Tennessee Code Title 8. Public Officers and Employees § 8-35-103

(a) Any person who becomes a part-time employee or who is currently serving as a part-time employee on July 1, 1984, may elect to join the Tennessee consolidated retirement system. The election shall be made in the manner prescribed by the retirement system and shall be filed with the retirement system; provided, that the following employees shall not be eligible for membership:

(b) The employee's date of membership shall be the date the election is filed with the retirement system and shall be used to determine all rights and benefits under chapters 34-37 of this title.

(c) Part-time employees working in institutions of higher education shall be eligible for membership in the optional retirement plan found in chapter 25, part 2 of this title if it is certified by the institution that the employee is a teacher.

(d) In cases of doubt as to the classification of an employee, the board of trustees shall determine from objective criteria whether an employee is properly classified.

(e) Any retiree-beneficiary who accepts part-time employment with an employer participating in this system will be considered as restored to employment within the meaning of chapter 36, part 8 of this title, regardless of whether such retiree-beneficiary is eligible for membership.