5 CFR § 340.202 - General.
(a) Definitions. Part-time career employment means regularly scheduled work of from 16 to 32 hours per week performed by an employee of an agency as defined in 5 U.S.C. 3401 (a) through (f), who has an appointment in tenure group I or II and who becomes employed on such part-time basis on or after April 8, 1979.
Tenure group I applies to employees in the competitive service under career appointments who are not serving probation and permanent employees in the excepted service whose appointments carry no restrictions or conditions.
Tenure group II applies to employees in the competitive service serving probation, career-conditional employees, and career employees in obligated positions. It also includes employees in the excepted service serving trial periods, whose tenure is indefinite solely because they occupy obligated positions; or whose tenure is equivalent to career-conditional in the competitive service.
(b) Agency Exceptions. As an exception to the general definition of part-time employment in § 340.202(a) and under the authority provided in 5 U.S.C. 3402(a)(3), an agency may permit an employee who has an appointment in tenure group I or II to perform regularly scheduled work of from 1 to 15 hours per week.
(c) Mixed Tours of Duty. The provisions of this subpart and the term “part-time career employment” do not apply to employees with appointments in tenure groups I or II who work under mixed tours of duty. For this purpose, a mixed tour of duty consists of annually recurring periods of full-time, part-time, or intermittent service as long as the employee does not work part-time more than 6 pay periods per calendar year.