5 C.F.R. § 430.202 – Coverage.

(a) Employees and agencies covered by statute.
1. (1) Section 4301(1) of title 5, United States Code, defines agencies covered by this subpart.
2. (2) Section 4301(2) of title 5, United States Code, defines employees covered by statute by this subpart. Besides General Schedule (GS/GM) and prevailing rate employees, coverage includes, but is not limited to, senior-level and scientific and professional employees paid under 5 U.S.C. 5376.
(b) Statutory exclusions. This subpart does not apply to agencies or employees excluded by 5 U.S.C. 4301(1) and (2), the United States Postal Service, or the Postal Rate Commission.
(c) Administrative exclusions. OPM may exclude any position or group of positions in the excepted service under the authority of 5 U.S.C. 4301(2)(G). The regulations in this subpart exclude excepted service positions for which employment is not reasonably expected to exceed the minimum period established under § 430.207(a) in a consecutive 12-month period.
(d) Agency requests for exclusions. Heads of agencies or their designees may request the Director of OPM to exclude positions in the excepted service. The request must be in writing, explaining why the exclusion would be in the interest of good administration.