S.C. Code Ann. § 4-7-120

The commissioners of election, respectively, shall, as judicial officers, decide all cases of protest or contest that may arise, subject to appeal to the Board of State Canvassers. The decision of the commissioners of election shall be final and conclusive evidence of the result of the election, unless appealed from within five days, in which case a decision of the Board of State Canvassers shall be final and conclusive evidence of the election on all questions of fact.