Underground Cable Systems

SELT delivers high-voltage underground cable systems for both new and existing power networks, including projects involving existing infrastructure, complex site conditions and long-distance cable routes. Our expertise includes managing utility crossings, existing network interfaces and specialist installation activities.

High- and Medium-Voltage Underground Cable Installation

Our services cover the entire technical delivery process, from permitting and detailed design through construction planning to the installation of large cross-section high-voltage cables (up to 2,000 mm²), cable jointing and terminations, and substation connections.

Works are carried out in open trenches, ducts, utility tunnels and galleries, including crossings and specialist engineering works, using advanced technologies such as Horizontal Directional Drilling (HDD) to overcome obstacles without open-cut excavation. Every phase is managed through full document traceability and operational coordination, through to the integration of the infrastructure into the power network.

SELT is also one of only two contractors in Italy qualified to perform high-voltage cable jointing and terminations in-house. This specialist capability enables us to work on voltage levels from 30 kV up to 220 kV using our own highly qualified personnel, ensuring the precise installation of certified accessories and the long-term reliability of every electrical connection.

Scope of Services

Installation and removal of high-voltage underground cables

Handling and installation of large cross-section cables

HV cable joints and terminations (AIS/GIS) up to 220 kV

Cable connections to electrical substations and power plants

Installation and testing of fibre optic cables associated with transmission line

Installation of cable ducts, manholes and associated civil works

Supervision of cable installation and post-installation sheath testing

Support during electrical testing and final commissioning

Contact us to learn more about our underground cable installation services

Our Strengths

Specialist Teams

Our field crews include highly qualified technicians specializing in high-voltage cable installation, jointing, and terminations, with extensive experience working in complex environments and on energized transmission networks.

Dedicated Equipment

SELT operates a fleet of specialist equipment designed for handling large cross-section power cables and managing complex construction sites, ensuring precision, efficiency, and complete operational control.

Safety

Interface management, rigorous safety procedures and close coordination with all project stakeholders are integral to every cable installation project, in accordance with the company’s certified management systems.

I progetti di
Posa cavo

Trusted by Industry
Leaders

SELT works in long-term partnership with leading European power transmission operators and infrastructure developers. Our key clients include utilities and national transmission system operators such as Terna (Italy), Elia Group (Belgium), RTE France and TenneT (the Netherlands), as well as leading renewable energy investors including Sonnedix and IB Vogt.