It’s a bimetallic conductors. The inner layers are composed by steel wires and the external layers are composed by hard-drawn aluminium AA1350-H19. The steel wires guarantee high mechanical performances.
This kind of conductor is used for medium and long spans thanks to the high value of specific mechanical resistance and good transport capacity.
The steel section will change to obtain the RTS requested. The modulus of elasticity of single steel wire is three time greater than an aluminium single wire.