N.C. Gen. Stat. § 163-106.1: Eligibility to file.

No person shall be permitted to file as a candidate in a party primary unless that person has been affiliated with that party for at least 90 days as of the date of that person filing such notice of candidacy. A person registered as "unaffiliated" shall be ineligible to file as a candidate in a party primary election. (1915, c. 101, ss. 6, 15; 1917, c. 218; C.S., ss. 6022, 6035; 1921, c. 217; 1923, c. 111, s. 13; C.S., s. 6055(a); 1927, c. 260, s. 19; 1929, c. 26, s. 1; 1933, c. 165, s. 12; 1937, c. 364; 1947, c. 505, s. 7; 1949, c. 672, s. 4; c. 932; 1951, c. 1009, s. 3; 1955, c. 755; c. 871, s. 1; 1959, c. 1203, s. 4; 1965, c. 262; 1967, c. 775, s. 1; c. 1063, s. 2; 1969, c. 44, s. 83; c. 1190, s. 56; 1971, cc. 189, 675, 798; 1973, c. 47, s. 2; c. 793, s. 36; c. 862; 1975, c. 844, s. 2; 1977, c. 265, ss. 4, 5; c. 408, s. 2; c. 661, ss. 2, 3; 1979, c. 24; c. 411, s. 5; 1981, c. 32, ss. 1, 2; 1983, c. 330, s. 1; 1985, c. 472, s. 2; c. 558, s. 1; c. 759, s. 6; 1985 (Reg. Sess., 1986), c. 957, s. 1; 1987, c. 509, s. 13; c. 738, s. 124; 1987 (Reg. Sess., 1988), c. 1028, s. 1; 1993 (Reg. Sess., 1994), c. 762, s. 31; 1995, c. 243, s. 1; 1996, 2nd Ex. Sess., c. 9, s. 8; 1999-456, s. 59; 2001-403, s. 3; 2001-466, s. 5.1(a); 2002-158, ss. 8, 9; 2002-159, s. 55(a); 2006-155, s. 2; 2007-369, s. 1; 2009-47, s. 1; 2013-381, s. 21.1; 2014-111, s. 1(a); 2016-125, 4th Ex. Sess., s. 21(a); 2017-3, s. 5; 2017-6, s. 3; 2018-146, s. 3.1(a), (b).)