NStar Goes Underground to Improve Reliability

The usual cause for electric power failure: wires forced down as a result of storms or highway accidents. The immediate reaction for power companies: isolate the fault and supply power to the affected areas from redundant sources, usually from adjacent communities. The Outer Cape past Wellfleet is especially vulnerable to such failures because residents and businesses do not have a redundant supply of power. Historically, the redundant transmission line has stopped at the Wellfleet/Truro town line, and from there through Truro and on to Provincetown only the primary power line has been at the top of the power-poles along Route 6.

Starting this fall, NStar will install a new underground loop for the 11.8 miles from the Wellfleet–Truro town line to Snail Road in Provincetown. This loop, furnishing redundant power, will be alongside Route 6 (almost all the way) and will not cause any of the existing poles to be taken down. It also will not require an eleven-mile long trench to be dug!

This high-voltage, high-power line will be installed underground by horizontal directional digging between two-foot square pits, variously 200 to 500 feet apart, with the cables drawn through horizontal holes. Altogether there will be some 115 pits connected. This technology was developed over the last couple of decades as hydraulic fracking was developed.

The route will be entirely within the highway right-of-way (the “layout”) and will not be on any private property. It will be on the West side of Route 6 but will include South Hollow Road to Shore Road, where it will stay on the East side. This is because there has to be a transformer to maintain the voltage, and the transformer will be mounted on the Truro Substation which is near Babe’s Bakery. Then the loop will be brought out along Standish Road to Route 6 and proceed into Provincetown.

NStar has presented its plans to the Truro Conservation Commission and the State DEP for permits to work near wetlands, conservation areas, etc. The plans are available for examination at the Conservation Commission office in Town Hall.

When the construction is complete there will be those 115 new manhole covers flush with the ground as the only evidence of the work, except for fewer – and shorter – power outages.