All apprentices as herein defined shall be registered with the City-County Electrical Examining and Appeals Board. No fee shall be required for such registration and no test shall be required for such registration. The City-County Electrical Examining and Appeals Board, upon acceptance of such registration, shall issue a Certificate of Registration to each registrant. Such registration shall authorize such apprentice to do electrical work, provided such work is done under the direct personal supervision of a licensed journeyman at all times. Such supervision shall be defined as the doing of work within sight and audible communication with a journeyman electrician. No work shall be done by an apprentice when not in the presence of and under the supervision of a journeyman. No more than three apprentices shall perform electrical work at the same time under the supervision of one journeyman electrician. All apprentice registrations and certificates shall expire on the 31st day of December of the year in which they are issued.