Code of Federal Regulations Title 5. Administrative Personnel § 5.575.304 Ineligible categories of employees

(1) To which an individual is appointed by the President without the advice and consent of the Senate, except a Senior Executive Service position in which the individual serves as a career appointee (as defined in 5 U.S.C. 3132(a)(4));

(2) Designated as the head of an agency, including an agency headed by a collegial body composed of two or more individual members;

(3) In which the employee is expected to receive an appointment as the head of an agency;  or

(4) To which an individual is appointed as a Senior Executive Service limited term appointee or limited emergency appointee (as defined in 5 U.S.C. 3132(a)(5) and (a)(6), respectively) when the appointment must be cleared through the White House Office of Presidential Personnel.