City Light Plans Silicone Cable Injection In Parts of Service Territory

Seattle City Light will start another project this October to enhance the reliability and extend the life of aging underground electrical cables in parts of Shoreline, Lake Forest Park and Seattle by injecting them with silicone.

City Light’s contractor, Novinium, will test and where possible, inject underground cables with silicone to fill cracks in the cable insulation to prevent outages. This work will extend the life of the cable for an additional 25 years and improve electrical reliability. If cables are not suited for injection, they will be replaced at a later time.

Please refer to the construction notification fliers for approximate construction areas:

This project is expected to start in early-to-mid October 2015 and extend for approximately six weeks. Work hours are scheduled for Monday to Friday, from 8:30 a.m. to 4:30 p.m. During construction, customers should expect some traffic and parking impacts in the immediate area. Crews will be careful to try and maintain access to driveways.

Several maintenance outages are required for this work. Affected customers will be notified the Thursday before the following week’s outage. The outage date and time will be specified on the notification.

Past cable injection projects in neighborhoods such as Sandpoint, Queen Anne and Delridge 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.

Customers can contact the following Electrical Service Representatives for more information:

For more information, please visit our construction website:

Seattle City Light Completes Electrical System Upgrade on East Denny Way Near East Broadway

The newly installed vault on East Denny Way.

Seattle City Light crews recently completed civil construction work on East Denny Way between Harvard Avenue and Broadway on Capitol Hill. The work will improve electric service reliability and will help to reduce the number of unplanned outages in the area. 

City Light’s construction work began June 16, 2014, and was completed on schedule two weeks later. Crews trenched and installed conduit between an existing underground electrical vault located in the sidewalk and a utility pole roughly 20 feet away. The excavation and conduit installation were the first steps to increase electrical capacity from 4 kilovolts to 26 kilovolts to customers in the area. Crews have also restored the asphalt and concrete affected by the trenching and conduit installation.

The construction and related upgrades are important to improving the electrical service reliability to City Light customers and are a vital component of the utility’s Strategic Plan.

At a later date, crews will install new electrical cable. The cable installation will take several days to complete.

For more information about this and other City Light construction projects, please visit

About Seattle City Light
Seattle City Light is the 10th largest public electric utility in the United States. It has some of the lowest cost customer rates of any urban utility, providing reliable, renewable and environmentally responsible power to nearly 1 million Seattle area residents. City Light has been greenhouse gas neutral since 2005, the first electric utility in the nation to achieve that distinction.