The supervising electrician shall not be less than 21 years of age, and shall have had at least two years experience in the installation, alteration, repair, and maintenance of electrical wires, equipment and apparatus, or an experience equivalent thereto. Applicants shall furnish the names and addresses of former employers, period of time employed, and in what capacity, proof of which service shall be furnished in a manner satisfactory to the Chief Electrical Inspector, or every applicant shall be required to answer a reasonable number of questions in writing, to show that he has sufficient knowledge and technical training to supervise the installation, alteration, repair, and maintenance of electrical wires and apparatus authorized by permits issued by the Electrical Department. Applicants shall be required to answer to the satisfaction of the Chief Electrical Inspector at least 70% of the questions prepared by the Chief Electrical Inspector.
('69 Code, § 8-52)