The vast majority of cables used for these lines have cross-linked polyethylene dry insulation (XLPE), with fluid oil insulation being a residual technology.

The conductive sections of these cables are made of copper or aluminium, depending on the required transmission capacity of the circuit.

The usual method of laying these cables involves embedding them in concrete prisms constructed in trenches, where joints are installed in specific chambers for this component.

The most common screen connection methods are single point and cross bonding, aimed at eliminating or minimising current circulation through the cable screens to prevent heat generation and thus not affect the circuit's transmission capacity.