31. This act shall not apply:
(a) to mines or to ore processing plants governed by the Mining Act (chapter M-13);
(b) to telephone or telegraph companies in the exercise of their functions as such; to electricity distributors and to railway companies using electrical traction; or to wiring in railway rolling stock;
(c) to aviation and marine work done on the machines themselves;
(d) to any stationary engineer holding a first or second class diploma, for the performance of improvement or repair work on motors and dynamos in the establishment where he is regularly employed;
(e) to work in electrical stations or their branches used for generating, transforming or distributing electric power, either by a public service corporation or by a municipal department or by an electricity co-operative governed by the Rural Electrification Board, when the work is done by their employees under the control and direction of officers of such corporation, such municipal service, or of the co-operative;
(f) to owners of public buildings within the meaning of the Electricians and Electrical Installations Act for work of restoration, alteration or repair in their buildings contemplated by an annual permit issued under the said act, and carried out by a holder of licence A-2 or under his supervision.