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Frost Bridge to Campville 115-kV Transmission Project

Construction on a new transmission line and substation upgrades in northwest Connecticut began in November 2016. These improvements will strengthen the electric system and provide customers with the reliable power they need – while meeting national and regional reliability standards.  

At Eversource, we're always working to serve you better. The new 10.4-mile line crosses the towns of Watertown, Thomaston, Litchfield, and Harwinton to connect Eversource’s Frost Bridge substation in Watertown with its Campville Substation in Harwinton.  The line is located entirely within Eversource’s existing transmission line right of way.  In addition, new equipment is being installed at both substations.

We are also reconfiguring two 115-kV lines where they cross the Naugatuck River at the Litchfield/Harwinton town lines. This reconfiguration will increase reliability by allowing each line to be supported by its own set of structures.


* Click map to enlarge.

Line & Substation Construction

Construction on the new transmission line and upgrades at the Frost Bridge and Campville substations began in November 2016.

Hours of construction will typically be 7 a.m. through 7 p.m., Monday through Saturday. Due to unforeseen weather or other circumstances, the workday may be extended or work may be performed on a Sunday. 

Project Facts:

  • Route length: Approximately 10.4 miles
  • Location: Watertown, Thomaston, Litchfield and Harwinton, Connecticut
  • Line voltage: 115,000-volt (115-kV) overhead transmission line
  • Substation: Substation upgrades at both Frost Bridge substation in Watertown and Campville substation in Harwinton
  • Siting review by: The Connecticut Siting Council (CSC)

Estimated Timetable:

  • Municipal Consultation Filing (MCF): September 2015
  • Public open houses: September 29 and 30, 2015
  • Connecticut Siting Council (CSC) Application filing: December 23, 2015
  • CSC Public Hearing: March 1, 2016
  • CSC approval: April 14, 2016
  • Development & Management Plan approval: September 16, 2016
  • Start of construction: November 2016
  • Estimated in-service date: Mid-2018

Connecticut Siting Council Application Filing

For an electric transmission line project, such as the Frost Bridge to Campville 115-kV Transmission Project, the Municipal Consultation and Application Filing phases are part of the siting regulatory review process, as defined by the Connecticut state statutes. 

On April 14, 2016, the CSC voted to approve the Certificate of Environmental Compatibility and Public Need (Application) for the construction of the Frost Bridge to Campville 115-kV Transmission Project.

The project’s construction plans, called Development and Management (D&M) Plans, were also submitted to the CSC for approval. On September 16, 2016, the CSC voted to approve the project’s D&M Plans.

On January 10, 2017, an update to the D&M Plan, Volume 3 (Maps) was submitted to the CSC for approval.


Beginning with municipal briefings and community outreach efforts related to the Frost Bridge to Campville 115-kV Transmission Project, we have made a concerted effort to engage town officials, residents, businesses and other stakeholders to inform, answer questions, and listen to concerns about the project.

We will continue these outreach efforts throughout construction.

Contact Information

For more information about the Frost Bridge to Campville Project, send an email to or call 800-793-2202.