The principal connection, however, was a new 220 kV single-circuit overhead transmission line built using lattice steel towers from Roxburgh to a new substation at Islington on the outskirts of Christchurch. By 1949 the surveys for this line were well under way with by 1951 the construction camps established and the material on order. By 1954 the first section of the line had been completed, which allowed it to carry power from Tekapo A to Christchurch. A second section as far south as the Waitaki Valley helped improve supply conditions during winter. The Roxburgh-Islington line cost approximately £1,000,000 and was completed by the winter of 1956.