Md. Code, Public Utilities § 18–107

(a) The Commission may establish a merit system that includes all of its employees except:

(1) the general manager, secretary, treasurer, and chief engineer;

(2) the head of a department;

(3) (i) the inspector general; and

(ii) any temporary employee of the Office of the Inspector General appointed under § 17–603 of this article; and

(4) a part time, temporary, or contract employee.

(b) The Commission may:

(1) appoint or promote a merit system employee to the position of general manager, department head, or inspector general or designate a merit system employee as the general manager, department head, or inspector general on an acting basis;

(2) retain the employee in the merit system in the position or grade from which the employee was appointed or promoted; and

(3) continue to exclude the positions of general manager, department head, and inspector general from the merit system.