S.C. Code Ann. § 33-49-430: Quorum.

Five percent of all members present in person shall constitute a quorum for the transaction of business at all meetings of the members unless the bylaws prescribe the presence of a greater percentage of the members for a quorum. If less than a quorum is present at any meeting a majority of those present in person may adjourn the meeting from time to time without further notice. A vote cast by a member at an early voting site counts for purposes of determining the presence of a quorum at the meeting where the election is to be held. Voting by proxy for any purpose is prohibited.