line conductor means a conductor forming part of a system and used for the transmission or supply of energy including so much of any service line as may be under the control of the undertakers
Copper was the preferred material for overhead conductors in earlier days, but, aluminum has replaced copper.
Why is it so? The short explanation is that aluminum is the all-around best material for overhead cables because of its unique properties. With its small density, low price, and high electrical carrying capacity, an aluminum wire is perfect for long-distance lines.