Transmission Electricity Transmission: National Grid owns and operates an electricity transmission system of approximately 8,600 miles spanning upstate New York, Massachusetts, Rhode Island, New Hampshire and Vermont to customers that include local electric companies, municipalities and large commercial enterprises. Our US electricity transmission facilities operate at voltages ranging from 69 kV to 345 kV, utilizing overhead lines, nearly 90 miles of underground cable and 524 substations. We are the largest electricity transmission service provider in New England and New York by reference to the length of these high voltage transmission lines.

Canadian interconnector: National Grid owns and operates a direct current transmission line rated at 450 kV that is a key section of an interconnector between New England and Canada.


Northeast Operations