N.C. Gen. Stat. § 153A-26
Each person elected by the people or appointed to a county office shall, before entering upon the duties of the office, take and subscribe the oath of office prescribed in Article VI, Sec. 7 of the Constitution. The oath of office shall be administered by some person authorized by law to administer oaths and shall be filed with the clerk to the board of commissioners.
On the first Monday in December following each general election at which county officers are elected, the persons who have been elected to county office in that election shall assemble at the regular meeting place of the board of commissioners. At that time each such officer shall take and subscribe the oath of office. An officer not present at this time may take and subscribe the oath at a later time.
N.C. Gen. Stat. § 153A-26