Projects
132 kV Project
Crawley Data Centre
Durkin and Son Project Managed the offsite scheme as Principal Contractor for our client Freedom.
Case Study 1
The construction of Digital Realty’s new data centre at Manor Royal, Crawley required the delivery of an N1 secure 132kV dual circuit power connection from the point of connection at Three Bridges Grid. Freedom, acting as Principal Designer and Tier 1 contractor, appointed Durkin & Sons to design and deliver the 4km offsite contestable works, providing 50MVA of capacity via two diverse 132kV cable routes built to UK Power Networks (UKPN) adoptable standards.
The project involved detailed feasibility analysis, extensive stakeholder engagement, complex urban construction, and strict compliance with UKPN engineering specifications. A combination of amenity land and dense urban environments required careful planning including liaison with local authority for opening and closing notices for excavation, duct installation, joint bay construction, and cable pulling operations, all while minimising disruption to residents, businesses, and road networks.
Durkin & Sons successfully delivered the offsite infrastructure, including duct installation, 132kV XLPE cable installation, fibre communications, joint bay construction, and permanent reinstatement, ensuring that both circuits were fully compliant, fully documented, and ready for adoption by UKPN. The project was executed with a strong focus on safety, environmental considerations, risk management, and collaborative planning with local authorities
33kV Circuit Install
Velmore Dual
The Velmore Project comprised 33kV dual HV circuit design in a mixture of urban and rural landscape.
Case Study 2
Durkin and Sons scope
> Principal contractor duties.
> Detailed route design & delay surveys.
> Excavation of urban highways, installation of ducts, backfill and permanent reinstatement.
> Cable pulling design calculations and jointing of all 33kV cables.
> Testing and cold commissioning of laid cables.
> As laid records.
> Traffic management.
> Temporary works.
> HDD Design and deliver.
> Local authority and other stakeholder management.
The scheme comprised a mixture of agricultural land (1.5km) and highways (11.5km) route. The highways sections were very urbanised, requiring close and ongoing liaison with the local authorities and Highways England.
Due to the length and complexity of the route we expected and encountered, several special engineering difficulties (SEDS), that were successfully overcome with close client and stakeholder liaison. These included our proposal for changes to the original route design to ensure delivery was successful through the introduction of directional drilled bores under Monks Brook, a local watercourse.
Close liaison with the local community and other stakeholders, such as emergency services and local businesses, was a vital requirement, resulting in a complimentary letter from one local business.
33kV cable installations
SSE Bordon
The SSE Bordon project established a comprehensive and self sufficient delivery model in which Durkin and Sons was fully responsible for operational resource, team management, plant provision, and on‑site supervision.
Case Study 3
The SSE Bordon project is a two‑year delivery programme valued at approximately £2.5 million per year, commencing in April 2023. For this project, the Employer (SSEN) acted as both principle contractor and principle designer, Durkin and Sons provided the operational resource to undertake the feasibility work, civil and overall project oversight, executing the full installation of the 33kV cable system and associated civil works.
The scope included excavation, duct installation, cable installation and associated permanent reinstatement activities. The scope included fibre optic cabling across the defined cable routes. Durkin and Sons supplied and managed all labour, plant, tools, PPE, transport, project staffing, and welfare, ensuring that SSEN policies and safety procedures were fully observed. Day-to-day site management—including supervision, team administration, programme adherence, and performance was also provided by Durkin and Sons.
This project supported SSEN’s ongoing network reinforcement and reliability enhancement programme, enabling safe, timely, and flexible mobilisation of specialist cable installation teams was provided by Durkin and Sons.
33kV cable installations
SSE Shripney
Operational delivery followed SSEN’s proposed installation incorporating both open cut trenching and 300m HDD sections. The existing 3core fluid filled cables were cut and jointed to the new XLPE cables using Groove transition joints, maintaining circuit integrity and enabling the retirement of the overhead line.
Case Study 4
SSE’s Shripney–Argyle Road 33 kV reinforcement project involved replacing approximately 700 m of existing overhead line with an underground XLPE cable solution to improve network resilience, reliability, and environmental integration in the Bognor Regis area.
The project introduced 370 m of new Nexans 630 mm² aluminium 33 kV XLPE cables, which were single point bonded and connected between existing 240 mm² Cu fluid filled cables from Argyle Road Substation and existing 400 mm² Al XLPE cables running toward Shripney Substation.
Circuits 1 and 2 will continue to operate as a dual circuit route with winter/summer continuous ratings of 30.4 MVA (532 A), with each circuit required to carry full load under outage conditions.
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