Insulation of electric cables

NEW MINERAL FILLERS FOR COMPOUNDS USED IN THE INSULATION OF ELECTRIC CABLES... 

ORIGIN/INDUSTRY SOURCES/USES oil additive electroplating industry fabric dyeing production of electric condensers insulation of electric cables and wires supports for storage batteries solvent immersion liquid in microscopy... 

BS5468 Cross-linked polyethylene insulation of electric cables. 

Uses Prod, of electric condensers in insulation of electric cables/wires additive to EP lubricants supports for storage batteries coating in foundry use solvent immersion liq. in microscopy... 

OIT has been proved to be a useful diagnostic tool in assessing the extent of degradation in the polymer insulation of electric cables. Sample preparation and test conditions are parameters recognized to influence OIT results obtained by DSC. However, quantitative results on the variability of OIT as a function of these parameters have not been presented systematically in the literature. 

XLPE and EPDM cables OIT measurements using DSC Assessing the extent of degradation in the polymer insulation of electric cables in nuclear power plants Mason and Reynolds 1997... 

Insulation Applications One of the earliest uses for polymeric materials was for the insulation of electrical cables for power lines, etc. due to their low conductivity. In addition, polymers are now being used as thermal insulation in buildings, automobiles, etc. A few polymers (e.g., polybenzimidazole) have such high thermal resistance that they are used as fabrics for clothing of firefighters who must deal with very intense heat such as that in fires in buildings and oil wells. 

Living organisms can attack synthetic polymers chemically or mechanically. The mechanical mode refers to the attack by certain rodents and insects (especially for plastic insulation of electrical cables placed underground). 

Specification for 600/1000V and 1900/3300 V armoured electric cables having thermosetting insulation Fire resisting characteristics of electric cables Performance requirements, sample and lest conditions - BS 5467/1997... 

For offshore locations where ignitible gas-air concentrations are neither continuously present nor present for long periods, API RP 14F also allows type MC cable with a continuous aluminum sheath and an outer impervious jacket (such as PVC) and armored cables satisfying ANSI/ Institute of Electrical and Electronic Engineers (IEEE) Standard No. 45. API RP 14F does not recommend IMC for offshore installations and cautions users that installations of MI cable require special precautions. The insulation of MI cable is hygroscopic (able to absorb moisture from the atmosphere). 

EPDM is used for the insulating material of electric cable in nuclear power plant. As the properties of EPDM depend on their compounding formula, there are many receipts for improving heat resistant properties, durability against oil, resistance to ozone, and so on. 

The recovery of electric cable is long established because of its valuable copper content. After this conductor material has been extracted, the residue consists of sheathing and insulation that may contain rubber and polyethylene as well as PVC. These other materials can be largely removed from grinding, by flotation, vibration, and filtration, but rubber is especially difficult to remove entirely, so that applications for material recycled from cables containing it are limited to areas such as car mats and carpet underlay. 

The electrical properties of polymers are of considerable importance in various applications—the insulation of electrical or telecommunication cables, electrical components, electrical appliances and accessories, printed circuits, radar and electronics. Semiconductors based on polymers should also be mentioned. It is also possible to use electrical properties for monitoring or tests without fracture on stmcture or properties such as sequence of polymerization, degradation, and transition temperatures. Let s discuss briefly some major electrical properties. 

Uses Immersion liq. in microscopic determination of refractive index of crystals solvent for fats, oils, DDT in prod, of insulation for electric cables/wires... 

Experimental studies have shown that irradiation and heating of polyvinyl chloride insulation found on electrical cables in many reactor containment will yield both hydrochloric acid (HCl), sulfiirous acid (H2SO3), and sulfuric acid (H2SO4). Some investigators believe that acids formed by the combination of radiolysis and pyrolysis of electrical cable insulation can be of dominant importance to the pH of solutions in the reactor containment. Others feel that acid formation by this process is over-emphasized because acids generated within the pol5mer are not able to escape to the atmosphere except when they are formed near the polymer surface. 

Polyethylene is the most widely produced polymer worldwide and everyone comes into contact with it daily. Right from the start, PE was seen as an addition to the world of materials, although initially, its value was established as insulation for electricity cables. Nowadays, the strength of polyethylene lies in its intrinsic properties, its broadly accepted usefulness, and its large application potential. 

Poly(vinyl chloride) is used extensively in the construction industry (pipes, vinyl siding, window and door frames), for the insulation on electric cables. In clothing (such as in Goth and Punk fashion), for medical devices, and the manufacture of ordinary garden hoses. 

When the insulation of electric underground cables is damaged, so-called stray currents may arise, i.e. electric currents that are conducted through nearby water or gas pipes. This may cause serious electrolytic corrosion of the installations concerned. 

On March 22, 1975, a major fire occurred at TVA s Browns Ferry nuclear plants near Decatur, Alabama. This event was a close call that very nearly led to core damage. In the process of looking for air leaks in an area containing trays of electrical cables that supplied power to the plants control room and safety systems, a technician set off the fire. He used a lighted candle to conduct the search, and the open flame ignited the insulation around the... 

Extrusion moulding (used for making pipes, threads of fabric and insulation for electrical cables). 

This filler is useful when flame resistant compounds, with low smoke emission characteristics are being produced. Because compounds loaded with alumina retain good insulation properties (from the electrical point of view) hydrated alumina has been used successfully in the production of electric cable insulation compounds where good flame retardance is required. 

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