(1) Subject to the following provisions of this regulation and to the provisions of the Coal and Other Mines (Electricity) Regulations, 1956 , electric lights supplied with electricity from a source of electric power external to the lighting unit are hereby authorised to be used at the following places in mines in which the use of lamps or lights, other than permitted lights, is unlawful (either throughout or in any part) that is to say—
(a) in any length of road ventilated by air none of which has ventilated a working face except within one hundred and fifty feet of a working face accessible from that length of road;
(b) in any length of any other road except within nine hundred feet of a working face accessible from that length of road;
(c) where electric power is used at a working face, in any length of road which is an intake airway as regards that face except within thirty feet of a face and in any other length of road used in connection with that face except within three hundred feet of that face;
(d) if authorised by a notice served by an inspector on the manager, in any length of road described in the notice except within thirty feet of a working face;
and accordingly such electric lights so used are permitted lights in those mines.
(2) Where electric lights are installed at any place by virtue of sub-paragraph (c) of the last preceding paragraph, the manager shall forthwith give notice thereof to the inspector for the district.
(3) Electricity at a voltage exceeding two hundred and fifty shall not be applied to any such lights and if the system is polyphase the neutral point shall be connected to earth or if it is not polyphase the mid-voltage point shall be connected to earth:
Provided that the provisions of this paragraph shall not apply to any system of electric lighting by direct current installed in a seam in a mine before the first day of August, nineteen hundred and forty-seven.
(4) It shall be the duty of the manager to ensure that appropriate precautions are taken to prevent damage to any such electric lighting system from shot firing and that every lamp fitting is so constructed as to protect the lamp from accidental damage.
(5) In any part of a mine in which inflammable gas, although not normally present, is likely to occur in a quantity sufficient to indicate danger, no electrical apparatus, other than apparatus of a type approved by the Minister, shall be used as part of such a system in any length of road within nine hundred feet of a working face accessible from that road.