Mining Communication Cable Identification and Length Marking Overview

The wire of the communication cable structure for mining was annealed bare copper wire with copper wire diameter of 0.30, 0.42, 0.52, 0.60, 0.70, 0.80, 0.90 (mm). Insulation High Density Polyethylene or Polypropylene. Indicate the color of the insulated wire according to the full color standard. Insulated pairs twist two different colors of insulated wire into pairs at different pitches and use the specified chromatographic combination to identify the pair. The cable structure of the communication cable is based on one pair. Over 25 pairs of cables are grouped by unit, and each unit is wrapped around the unit band of the specified chromatogram to identify different units. 100% or more pairs of cables have a 1% reserve line pair but no more than 6 pairs. The gap in the core is filled with petroleum jelly.

The core wrap is wrapped with polyester film tape. Shielded copper wire shields or embossed (or non-embossed) metal strips, which are wrapped outside the cable glands of the communications cable. Sheathed blue low density polyethylene. Double jacketed communication cables are also available. Identification and length marking of mining communication cables The cable has permanent identification marks on the outer surface of the cable. The marking interval is not more than 1m. The marking content includes: wire diameter, number of wire pairs, cable type, manufacturer's name and manufacturing year, and length mark. Intervals of not more than 1 m are marked on the outer surface but are staggered with the above marks. The mining communication cable adopts full-chromatization insulation, and the aluminum-plastic integrated sheath (that is, the longitudinal shielding aluminum tape of the cable is bonded with the sheath to form a seal sheath) has the advantages of superior electrical performance and convenient construction.

Causes of fire caused by mining communication cables are mainly due to overload, short circuit, excessive contact resistance and external heat source. In the short circuit, local overheating and other fault conditions and external heat, the insulating material insulation resistance, loss of insulation, and even burning, and then cause fire. The main characteristics of mining cables in fires are that the fire temperature is generally in the range of 800°C to 1000°C. In the event of a fire, the wire and cable will quickly lose their insulation capacity, which in turn will cause secondary electrical accidents such as short circuits, resulting in greater losses; wire and cable There is a large overload capacity under the specified allowable ampacity; in the short-circuit state, the wire and cable will instantly cause the insulating material to melt, burn, and ignite the surrounding combustibles.

Analysis of fire resistance of mine cables Fire protection mechanism analysis Flame retardance mechanism Under the thermal effect of combustion reaction, the flame retardant in the condensed phase decomposes and absorbs heat, which slows down the temperature rise in the condensed phase and slows down the thermal decomposition rate of the material; When the agent is decomposed by heat, a chain reaction free radical blocking agent is released, which interrupts the branch of the flame and chain reaction and slows the gas phase reaction rate; the condensed phase thermally decomposes the solid phase product, and the formation of a coking layer or a foam layer strengthens these layers. The hard shell impedes the heat transfer effect; under the effect of heat, the flame retardant undergoes an endothermic phase change and physically prevents the temperature in the condensed phase from rising. Fire resistance mechanism Adding an additive to the insulating and sheathing material of the mining cable reduces the heat generated by the polymer, prevents the polymer from decomposing or promotes the insulation of the insulating and sheathing material to form a protective layer; a layer of mica glass ribbon is added at the core of the line After the inorganic insulating material is ignited by the fire in the insulating and sheathing layer, the mica fireproof belt wrapped around the conductor will continue to be energized to maintain normal operation for a certain period of time during ignition.