40 ILCS 5/8-193
In each year, the board shall conduct a regular election, under rules adopted by it, at least 30 days prior to the expiration of the term of the employee member whose term next expires, for the election of a successor for a term of 3 years. Each employee member and his successor shall be an employee who holds a position by certification and appointment as a result of a competitive civil service examination as distinguished from temporary appointment for a period of not less than 5 years prior to the date of election or so holds a position which is not exempt from the classified or the personnel ordinance by a city that adopted a career service ordinance. At any such election including the initial election and special elections to fill vacancies in such office, all persons who are employee participants at the time such election is held, shall have a right to vote. The ballot shall be of secret character.
Any elective member of the board shall hold office until his successor is elected and qualified.
Any person elected or appointed as a member of the board shall qualify by taking an oath of office to be administered by the city clerk. A copy thereof shall be kept in the office of the city clerk.
40 ILCS 5/8-193