In addition to the education and experience requirements imposed in the State Electrical Act and except as otherwise provided in section 81-2116, each applicant shall, prior to issuance of a license under the act, pass a written examination given by the board to insure his or her competence. Such examination shall contain reasonable questions based upon the then current National Electrical Code and upon electrical theory. When answering questions based upon the National Electrical Code, the applicant may refer to an open copy of such code. Examinations shall be given at least twice yearly. Any licensee failing to renew his or her license by April 1 after its expiration shall take the examination before he or she is issued a new license.