Tenn. Code Ann. § 8-8-402: Local approval required

(a) Except as provided in subsection (b), this part shall be local in effect and shall become effective in a particular county upon the contingency of a two-thirds (2/3) vote of the county legislative body approving this law.

(b) On or after June 9, 2010, § 8-8-419(a)(2) shall apply in any particular county which has adopted or which after June 9, 2010, makes this part applicable to such county, and shall also apply in any other county, notwithstanding any private act, resolution, personnel policy or charter provision to the contrary, which has adopted or which adopts a sheriff's civil service law.