73. Supply to X-ray and high frequency installation .-(1) Any person who proposes to employ or who is employing energy for the purpose of operating an X-ray or similar high-frequency installation, shall comply with the following conditions:-
(a)Mechanical barriers shall be provided to prevent too close an approach to any high voltage parts of the X-ray apparatus, except the X-ray tube and its leads, unless such high voltage parts have been rendered shock-proof by being shielded by earthed metal or adequate insulating material.(b)Where extra-high voltage generators operating at 300 peak KV or more are used, such generators shall be installed in rooms separate from those containing the other equipment and any step-up transformer employed shall be so installed and protected as to prevent danger.(c)A suitable switch shall be provided to control the circuit supplying a generator, and shall be so arranged as to be open except while the door of the room housing the generator is locked from the outside.(d)X-ray tubes used in therapy shall be mounted in an earthed metal enclosure.(e)Every X-ray machine shall be provided with a milliammeter or other suitable measuring instrument, readily visible from the control position and connected, if practicable, in the earthed lead, but guarded if connected in the high voltage lead.(ee)[ Notwithstanding the provisions of clause (e) an earth leakage circuit breaker of sufficient rating shall be provided on the low voltage side to detect the leakage in such X-ray installations.](f)This sub-rule shall not apply to shock-proof portable units or shock-proof self-contained and stationary units.Note .-The expression "shock-proof" as applied to X-ray and high frequency equipment shall mean that such equipment is guarded with earthed metal so that no person may come into contact with any live part.(2)(a)In the case of non-shock-proof equipment, overhead high voltage conductors, unless suitably guarded against personal contact, shall be adequately spaced and high voltage leads on tilting-tables and fluroscopes shall be adequately insulated or so surrounded by barriers as to prevent inadvertent contact.(b)The low voltage circuit of the step up transformer shall contain a manually operated control device having overload protection in addition to the over-current device for circuit protection, and these devices shall have no exposed live parts and for diagnostic work there shall be an additional switch in the said circuit, which shall be of one of the following types:-(i)a switch with a spring or other mechanism that will open automatically except while held close by the operator, or(ii)a time switch which will open automatically after a definite period of time for which it has been set.(c)If more than one piece of apparatus be operated from the same high or extra-high voltage source each shall be provided with a high or extra-high voltage switch to give independent control.(d)Low frequency current-carrying parts of a machine of the quenched-gap or open gap type shall be so insulated or guarded that they cannot be touched during operation, the high frequency circuit proper which delivers high-frequency current normally for the therapeutic purposes, being exempted.(e)All X-ray generators having capacitors shall have suitable means for discharging the capacitors manually.(f)Except in the case of self-contained units, all 200 peak KV or higher, X-ray generators shall have a sphere gap installed in the high voltage system adjusted so that it will break down on over-voltage surges.(3)(a)All non-current carrying metal parts of tube stands, fluroscopes and other apparatus shall be properly earthed and insulating floors, mats or platforms shall be provided for operators in proximity to high or extra-high voltage parts unless such parts have been rendered shock proof.(b)Where short wave therapy machines are used, the treatment tables and examining chairs shall be wholly non-metallic.(4)The owner of any X-ray installation or similar high frequency apparatus shall not bring the same into use without giving to the Inspector not less than 14 days' notice in writing of his intention to do so:Provided that the aforesaid notice shall not be necessary in the case of shock-proof portable X-ray and high-frequency equipment which have been inspected before the commencement of their use and periodically, thereafter.
