S.C. Code § 58-27-1000
All charges for electricity for light, heat or power established by any franchise granted to or contract made prior to March 24, 1922 with any person or corporation by any municipality pursuant to and under the authority of the laws of this State are to be deemed excepted from the regulatory powers of the Commission and to be unaffected by the provisions of this chapter. All charges established by any franchise or municipal contract subsequent to March 24, 1922 shall be subject to the regulatory powers of the Commission and may be changed by it for proper cause under the provisions of this chapter. It is the purpose of this chapter to regulate such charges only to the extent that it may be done consistently with the Constitutions of this State and of the United States.
S.C. Code § 58-27-1000