May 21.]

"Earthed" means connected to the general mass of earth
in such manner as will ensure at all times an immediate dis-
charge of electrical energy without danger.
"Earthing system" means an electrical system in which
all the conductors are earthed.
"Switch gear" means switches or fuses, conductors, and
other apparatus in connection therewith used for the pur-
pose of controlling the current or pressure in any system or
part of a system.
"Authorized person" means a person appointed in writing
by the manager of the mine to carry out certain duties in-
cidental to the generation, transformation, distribution, or
use of electrical energy in the mine, such person being a per-
son who is competent for the purposes of the rule in which
the term is used.
"Electrician" means a person appointed in writing by the
manager of the mine to supervise the apparatus in the mine
and the working thereof, such person being a person who is
over twenty-one years of age and is competent for the pur-
poses of the rule in which the term is used.
"Danger" means danger to health or danger to life or
limb from shock, burn, or other injury to persons employed,
or from fire explosion attendant upon the generation, trans-
formation, distribution, or use of electrical energy.
"Use" of electricity means the conversion of electricity
into mechanical energy, heat, or light for the purpose of
providing mechanical energy, heat, or light.

251. Electricity shall not be used in any part of a mine
     where, on account of the risk of explosion of gas or coaldust,
     the use of electricity would be dangerous to life; and if the
     owner of a mine, on being required by an Inspector not to
     use, or to desist from using, electricity in the mine or any
     part thereof on such ground as aforesaid, refuses to do so,
     the question as to the application of this regulation to the
     mine or any part thereof shall be settled by the Chief In-
     spector.

252. If at any time at any place in the mine the percentage
     of inflammable gas in the general body of the air in that place
     is found to exceed 11, the electric current shall at once be
     cut off from all cables and other electrical apparatus in that
     place, and shall not be switched on again as long as the
     percentage of inflammable gas exceeds that amount:

Provided that nothing in this regulation shall apply to
any telephone or signalling wires or instruments, as long as
the conditions prescribed with reference to the installation
and use of such wires and instruments are complied with,
nor to any electric hand-lamps for the time being ap-
proved.

253. Notices shall be sent to the Inspector on forms pre-
     scribed by the Minister, as follows, namely,
     (a.) Notice of the intention to introduce apparatus into
     any mine or into any ventilating district in any
     mine.
     (b.) Notice of the intention to introduce or reintroduce
     electricity into any mine where the use of electricity
     has previously been prohibited.
     (c.) On or before the 21st day of January in every year,
     an annual return giving the size and type of appa-
     ratus, and any particulars which may be required
     by the Minister as to the circumstances of its use.

If the Inspector does not object in writing, within one
calendar month from the receipt by him of the notice, to the
carrying-out of either of the intentions specified in the first
or second notices, the owner shall be entitled to carry out such
intention or intentions:

Providing that this regulation shall not apply to telephones
and signalling-apparatus.

254. A proper plan on the same scale as that kept at the
     mine in fulfilment of the requirements of the said Act shall be
     kept in the office at the mine, showing the position of all
     fixed apparatus in the mine other than cables, telephones,
     and signalling-apparatus. The said plan shall be corrected
     as often as may be necessary to keep it reasonably up to date,
     and it shall be produced to an Inspector of Mines at any time
     on his request.

255. The following notices, constructed of durable material,
     shall be exhibited where necessary:-
     (a.) A notice prohibiting any person other than an authorized
     person from handling or interfering with apparatus.
     (b.) A notice containing directions as to procedure in case
     of fire. This notice shall be exhibited in every place
     containing apparatus other than cables, telephones,
     and signalling-apparatus.
     (c.) A notice containing directions as to the restoration of
     persons suffering from the effects of electric shock.
     (d.) A notice containing instructions how to communicate
     with the person appointed in charge of the switch
     gear, as provided by Regulation 263 (1) hereof.
     This notice shall be exhibited at the shaft-bottom.

256. In all places lighted by electricity, where a failure
     of the electric light would be likely to cause danger, one or
     more safety-lamps or other proper lights shall be kept con-
     tinuously burning.

257. Fire-buckets of suitable capacity, filled with clean
     dry sand ready for immediate use in extinguishing fires,
     shall be kept in every place containing apparatus other than
     cables, telephones, and signalling-apparatus.

258. (1.) Where necessary to prevent danger or mechanical
     damage, transformers and switch gear shall be placed in a
     separate room, compartment, or box.

(2.) Unless the apparatus is so constructed, protected, and
worked as to obviate the risk of fire, no inflammable material
shall be used in the construction of any room, compartment,
or box containing apparatus, or in the construction of any of
the fittings therein. Each such room, compartment, or box
shall be substantially constructed, and shall be kept dry.

(3.) Adequate working-space and means of access clear
of obstruction and free from danger shall be provided for all
apparatus that has to be worked or attended to by any person,
and all handles intended to be operated shall be conveniently
placed for that purpose.

259. (1.) All apparatus and conductors shall be sufficient
     in size and power for the work they may be called upon to do,
     and so constructed, installed, protected, worked, and main-
     tained as to prevent danger so far as is reasonably practicable.

(2.) All insulating-material shall be chosen with special
regard to the circumstances of its proposed use. It shall
be of mechanical strength sufficient for its purpose, and so
far as is practicable it shall be of such a character, or so
protected, as fully to maintain its insulating properties under
working-conditions of temperature and moisture.

(3.) Every part of a system shall be kept efficiently in-
sulated from earth, except that (a) the neutral point of a
polychase system may be earthed at one point only; (b) the
mid-voltage point of any system, other than a concentric
system, may be earthed at one point only; and (c) the outer
conductor of a concentric system shall be earthed. Where
any point of a system is earthed it shall be earthed by con-
nection to an earthing-system at the surface of the mine.

(4.) Efficient means shall be provided for indicating any
defect in the insulation of a system.

260. (1.) All metallic sheaths, coverings, handles, joint-
     boxes, switch-gear frames, instrument-covers, switch and
     fuse covers and boxes, and all lampholders unless efficiently
     protected by an earthed or insulating covering made of
     fire-resisting material, and the frames and bed-plates of
     generators, transformers, and motors (including portable
     motors) shall be earthed by connection to an earthing-system
     at the surface of the mine.

(2.) Where the cables are provided with a metallic cover-
ing constructed and installed in accordance with Regula-
tion 264 (c) such metallic covering may be used as a means
of connection to the earthing-system. All the conductors
to an earthing-system shall have a conductivity at all parts
and at all joints at least equal to 50 per cent. of that of the
largest conductor used solely to supply the apparatus, a part
of which it is desired to earth: Provided that no conductor
of an earthing-system shall have a cross-sectional area of less
than 0·022 square inch.

(3.) All joints in earth conductors, and all joints to the
metallic covering of the cables, shall be properly soldered
or otherwise efficiently made, and every earth conductor
shall be soldered into a lug for each of its terminal connec-
tions. No switch, fuse, or circuit-breaker shall be placed
in any earth conductor.

This regulation shall not apply (except in the case of portable
apparatus) to any system in which the pressure does not
exceed low-pressure direct current or 125 volts alternating
current.

261. (1.) Where electricity is distributed at a pressure
     higher than medium pressure (a) it shall not be used without
     transformation to medium or low pressure except in fixed
     machines in which the high or extra-high pressure parts
     are stationary; and (b) motors under 20 horse-power shall
     be supplied with current through a transformer stepping
     down to medium or low pressure.

(2.) Where energy is transformed, suitable provision shall
be made to guard against danger by reason of the lower-
pressure apparatus becoming accidentally charged above
its normal pressure by leakage from or contact with the
higher-pressure apparatus.

262. Switch gear and all terminals, cable-ends, cable-
     joints, and connections of apparatus shall be constructed
     and installed so that—

(a.) All parts shall be of mechanical strength sufficient to
resist rough usage.

(b.) All conductors and contact areas shall be of ample
current-carrying capacity, and all joints in con-
ductors shall be properly soldered or otherwise
efficiently made.