In any county having a civil service system for the sheriff's department pursuant to chapter 8, part 4 of this title or other general law or a private act, or a civil service system for all county employees pursuant to a private act, the employment or termination of employment of any deputy or assistant in any offices covered by this chapter shall be pursuant to such civil service system, and § 8-20-109 shall not apply to such county.
T.C.A. § 8-20-112