Why Are We Doing This Project?

As part of our ongoing commitment to deliver reliable energy and superior service to our customers, we are proposing to replace existing 115-kilovolt (kV) high pressure fluid-filled (HPFF) underground transmission lines with new 115-kV cross-linked polyethylene (XLPE) transmission lines. 

The underground transmission lines 1270 and 1337 in Danbury were built in 1976, and are past their useful life expectancy.​ Replacing the existing HPFF with XLPE will modernize the existing transmission system and increase reliability.

The approved project is part of a larger program we are conducting throughout our service territory in Connecticut and Massachusetts called the Underground Cable Modernization Program (UCMP).

Where Is This Work Being Done?

The 1270 and 1337 underground transmission lines run from Triangle Substation to Middle River Substation, both in Danbury, Connecticut. 

This work is split into two segments between Middle River Substation on Middle River Road, and Triangle Substation on Triangle Street.

• Segment 1 will began October 2025, between Middle River Substation and I-84. Roads affected include Westville Avenue Extension, Gregory Street and Franklin Street Extension.
• Segment 2 will begin in late spring/early summer 2026, between I-84 and Triangle Substation. Roads affected include 9th Avenue, Franklin Street, Garamella Boulevard, Osborne Street, Taylor Street, Triangle Street, White Street and Wildman Street. Once the second phase of work begins, both segments will be underway simultaneously. 
  

*Click map to enlarge 

About this project

• Route length: 4 miles
• Line voltage: 115 kilovolts (kV)
• Siting review by: Connecticut Siting Council (CSC)

Construction Updates

Over the past two years, we have partnered with the City of Danbury to align construction with local roadwork, coordinate across departments, and maintain ongoing communication with more than 800 residents along the route. 

Work in close proximity to individual residences and businesses typically lasts a few weeks. Our teams will coordinate with residents to maintain access within the work zone and minimize impacts to daily activities.

Abril

We will continue construction on the underground transmission line portion of the project focused along Franklin Street and Westville Avenue. This work will be done within roadways and performed in segments. 

Traffic patterns may be altered. Motorists may experience some delays with temporary closures.

Pictured below: (left) Vault installation prep on Gregory Street and (right) traffic pattern set up on Franklin Street exit. 

Siting Review

This project requires a petition filed with the CSC that was filed on September 26, 2024. Environmental permits will also be required from state and federal agencies. 

Community Outreach

We're committed to engaging city officials, residents, businesses, community groups and other stakeholders about project activities through municipal briefings, mailings, virtual meetings and door-to-door outreach.

Our team strives to incorporate local feedback into the project's development wherever feasible. Team members will remain engaged with the community throughout phases of the project.

• Start of construction letter (en Español, em Português)