Mainline is a leading engineering solutions provider

Operating in Ireland, the UK and Scandinavia, Mainline provides a wide range of services from the Design & Build of Sub-stations, to construction of Airside Aviation Infrastructure, to Turn-key Wind & Solar Energy Solutions.

Mainline has a robust corporate management structure, underpinned by our ISO 45001, 14001, 9001 and cyber essentials accreditations as well as our Platinum Member Deloitte Best Managed Company status. We are also delighted to have been selected as an EY Entrepreneur of the Year Finalist 2022.

About Us

Delivering Internationally

Ongoing &
Recent Projects


In Q4 2023 Mainline commence work on the 7 Turbine Wind Farm in Co Clare for Energia.

The scope of work consists of the design and build of the 38kV Substation, Collector cable to the 7 turbines, and 13km grid connection (6km of Overhead Line and 7km of Under Ground Cable) to the Booltiagh Substation. The project duration is approximately 18 months.

In 2023 Mainline completed 6 Solar Farm Substation & Grid Connection Design & Build projects, and is currently delivering 11 similar projects of varying sizes, for a number of different Clients.

Mainline have been contracted by Atlantic Projects Company (APC) to carry out the design, supply and install of various element of civil and electrical works associated with a double 275kV grid connection, connecting the existing NIE 275kV substation within Kilroot Power station and the new 275kV GIS switchgear.

Site: Murley Mountain Wind Farm, Fivemiletown, Co. Tyrone

Work Scope: Full EBoP (Electrical Balance of Plant) scope with 6 x Turbines to be energised following the design, procurement, and construction of the substation, over headline and underground cable networks. PSCS, Testing and commissioning will also be delivered by Mainline prior to the energisation of the site.

Mainline are currently delivering a significant second Wind Farm project in Northern Sweden, Phases 1 & 2 of Markbygden Wind Farm, part of the overall 1,002 Turbine Markbygden cluster, close to Pitea.

Scope of work includes:

  • Full Electrical Design for Markbygden Wind Farm (Phases 1-3) for a total of 137 wind turbines c/w 680km of 36kV collector system.
  • Currently delivering Phases 1 & 2 EBoP works for 69 wind turbines comprising
  • Over 350km of MV cable,
  • Over 90km of associated Earthing conductor
  • Over 90km of telecoms fibre
  • Installation of cable jointing, terminations and testing/commissioning of the 36kV collector system
  • Wind turbine earthing installation for 69 wind turbines
  • Design, supply, installation and commissioning of 9 external Switching Stations all fitted with 36kV switchgear, protection and LV requirements.
  • Managing, liaising and coordinating on site activities

We successfully delivering the 73 Wind Turbine Electrical Balance of Plant (EBoP) for Hästkullen Wind Farm, in the Nysäter wind park, close to Sundsvall. The scope of the project included:

  • Engineering and construction (design, optimisation and build) of the 36kV collector cable to 73 wind turbines.
  • Over 95 km of associated civil works, trenching and backfill, through a variety of terrains from wetlands to rock, including a number of directional drills.
  • Over 95 km of associated earthing conductor works.
  • Over 155km of fibre telecommunication works.
  • Installation, cable jointing, testing, commissioning and energisation of almost 455 linear km of 36kV cable.
  • Various additional civil works, including the construction of an access road.

The new North Runway project in Dublin Airport is the most substantial airfield project in Ireland for a long time, and upon completion it will become a vital piece of national infrastructure, significantly increasing the capacity of Dublin Airport. Mainline are the Lead Electrical Contractor on this large scale Aviation project, and our scope includes the supply and installation of the following:

  • Over 340km of primary cable in ducts adjacent to the runway
  • Over 135km of secondary cable (feeding each light)
  • Termination of primary and secondary cables
  • Over 2,500 Transformers in manholes
  • Over 28km of Fibre Optic Cable
  • Over 27km of MV Cable
  • Over 11km of 50 Pair Copper Telecoms Cable
  • Over 5 km of Earth Cable
  • Over 100 Runway/Taxiway signs
  • Over 1,800 shallow bases for Airfield Ground Lights
  • Over 2,200 aviation lights including:
    • Runway lights
    • Taxiway lights
    • PAPI lights
    • Approach lights
  • Complete fit-out of 2 substations including:
    • Mechanical & Electrical fit-out
    • HV Switchgear
    • Circuit breakers
    • HV Transformers
    • Constant Current Regulators (CCRs)
    • Back-up generators
    • Distribution Boards
    • Fire Suppression Systems
    • Building Management Systems
    • UPS’s
    • Lighting protection Systems
    • Security Systems

ESB 38 to 110kV Substation Framework.
In 2022 Mainline began delivering projects on this ESB 38 to 110kV Substation Framework, which encompasses a broad range of works from G1/G3 connections (New housing and industrial unit connections), Mini Pillar and Magnafix replacement to Live 38-110kv substation maintenance and refurbishment projects. The framework runs for 7 years across the 26 counties.

ESB Substation Civils Framework.
Since 2015 Mainline has delivered civil upgrade works to over 150 ESB Substations. In 2023 Mainline won a place on the new version of this framework. The framework runs for 7 years across the 26 counties.

ESB 38 to 400kV Substation Framework.
In late 2023 Mainline won a place on the ESB 38 to 400kV Substation Framework, which encompasses a broad range of works from HV Jointing to HV Substation asset replacement and maintenance. The framework runs for 7 years across the 26 counties.

Cork Non-domestic Water Metering – D&B and O&M
Mainline delivered the design, build and installation of over 20,000 non-domestic water meters in Cork. Mainline then Operated and Maintained (O&M) the 20,000 non-domestic water meters on behalf of Cork County Council / Irish Water. The O&M contract ran for 15 years to 2021, and included the capital replacement of the 20,000 installed meters, all of which were replaced between 2016 and 2019. Mainline continues to read all of the meters for Irish Water.

Irish Water Domestic and Non-Domestic Metering Reading – Connaught & Ulster
In 2020 Mainline was awarded a 5 year Contract to read Irish Waters Domestic and Non-domestic Meters in areas of Connaught & Ulster. Overall this involves reading over 5,000,000 AMR and Manual meter reads, as well as providing various other support and investigative services.

Irish Water Domestic Water Metering D&B
In 2017, in conjunction with our JV partners J Murphy & Sons, Mainline completed delivery of meter installations services to Irish Water for two of the eight domestic water metering regions. The two regions, the South West and West, included the installation of over 262,000 domestic water meters, with a combined contract value of circa €100m. Installation of the water meters commenced in September 2013, less than 6 weeks after signing of contracts, and peaked at almost 400 direct and indirect staff across Cork, Kerry, Limerick, Tipperary, Clare and Galway.

Our Clients