(1) An employee who has had less than six (6) calendar months of service on the date his department commences participation in the personnel system shall be required to pass a suitable noncompetitive examination and satisfactorily complete a probationary period in order to be retained in a position.
(2) An employee who does not obtain a passing grade in the examination referred to in subsection (2) [(1)] of this section shall be separated from his position within thirty (30) days after the establishment of an adequate register of eligibles for such position.