- it should have low value of specific resistance
- it should be light in weight and not brittle
- it should have low cost and high tensile strength
- all of these
Answer: 4. all of these
Explanation:
- High electrical conductivity i.e. low specific resistance.
- High tensile strength in order to withstand mechanical stresses.
- Low cost so that it can be used for long distances.
- Low specific gravity so that weight per unit volume is small.
Commonly used Conductor Materials:
- The most commonly used conductor materials for overhead lines are copper, aluminum, steel-cored aluminum, steel-cored copper, galvanized steel, and cadmium copper.
- The choice of a particular material will depend upon the cost, the required electrical and mechanical properties, and the local conditions.
- All conductors used for overhead lines are preferably stranded* in order to increase flexibility.
- In stranded conductors, there is generally one central wire and round this, successive layers of wires containing 6, 12, 18, 24 ...... wires.
- If there are n layers, the total number of individual wires is [3n(n + 1) + 1].
- In the manufacture of stranded conductors, the consecutive layers of wires are twisted or spiraled in opposite directions so that layers are bound together.
