Central Mass Transmission Improvement Projects

The S19 and T20 Asset Condition Refurbishment Projects (the Projects) are two separate National Grid initiatives occurring in south-central Massachusetts. Both existing lines are aged assets that require updates to improve system reliability, increase efficiency, and fix damaged and deteriorating infrastructure. Both lines will continue to operate at 69 kilovolts while the T20 line will have the ability to operate at 115 kilovolts to address future need.

The 11.3-mile long S19 ACR project starts construction in Summer 2025 with targeted replacement of eighty-five deteriorating wood structures with steel structures, sixty-eight wood pole structures with light-duty suspension structures and seventeen wood poles structures with custom steel dead-end structures on concrete caisson foundations. Dead-end structures will also be upgraded to carry 115kV loads to support a future rebuild of the entire line. In addition, there will be maintenance repairs at twenty-six structure locations. Construction is expected to continue through July 2026 with final restoration efforts lasting through Spring 2027. Project specific outreach has been ongoing in the communities of Millbury, Sutton, Oxford, and Webster, Massachusetts

The 17-mile long T20 ACR project is expected to start construction in Fall 2028 with a full replacement of 251 deteriorating wood structures with 251 steel structures. Construction is expected to continue from Fall 2028 until Summer 2031 with final restoration efforts lasting until Spring 2032. Public outreach in the communities of Spencer, Charlton, Dudley, and Webster, Massachusetts, has been ongoing. This Project is currently in the pre-construction activity phase and is awaiting permitting approvals.

Filing Oct 2025 - approval process takes 3 years.

Construction Complete - June 2031 according to new P6.