Fluid Filled Cables

Like many international utilities, ESB Networks install underground cables in urban locations where it is not feasible to construct overhead lines. Fluid filled cables were installed on ESB Networks distribution and transmission systems between 1950 and 1989. ESB Networks plan to replace all fluid filled cables by 2035. Replacement is prioritised based upon environmental risk for the circuit involved. 

• The conductor transports electrical power.
• The insulator is used to stop electrical power from the conductor escaping.
• The earth sheath ensures the cable operates safely.
• The other covering serves as a protective coat around the cable.

Cable History

Like all technologies, underground cable technology developed with improvements in materials, science and engineering. There have been three distinct cable technology periods. 

Fluid Filled Cables - Replacement Programme

Recognising the environmental challenges in operating and maintaining FFCs, ESB Networks started a fluid-filled cable replacement programme in 2005. So far, 20 % of FFCs have been replaced, removing the source of 40 % of the previous cable fluid leaks from the system. At present, there is approximately 177 km of FFCs on the Transmission and Distribution Electricity Networks. We have a number of active fluid filled cable replacement projects at construction stage and additional projects at route selection stage.

Such major infrastructural projects involve:

• Scheduled outages for which businesses and families adjacent to these works must be informed and given adequate notice
• Securing temporary road opening licences
• Traversing third party infrastructure, services and major road, rail, waterway crossings
• Temporary extended road closures
• Significant trench excavations for new plastic insulated cable and cable replacement
• Jointing works
  

The projects will be undertaken on a phased basis in populated urban areas with significant traffic volumes. Ongoing engagement with relevant stakeholders is vital to ensure efficient and successful delivery of these cable replacement projects.

ESB Networks has now committed to an accelerated investment programme with the Commission for Regulation of Utilities (CRU). An environmental assessment informs both the schedule and the timing of individual cable replacements.

As part of the Price Review Five (PR5) determination, CRU approved Distribution and Transmission FFC Replacement projects totalling 98 km. The remaining FFCs are planned to be replaced over subsequent Price Reviews subject to CRU approval.

Information On Fluid-Filled Cables | PDF 1MB

Repairs - Map