(a) Circuit breakers or other overload devices shall be provided to protect power circuits.
(b) Insulating platforms of dry wood, rubber, or other suitable nonconductive material shall be kept in place at each switchboard, underground telephone station, power control switches, and at stationary machinery where shock hazards exist; provided, that metal plates on which a person normally would stand and which are kept at the same potential as the grounded, metal noncurrent-carrying parts of the power switches to be operated may be used.