Section 31 Transmission Line Rebuild

Central Maine Power (CMP) will begin rebuilding and modernizing its five mile Section 31 Transmission Line in Spring 2026, which serves Brunswick, Topsham, and parts of Harpswell. The line runs from the Topsham 115kV Substation near Crooker to the Brunswick West Side Substation on Barrows Drive. 

Project Scope

Increase reliability through infrastructure upgrades

This project includes reducing wood structures with slightly taller galvanized steel poles and installing a compact, covered tree wire system to improve reliability and reduce outages from trees and faults. 

Construction is anticipated to start in Spring 2026 and continue until the end of the year. CMP will construct the new transmission line while the existing line remains in place. The existing line stays energized during construction to avoid service interruptions as it is the only source of electrical power for area customers. New, slightly taller galvanized steel  poles will be installed and a compact, covered tree wire system will be strung to protect the line from tree contact, thus improving reliability and reducing outages from trees and faults. 

Once the new line is completed and energized, the older transmission line will be removed. 

 

Section 31 Transmission Line Route

 

Benefits to Customers

  • Replaces aging infrastructure
  • Expands capacity to meet growing electricity demand
  • Improves reliability to more than 8,000 customers in Topsham, Brunswick, and Harpswell
  • Enhances resiliency during major, stronger storms, such as those Maine has experienced in recent years 
  • Supports clean energy technologies such as heat pumps and EV chargers

 

Outages

No scheduled outages are planned, and the current line will remain energized throughout construction. 
 

Work Hours and Noise

Most work will occur during daylight hours in accordance with town ordinances. Some night-hours work, particularly in the Topsham Fair Mall area, and across the interstate and the Androscoggin River, or weekend work may be required. All work is weather dependent.

Construction noise will be present, including vehicle backup beeping sounds, heavy equipment vehicles, pounding, and other sounds associated with digging holes to install new structures.

 

Construction Zone Safety

At CMP, your safety and that of our crews are top priorities. Please follow construction signs regarding construction zones, path closures, traƯic pattern changes, or parking lot closures. 

 

Visual Renderings

We have created visual renderings that depict structures and wires that will be installed in CMP’s Section 31 corridor. They do not show the final work on vegetation, fences, and other non-transmission structures.

Contact us

More information

CMP has a perpetual easement of 100 feet that has been in place since the 1950s. The current Section 31 transmission line is in the middle of the easement.

As part of the upgrade, a new line will be installed oƯset from the existing line and within the established boundaries of the 100-foot area. The easement does not change. The width and location of the existing corridor will remain the same. 

CMP crews will be accessing the transmission line corridor via roads where CMP has access rights or legal agreements with property owners or towns. CMP will contact some adjacent landowners to discuss access rights.

CMP will secure all necessary permits and approvals from the Maine Department of Transportation, MaineDepartment of Environmental Protection, U.S. Army Corps of Engineers, and Town of Brunswick.

CMP crews will lay wood mats in environmentally sensitive areas. The mats disburse the weight of construction vehicles to protect the land below them.

CMP positively collaborates with communities and recreation groups to balance safe access to our corridors with our need to reliably maintain the electric grid. Many of our Brunswick neighbors actively use paths in the Columbia Street area that are near our transmission line or cross its corridor. For your safety, we will keep you informed about construction activity. 

CMP’s Community Relations team is working with the Town of Brunswick and Brunswick School Department to send notifications, including letters, alerts, and posted signs. Also, we're coordinating our work around school and sports schedules, bus stops, and people walking to/from schools. Safety fencing will be used in some areas.