16 Pa. C.S. § 13705
The sheriff of each county may appoint deputies and clerks to positions established in accordance with section 14723 (relating to number and compensation of officers, deputies, assistants, clerks and employees and revisions of salary schedules) for the transaction of the business of the sheriff's office. The sheriff may revoke the appointment of deputies in the same manner as the chief deputy. In counties of the third, fourth, fifth, sixth, seventh and eighth class, the sheriff may also appoint as necessary special deputies to assist the sheriff in executing a civil or criminal process or court order or in preserving the peace when an emergency arises. A special deputy shall serve for a period only as necessary to conduct the special deputy's duties under this section.
16 Pa.C.S. § 13705