S.C. Code § 58-27-410
All cities and towns of the State may grant the exclusive franchise of furnishing light to such cities and towns and the inhabitants thereof. But no such franchise shall be valid unless it shall first receive the vote of two thirds of the board of aldermen or common council of the city or town granting it and be subsequently confirmed by a vote of the majority of the qualified electors of the city or town, voting at an election called specially for the purpose. The ordinance or resolution granting such a franchise shall fix a maximum rate for furnishing light, both for public and private consumption and the person obtaining such exclusive franchise shall have no power to charge or receive any greater price for light thus furnished than the maximum rate so fixed. No such franchise shall affect any existing contractual rights.
S.C. Code § 58-27-410