No member of the General Assembly or any member of a member's law firm shall appear before the commission in any rate-fixing proceeding by representing any party in the proceeding for any purposes including political purposes, and it is the duty of the presiding commissioner or hearing officer to enforce the provisions of this section. However, this section does not apply to any member of the General Assembly appearing as a witness on either side of any hearing.
S.C. Code § 58-3-142