S.C. Code § 7-17-30
The county boards shall decide all cases under protest or contest that arise in their respective counties in the case of county officers and less than county offices, except for primaries and municipal elections. Any protest or contest must be filed in writing with the chairman of the board, together with a copy for each candidate in the race, by noon Wednesday following the day of the declaration by the board of the result of the election. However, service upon the chairman may be perfected by depositing with the county sheriff one copy of the protest, together with a copy for each candidate in the race. The sheriff must take immediate steps to deliver the copies to the chairman. The protest must contain each ground concisely stated separately. The chairman of the board must serve upon each candidate in the protested race a copy of the protest and serve a notice of the time and place of the meeting of the board for the purposes of hearing the protest.
S.C. Code § 7-17-30