Dover to Needham Underground Cable Modernization Project FAQ

The Dover to Needham Underground Cable Modernization Project (UCMP) is designed to modernize and increase the capacity of existing underground transmission cable systems. The proposed project includes replacement of existing high-pressure fluid filled (HPFF) lines with cross-linked polyethylene (XLPE) electric transmission cables along a 1.3-mile existing route in the Dover, Needham and Westwood areas. The proposed route is between the Chestnut Street substation in Needham and Westfield Street substation in Westwood, along the Westwood-Dover town boundary. Construction is expected to begin in 2026 after receipt of all necessary permits and approvals.

Why is this project needed?

Eversource is taking a proactive approach to upgrade underground transmission lines to modernize infrastructure, boost capacity and better serve future demand. To learn more, visit https://bit.ly/EversourceUCMP.

What is the anticipated timeline of the project and how long will it take?

We plan to file a report with the Department of Public Utilities in Q3 of 2025. Upon receipt of all necessary permits and approvals, construction is planned to start in late 2026 and be complete as early as late 2028. Please note this timeline is dependent on approvals and subject to change based on unforeseen circumstances.

What is a transmission line?

Transmission lines carry high-voltage electricity between substations. For more information, please visit: https://www.eversource.com/content/residential/about/transmission-distribution/electric-distribution

What is the line voltage?

The voltage of the transmission lines will be 115-kilovolts (kV), which is the same voltage as the existing lines.

How many manholes will be placed along the route?

Approximately four manholes will be installed, three in Needham and one in Dover. Please note there will be additional handholes constructed for communication wiring access when necessary and these are sometimes called handholes.

What are the construction phases, generally?

Construction on an underground transmission line replacement project typically follows three different phases. The first phase of construction starts with work crews setting up safe work zones and often performing surveys and other field work. From there, work crews excavate the roadway, install vaults (often also called manholes), backfill and perform temporary restoration efforts. The second phase could involve trenching, installation of cable and temporary backfill. The third phase includes running cable between vaults and splicing.

Will Eversource backfill the roadway during construction?

Yes. As work progresses, crews will backfill pavement over completed work as part of the temporary restoration phase. Steel plates will also be utilized where needed. At the end of construction, a final review for restoration will be coordinated with local officials.

Will there be fluid in the new cables?

No. The new XLPE cables will contain solid dielectric cables rather than fluid. The dielectric fluid within the existing HPFF cables will be removed and the line retired in place as a spare.

What is the age of the existing transmission line?

The line was constructed in 1967, which makes it one of the oldest transmission lines on the Eversource system. System reliability warrants replacement of the current HPFF transmission lines.

What is the depth Eversource will be excavating to during construction to install the new transmission line?

The average excavation depth along most of the roadway will be five feet, while manholes will be about 15 feet deep. Please note that depths will vary due to underground conditions and to accommodate other existing utilities.

Will the project affect any water sources?

The project is not anticipated to affect any water resources. The replacement transmission line duct banks and associated construction workspaces are proposed to be located primarily within existing paved roadways.

What mitigation measures will be taken near the Charles River Crossing?

Soil erosion and sediment control devices such as straw wattles/bales, siltation fencing, and/or chip bales will be installed in accordance with approved plans, permit requirements and Eversource Best Management Practices (BMP) Manual. The use of timber construction matting will likely be used in environmentally sensitive areas or areas with uneven terrain. The installation of sediment control devices will be overseen by Eversource's environmental monitor. During construction, these BMP devices will be periodically inspected by the environmental monitor, and the findings will be reported regularly to Eversource's Environmental Specialist and Construction Supervisor. Soil testing will be conducted in accordance with Massachusetts standards throughout the project. Testing of existing line's fluid for polychlorinated biphenyls (PCB) will also occur.

Will there be road closures?

Currently, there are no planned closures along major roadways, and we are requesting police details to assist with any traffic impacts. Single lane alternating traffic will likely be implemented. Traffic management plans are dependent on input and approval from the affected Town(s).

More information?

For the most up to date information sign up for our email updates via constant contact by clicking here. For general information please visit our website at https://bit.ly/DoverNeedhamUCMP or contact our hotline at 833-836-0302 or email ProjectInfoMA@eversource.com