S.C. Code § 58-31-440
Lines of the Public Service Authority in existence on July 1, 1984, which extend into the service areas of Berkeley Electric Cooperative, Santee Electric Cooperative, and Horry Electric Cooperative, and lines of those cooperatives which extend into the service area of the Public Service Authority may continue to be operated and maintained by the owner of the lines, and premises served by the lines on July 1, 1984, must continue to be so served. The owner of a line in another supplier's service area may exclusively serve any new premises located wholly or partially within three hundred feet of the line. Where the premises are located wholly or partially within three hundred feet of a line of both the Public Service Authority and an electric Cooperative, the customer may choose between those suppliers, and the supplier originally chosen shall continue to have the exclusive right to serve such premises.
S.C. Code § 58-31-440