5 C.F.R. § 6.2
OPM shall list positions that it excepts from the competitive service in Schedules A, B, C, and D, and it shall list the position of administrative law judge in Schedule E, which schedules shall constitute parts of this rule, as follows:
Schedule A. Positions other than those of a confidential or policy-determining character for which it is not practicable to examine shall be listed in Schedule A.
Schedule B. Positions other than those of a confidential or policy-determining character for which it is not practicable to hold a competitive examination shall be listed in Schedule B. Appointments to these positions shall be subject to such noncompetitive examination as may be prescribed by OPM.
Schedule C. Positions of a confidential or policy-determining character shall be listed in Schedule C.
Schedule D. Positions other than those of a confidential or policy-determining character for which the competitive service requirements make impracticable the adequate recruitment of sufficient numbers of students attending qualifying educational institutions or individuals who have recently completed qualifying educational programs shall be listed in Schedule D. These positions are temporarily placed in the excepted service to enable more effective recruitment from all segments of society by using means of recruiting and assessing candidates that diverge from the rules generally applicable to the competitive service.
Schedule E. Positions of administrative law judge appointed under 5 U.S.C. 3105 shall be listed in Schedule E. Conditions of good administration warrant placing the position of administrative law judge in the excepted service and exempting appointment to this position from the requirements of 5 CFR, part 302 , including examination and rating requirements, though each agency shall follow the principle of veteran preference as far as administratively feasible.
5 C.F.R. §6.2