(1) Subject to subsection (3), all parts of machinery liable to cause injury shall be effectively guarded with guards of sound construction, properly maintained and kept in position whenever the parts required to be guarded are in motion or in use at any speed and for any purpose.
(2) Subject to subsection (3), whenever practicable, guards on power driven machines shall be interlocked with machine controls so as to prevent operation of the machines unless the guards are properly in position.
(3) The provisions of subsections (1) and (2) shall not apply where a part of machinery covered therein is necessarily exposed for examination or for any testing, lubrication or adjustment shown by the examination to be necessary and the examination, testing, lubrication or adjustment can only be carried out while the part is in motion.