The Norris Public Power District's electric system is a sub-transmission and distribution system consisting of 676 miles of 69 kV or 34.5 kV sub-transmission lines, 5,486 miles of primary distribution lines, 86 distribution substations and 10 industrial substations. The 6,162 miles of total sub-transmission and distribution lines include 659 miles of underground lines. Although approximately 57% of the District's electric energy sales are to commercial and industrial customers, the District's electric system is primarily a rural distribution system.