Insulating cable

Each segment of the insulated wire and cable industry has its own set of standards, and cables are built to conform to specifications provided by a large variety of technical associations such as The Institute of Electrical Electronic Engineers (IEEE), The Insulated Cable Engineers Association, (ICEA), National Electrical Manufacturers Association (NEMA), Underwriters Laboratories (UL), Rural Electrification Administration of the U.S. Department of Agriculture (REA), Association of Edison Illumination Companies (AEIC), MiUtary Specifications of the Department of Defense (MIL), American Society for Testing and Materials (ASTM), National Electrical Code (NEC), etc. 

Explosion-proof enclosures are characterized by strong metal enclosures with special close-fitting access covers and breathers that contain an ignition to the inside of the enclosure. Field wiring in the hazardous environment is enclosed in a metal conduit of the mineral-insulated-cable type. All conduit and cable connections or cable terminations are threaded and explosion-proof. Conduit seals are put into the conduit or cable system at locations defined by the National Electric Code (Article 501) to prevent gas and vapor leakage and to prevent flames from passing from one part of the conduit system to the other. 

MI Cables (mineral insulated cables. Fig. 10-181) are the electric heat tracers of choice for high-temperature applications. High-temperature applications are generally considered to maintain temperatures above 250°F or exposure temperatures above 420°F where self-regulating heaters cannot be used. MI cable consists of one or two heating wires, magnesium oxide insulation (from whence it gets its... 

A) 1 For busbars and busbar connections of aluminium or copper 2 For busbars and busbar connections of aluminium or copper silver plated or equivalent 3 Terminals for external insulated cables 50 65 70 90 105 110... 

Until a few years ago paper insulated cables had a dominant position but not so with the advent of XLPE cables (a devclop-ineni of the 1960s). in view of their higher thermal rating and availability in all voltage ranges up to 400 kV and above. This situation is almost similar to SF, technology over vacuum (Chapter 19), While vacuum is prefened it has limitations in HT above 33 kV as have paper insulated cables, which are available up to. 33 kV and have limitations beyond this. Hence the use of XLPE cables for HV and EHV installations... 

Figure A16.1 Different constructions of paper-insulated cables...

Fig. 14-4 Circuit diagram for a low-resistance dc decoupling devices. (KE) insulated cable end sealing, (E) grounding installation, (1) resistance ( 10 mfl), (2) grounding side bar or short-circuit-resistant grounding switch.

Bus bars of a transformer substation must not be directly grounded. They must be connected with rails by at least two insulated cables. Metal sheathing of feeder and return current cables must only then be connected with the rails or bus bar if an increase in anodic corrosion on other buried installations is absolutely excluded. The insulation of all return cables must therefore be monitored regularly. 

Another major type of coating process is wire covering. The tremendous demand for insulated cables in the electrical industry means that large tonnages of plastic are used in this application. Basically a bare wire, which may be heated or have its surface primed, is drawn through a special die attached... 

Standard Test Procedure for Flame Coatings Applied to Insulated Cables in Trays, 1993. 

Electrical components sockets, connectors, switches, insulators, cable clamps... 

Cable core The portion of an insulated cable lying under the protective covering or coverings. 

---