable properties it can be sorted into the following:
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
Application
- Wire rope (wire cable)
- Audiovisual cable
- Bicycle cable
- Communications cable
- Computer cable
- Mechanical cable
- Submersible cable
Cable manufacturers
The leading global producers of electrical wire and cable include (in no particular order): Clynder Cables, Cords Cable, Canare, Draka, General Cable, Belden, Nexans, 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.
Further reading
- R. M. Black, The History of Electric Wires and Cables, Peter Pergrinus, London 1983 ISBN 0 86341 001 4
See also
Wiktionary, the free dictionary.
- 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
- Category 5 cable
- Category 6 cable
- Category 7 cable
- Cross-linked polyethylene
- DOCSIS
- Electrical wiring
- Extension cable
- MF
- Polyvinyl chloride
- Portable cord
- Power cable
- Profibus
- Submarine communications cable
- Submarine power cable
- SY Control Cable
- Tensile structure
- 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
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