What are Hot and Black Conductors in Transmission Lines

Hot Conductors are conductors in transmission lines which can high currents through normal cross section. They can thus tolerate high current density.  
Hot Conductors are made of special high grade aluminium to which is added many other elements particularly zirconium.  
On further processing, a microstructure is created which gives the alloy a high recrystallization temperature.  This enables the conductor to withstand the high temperatures generated by the high currents.  

A hot conductor can carry about 50% more than a normal conductor of the same cross section.

By giving a black coating of polyurethane to the conductor, the radiation of the heat is increased.  This permits the conductor to carry current up to 70% more than a conventional conductor.