HV Cables

HV Cables

Mainline has established itself as a leader within the industry for the installation of underground cables from 20kV to 220kV. We offer the complete service of cable installation, cable jointing and cable testing. We are approved by ESB Networks to joint cables up to 220KV.

We have developed our cable installation systems to allow us install underground cables over distances in excess of 1,100m. This results in fewer joints and joint pits on the cables, enabling us to offer value engineering solutions to our clients, as well as a significant time saving.

Mainline also provides a full underground cable duct design and installation service, where we select the optimum duct type and size, to ensure that cable pulling tensions are within cable manufacturers guidelines, whilst also ensuring that future electrical losses are kept to a minimum. All our cabling pulling and duct proving equipment has been fitted with computerised data recorders which are Wi-Fi enabled for real time information sharing.

Sample Projects

Crory 110KV Sub-station To Ballycadden/Ballyduff Windfarms. Installation of 30 Km of 3x 400sq. 20KVv underground cable and installation of communication fibre optic.

38KV grid connection, installation and jointing of 20mm of 38 KV cable and communication fibre optic from Barranafaddock Wind Farm to Barrymore ESB 38 KV substation.

  • Knocknalour WF to Crory 220kV Substation (12km)
  • Gortahile WF to Carlow 38kV Substation (18km)
  • Dromdiveen WF to Glenlara 110 kV Substation (19km)
  • Garrycummer WF to Cauteen 110 kV Substation (17km)
  • Gibbet Hill WF to Crory 220kV Substation (14km)
  • Grouse Lodge WF to Rathkeale 110kV Substation (6km)
  • Bawnmore (1&2) WF to Macroom 110kV Substation (10km)
  • Boggeragh WF to Glashavoon 220kV Substation (8km)
  • Ballyvane WF to Ballylickey 110kV Substation (25km)
  • Knockwarriage WF to Trien 110kV Substation (33km)
  • Letterfrack WF to Salthill110kV Substation (20km)
  • Ballybeagh WF Thurles – Blanchfield 38kV Substation (26km)
  • Cordal to Scartaglin 38kV Grid Connection (12km)
  • Tullanamoyle II and III 20kV Grid Connection (8km)
  • Ballycumber WF Kilmagig – Mangans 38kV Substation (27km)

In 2024, Mainline completed the medium-voltage (MV) cable grid route from Dardistown Substation to the solar farm located adjacent to Dublin Airport. The project involved the installation, testing, and commissioning of over 30 km of 400mm² MV cable, nine joint bays with associated pit furniture, and three substation terminations (two in the solar park and one at Dardistown).

A significant portion of the route was constructed within the active airfield environment, requiring stringent safety and operational coordination. Extensive ITP documentation was submitted through the DAA’s ACC portal. The project was delivered on time and in line with all quality expectations.

Yellow River is a 29-turbine wind farm located in County Offaly, near the village of Rhode. The wind farm is connected to a newly constructed 33kV substation, developed in parallel with the wind energy infrastructure.

Mainline’s scope of works was delivered in 2024 and included the design, procurement, installation, jointing, and termination of the medium-voltage (MV) collector system within the turbines.

In addition, Mainline carried out the installation and testing of the fibre optic network, foundation earthing, and the wind farm counterpoise earthing system. The project involved the installation of approximately 190,000 metres of MV cable.