Mapperley & Gedling Cable Works
Project Location:
Mapperley & Gedling
Client Name:
National Grid Electricity Distribution
Project Description:
OCU delivered the upgrade of ageing 33kV fluid-filled cable circuits between Nottingham East 132kV Substation and the Gedling and Mapperley primary substations, acting as Principal Contractor for the works. Installed in 1975, the existing cables were prone to leakage and posed environmental risk. The project involved installing two new double-circuit 33kV cable routes serving Gedling and Mapperley Primary Substations, alongside the decommissioning of the existing oil-filled assets. Works included route feasibility studies, urban civil engineering, duct installation, cable pulling, jointing and commissioning across constrained city routes.
Key Stats:
2 x double-circuit 33kV XLPE cable routes
400mm² Cu XLPE cables installed in trefoil formation
500m cable drum lengths used to reduce jointing frequency
16 x intermediate joint bays
2 x point-of-connection bays
7 Months
Duration
Challenge
Identifying the most viable cable route between two competing route options while maintaining constructability and programme certainty
Replacing deteriorating oil-filled cables that were prone to leaks
Delivering works across busy urban corridors with significant traffic and parking constraints
Managing multiple stakeholders including Nottingham City Council, highways authorities and local residents
Navigating congested underground utilities including gas mains, sewers and electrical assets
Solution
Completed detailed feasibility assessments and route optimisation studies to determine the most efficient alignment
Developed a hybrid route solution combining elements of the two routes to minimise land risk and improve constructability
Installed fully ducted infrastructure to support future network reinforcement and maintenance
Implemented coordinated traffic management and streetworks planning across residential and urban areas
Decommissioned the existing oil-filled cable system safely, including controlled removal and disposal of insulating oil
Delivered the scheme through OCU’s integrated self-delivery model, combining civils, cable installation and engineering expertise
Outcome
Replacement of ageing oil-filled circuits with modern XLPE cable systems, significantly reducing environmental risk
Improved long-term network reliability and operational resilience for NGED
Successful delivery within programme while operating in a highly constrained urban environment
Strong collaboration with local authorities and stakeholders, minimising disruption to residents and businesses
Future-proofed ducted infrastructure enabling easier maintenance and potential network upgrades
