1.1 KV Volt Grade, are used for distributing power to Individual consumers by utility service providers such as electricity boards and electricity distributing authorities. The cables are suspended overhead using electrical poles. The cables can be tapped intermittently from any required position, enabling them to be used in urban as well as rural areas.
Configuration
Single Phase or Three Phase systems with or without Street Light line.
Conductor
Phase or lighting conductor: Electrical grade Aluminium of H2 or H4 grade as per IS: 8130 Messenger conductor: Aluminium Silica and
Magnesium Alloy.
Insulation
XLPE with Sloplas Technique.
Identification of Phase
Ridges provided on the insulation of Phase Conductors: 1 ridge for the 1st phase, 2 ridges for the 2nd phase and 3 ridges for the 3rd phase.
The Neutral phase may have 4 ridges if required.
Colour of Insulation
As the cable remains exposed to environmental elements such as UV rays from sunlight, the insulation is mixed with a small amount of carbon black to prevent the deterioration of polythene.
Construction of Cable
The phase conductor can be of single phase or three phases. A lighting conductor can be also incorporated for street lighting. A messenger conductor supports the weight of the cable and keeps the assembly strung under tension.
Phase conductors are made of concentrically stranded Aluminium Wires having 7 or 19 wires. Messenger conductors are made of a specially treated Silica, Magnesium and Aluminium Alloy having 7 or 19 wires. Phase and lighting conductors may be insulated with XLPE compound of Sloplas Technology. Messenger conductors are kept either bare or Insulated. Phase and lighting conductors are sometimes twisted around the messenger conductor. In special cases a neutral conductor may also be provided separately. Generally, the messenger acts as earth and neutral.
This construction has additional advantages
Cables are lighter in weight
Easy to install
Can be installed on poles, on walls etc.
Easy to make terminations and branch off joints on live wire as well
Protection against power theft
Twisting and Laying
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, phases conductors can easily be loosened to crimp to the connectors without straining and damaging the phase conductor.