City Light Completes Cable Injection in Lake Forest Park

Earlier this fall, Seattle City Light completed its silicone cable injection work in Lake Forest Park. The project began in September 2016 to enhance the reliability and extend the life of aging underground electrical cables in parts of Lake Forest Park by injecting them with silicone.

City Light’s contractor, Novinium, tested and where possible, injected about a mile of underground cable with silicone to fill cracks in the cable insulation to prevent outages. This work extends the life of the cable for an additional 25 years and improves electrical reliability.

Example photo of typical cable injection work.

Approximately 50 percent (half a mile) of the total underground cable from this project was suited to injection. The remaining 50 percent of cable was not suited for injection and will be replaced at a later time.

Past cable injection projects in areas such as Shoreline and Seattle’s Capitol Hill neighborhood have succeeded in extending the lifespan of aging cables and improving reliability at a lower cost than replacement. A 2011 cost comparison showed that the average cost of cable injection was $25, compared to $248 for cable replacement.

For more information about this project and other City Light construction projects, please visit our website: