They normally have one or two electrical circuits, each consisting of three phases. Depending on the number of conductors in each phase, they are called simplex (one), duplex (two), triplex (three), or quadruplex (four).

The most commonly used conductors in our transmission grids are ACSR, aluminium conductor steel-reinforced, which can reach a maximum continuous operating temperature of 90 ºC. The temperature of the conductors determines the sag and the curvature of the cable between two towers. Both are directly related to the line's transmission capacity; a higher temperature means greater sag and more capacity to transmit electricity.

Throughout their route, the conductors and ground wires are supported by the towers. The predominant type is a self-supporting lattice structure with independent foundations for each of the four legs that support the structure.

Additionally, the conductors are attached to the towers using insulator strings. These insulators, made of glass or composite materials—depending on the contamination level of the installation area—support the cables and electrically isolate them from the tower, preventing potential electrical bypass.