National Grid will hold a walk-in open house in Andover on Wednesday, Sept. 30, to detail a $118 million power-line replacement project.

The utility plans to swap out aging wood poles for steel structures along a 32-mile, 345-kilovolt transmission corridor that runs through town. The session runs from 6 to 7:30 p.m. at the Andover Municipal Services Building meeting room, 5 Campanelli Drive. There will be no formal presentation. Residents can stop by at any point during the 90 minutes to ask questions and review project details.

National Grid is calling the work its Asset Condition Refurbishment Project. It covers two transmission lines, Lines 394 and 397, stretching from Haverhill's Ward Hill Substation north to the New Hampshire border and south to Tewksbury, as WHAV first reported.

Both lines were built in 1989. The 148 wood structures among the corridor's 301 total structures average 36 years old. A National Grid filing with ISO New England, the regional grid operator, cites cracking, shell rot, insect damage and woodpecker holes as reasons for replacement.

Of those wood poles, 127 are rated for planned replacement and 21 more are flagged as opportunity replacements. None require emergency replacement.

The project will replace those poles with light-duty steel H-frame and monopole structures. Crews will also build new access roads and work pads and install optical ground wire to improve reliability and allow remote troubleshooting between substations.

National Grid representative Rafael Panos presented the plan to ISO New England on July 28. The preferred option carries an estimated price tag of roughly $117.87 million, with a stated accuracy range of plus or minus 25 percent. Major construction is scheduled to begin in the first quarter of 2027, with the project expected to be in service by the fourth quarter of 2028.

Besides Andover, the work is planned in Dracut, Methuen, Haverhill, Boxford, Georgetown, Groveland, West Newbury, Merrimack and Amesbury.

The project comes as Andover continues to grapple with power reliability. An Andover News analysis published in January found that Andover ranked first statewide among National Grid communities for total customer-outage hours over the prior three years. National Grid officials presented outage data to the Andover Select Board in January and pledged targeted fixes.

Residents who cannot attend the open house can call National Grid at 781-263-6286 or email [email protected].