S.C. Code Ann. § 7-13-1430

In counties where marking devices and automatic tabulating equipment have been adopted, the county board of voter registration and elections shall establish one or more counting stations to receive voted ballots and other precinct election supplies after the polling precincts are closed. Such stations shall be under the supervision and direction of the board of voter registration and elections. Processing and counting of voted ballots and the preparation of summary sheets shall be done in the presence of witnesses approved by the board of voter registration and elections.