S.C. Code Ann. § 33-10-210: Bylaw increasing quorum or voting requirement for shareholders.

(a) If authorized by the articles of incorporation, the shareholders may adopt or amend a bylaw that fixes a greater quorum or voting requirement for shareholders (or voting groups of shareholders) than is required by Chapters 1 thru 20 of this title. The adoption or amendment of a bylaw that adds, changes, or deletes a greater quorum or voting requirement for shareholders must meet the same quorum requirement and be adopted by the same vote and voting groups required to take action under the quorum and voting requirement then in effect or proposed to be adopted, whichever is greater.

(b) A bylaw that fixes a greater quorum or voting requirement for shareholders under subsection (a) may not be adopted, amended, or repealed by the board of directors.