21. Fencing of machinery . - (1) In every factory the following, namely, - (i) every moving part of a prime mover and every flywheel connected to a prime mover, whether the prime mover or flywheel is in the engine house or not; (ii) the headrace and tailrace of every water-wheel and water turbine; (iii) any part of a stock-bar which projects beyond the head stock of a lathe; and (iv) unless they are in such position or of such construction as to be safe to every person employed in the factory as they would be if they were securely fenced, the following, namely – (a) every part of an electric generator, a motor or rotary converter; (b) every part of transmission machinery; and (c) every dangerous part of any other machinery, shall be securely fenced by safeguards of substantial construction which shall be constantly maintained and kept in position while the parts of machinery they are fencing are in motion or in use : Provided that for the purpose of determining whether any part of machinery is in such position or is of such construction as to be safe as aforesaid, account shall not be taken of any occasion when – (i) it is necessary to make an examination of any part of the machinery aforesaid while it is in motion or, as a result of such examination, to carry out lubrication or other adjusting operation while the machinery is in motion, being an examination or operation which it is necessary to be carried out while that part of the machinery is in motion, or (ii) in the case of any part of a transmission machinery used in such process as may be prescribed (being a process of a continuous nature the carrying on of which shall be, or is likely to be, substantially interfered with by the stoppage of that part of the machinery), it is necessary to make an examination of such part of the machinery while it is in motion or, as a result of such examination, to carry out any mounting or shipping of belts or lubrication or other adjusting operation while the machinery is in motion, and such examination or operation is made or carried out in accordance with the provisions of sub-section (1) of section 22. (2) The State Government may by rules prescribe such further precautions as it may consider necessary in respect of any particular machinery or part thereof, or exempt, subject to such condition as may be prescribed, for securing the safety of the workers, any particular machinery or part thereof from the provisions of this section. | 
