5 CFR § 317.601 - Authorization.
(a) An agency may make a noncareer or limited appointment only to a general position.
(b) Each use of a noncareer appointment authority must be approved individually by the Office of Personnel Management, and the authority reverts to the Office upon departure of the incumbent, unless otherwise provided by the Office.
(c) Use of a limited appointment authority is subject to the conditions in this paragraph.
(1) Agencies are provided a pool of limited appointment authorities equal to 3 percent of their Senior Executive Service (SES) position allocation, or one authority, whichever is greater. An agency may use the pool to make a limited appointment only of an individual who has a career or career-conditional appointment (or an appointment of equivalent tenure) in a permanent civil service position outside the SES. If necessary, the Office of Personnel Management may suspend use of the pool authority.
(2) Each use of a limited appointment authority other than under paragraph (c)(1) of this section must be approved individually by the Office, and the authority reverts to the Office upon departure of the incumbent, unless otherwise provided by the Office.