Nothing in this subtitle shall be construed to prevent any person from doing or performing the kinds of work of master, master restricted, or maintenance electrician, as herein defined, provided that such work is performed under the direction and supervision of a duly licensed master or maintenance electrician; but no such work shall be performed excepting under such direction and supervision of a duly licensed master or maintenance electrician, and the said licensed electrician shall be responsible for any and all work so done under his direction and supervision. The provisions of this subtitle shall not apply:to journeymen electricians or apprentices while such journeymen or apprentices are practicing their trade of journeymen electrician or apprentice; nor to any public service companies subject to regulation by the Public Service Commission. City Code, 1976/83, art. 13, §80(a), (c) Ord. 83-931