This type of construction has the following additional advantages:Cables are lighter in weightEasy to installCan be installed on poles, on walls etc.Easy to make terminations and branch off joints on live wire as well Protection against power theft.AERIAL BUNCH CABLES are part of power distribution cables, developed earlier in Europe at Sweden and Norway to be installed on overhead poles where underground excavation was not easy because of hard rocky soil. In due course these cables became popular in various parts of Europe and USAas well.Further, installation was easy. Teeing off was not cumbersome. Maintenance was also not tiresome. The insulated power cores in these cases can not be tampered with. Construction of the cable is simple, though, manufacturing needs very special care for proper & longer performance during operation. Paramount Cables after analysing and studying the significant critical features of this particular cable have taken special measures to manufacture this item to give reliable service for a longer period of time. Following points need to be noted.ConductorSpecial care has been taken to form conductor in the factory. Lay length is chosen based on IS:398. Residual stress which remains in the conductor after coming out of die-head is removed by compacting the conductor, reducing the electrical stress as well. The compacted conductor allows uniformity of extruded insulation. yAs for messenger conductor, monitoring is done from the wire rod stage, to solution treatment to ageing after wire drawing. During stranding same precaution is taken to remove the internal stress of the conductor. This is advantageous for laying the cable uniformly.InsulationHigh quality contamination and moisture free grafted polymer is selected after in house testing to ensure reliable service. XLPE (Sioplas) insulation while being extruded over the conductor, is made stress free by special manufacturing technique. Curing is done under controlled conditions to obtain consistent result giving dimensional stability.Twisting/LayingBasic factor is the peculiar form of twisting the insulated conductor around the messenger conductor. While twisting the phase conductors around the messenger conductor, messenger conductor is to remain in the centre position supporting the phase conductors. Special technique has thus been adopted by Paramount Cables to ensure stress free twisting system.The twisting form of phase conductor is also important for the following reason.The phase conductors are being allowed to slide freely over the messenger conductor during temperature fluctuation. It is also to be ensured that during sliding the insulation should not get scratches due to rubbing effect.During expansion and contraction, the phase conductors try to move toward the ends exerting additional stress at the terminating point or at the clipping point. By special twisting process such forces are neutralised. During installation and branching off, phase conductors can easily be loosened to crimp the connectors without straining and damaging the phase conductors.TestingAt Paramount Cables in house testing of raw materials & testing during processing at every stage is a must. There is no lapse allowed at any point where constant improvement is monitored from the beginning to the last stage.Aerial Bunch Cable though looks very simple in construction, its manufacturing technique should be such that the cable can accept and withstand all the severe operational hazards for all the times under any circumstances.Paramount Cables, understanding the inherent intricate operational significance of Aerial Bunch Cables, have oriented themselves to manufacture these cables for the power distribution system particularly forthe varied Indian conditions.ApplicationAerial Bunch Cables, 1.1 KV Volt Grade, are used for distributing power to individual consumers by utility service providers like electricity boards, elctricity distributing authorities. The cable is kept supported on poles. The line is tapped intermittently from any required position which enables itto be used in urban as well as rural areas alike.ConductorPhase or lighting conductor: Hard drawnAluminium H2 or H4 grades per 1S:8130 Messengerconductor: Aluminium Silica and MagnesiumAlloy used after treatment as per IS: 398 (part4)InsulationXLPE with Sioplas Technique applied by extrusion process.Identification of PhaseBy providing ridges on the insulation of phase conductors. One ridge for 1 st phase, 2 and 3 ridges for 2 nd and 3rd phases respectively. Neutral can have 4 ridges, if desired.Color of InsulationBecause the cable remains exposed to environment & sunlight (ultraviolet radiation) the insulation is mixed with a small amount of carbon black to stop deterioration of polythene due to U V radiation.AssemblingThe phase conductor along with the lighting conductor (where applicable) is twisted around messenger conductor.ConstructionThe phase conductor can be of single phase and also of three phases. A lighting conductor can be also incorporated to give supply to the street lighting. Messenger conductor supports the weight ofthe cable and keeps the assembly strung undertension.The phase conductor is made of concentrically stranded Aluminium Wires having 7 or 19 wires. The messenger conductor is made of specially treated Silica, Magnesium Aluminium alloy having 7 wires. The phase conductor and lighting conductor where applicable are insulated with XLPE (made of Sioplas Technology) compound. The messenger conductor, as per customer's choice is kept either bare or insulated. The phase conductor along with lighting conductor (where applicable) are twisted around the messenger, conductor (insulated or bare) and left as such. Sometimes as a special case a neutral conductor is also provided separately, if desired, by the user. Generally, messenger acts as earth as well as neutral.
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