Mines (Electricity) Regulations, 1972.
Statutory Instruments
Source: Statutory Instruments

num: 1
paragraphs: Short title.
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paragraphs: Commencement.
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paragraphs: Interpretation.
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paragraphs: Application.
num: 5
paragraphs: Exemptions.
PART II.
GENERAL SAFETY PROVISIONS.
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paragraphs: Notice of introduction of electricity.
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paragraphs: Plan of electrical apparatus.
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paragraphs: Main switchgear for cutting off electricity.
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paragraphs: Other means for cutting off electricity.
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paragraphs: Cutting off electricity where flammable gas is found.
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paragraphs: Switches, circuit breakers and other control devices.
12 and 13. Switchboards.
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paragraphs: Suitability of electrical apparatus.
15 and 16. Housing of apparatus.
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paragraphs: Joints and connections.
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paragraphs: Cable couplers.
19, 20.
and 21. Earthing.
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paragraphs: Insulation.
23 and 24. Cables.
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paragraphs: Flexible cables.
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paragraphs: Portable apparatus.
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paragraphs: Portable hand lamps.
28,29.
and 30. Telephone and signalling apparatus.
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paragraphs: Protection of electrical apparatus.
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paragraphs: Electric welding apparatus.
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paragraphs: Apparatus for use where flammable gas may occur.
34 and 35. Working on and testing electrical apparatus.
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paragraphs: Fencing of outdoor electrical apparatus.
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paragraphs: Overhead lines.
num: 38
paragraphs: Transformers (23 ; 3/72).
num: 39
paragraphs: Fire fighting appliances.
PART III.
DUTIES OF THE MANAGER AND APPIONTMENT OF ELECTRICIAN
Regulation
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paragraphs: Introduction of scheme.
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paragraphs: Notices.
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paragraphs: Appointment of competent person.
PART IV.
Revocations.
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paragraphs: Revocations.
S.I. No. 51 of 1972.
MINES (ELECTRICITY) REGULATIONS, 1972.
I, JOSEPH BRENNAN, Minister for Labour, in exercise of the powers conferred on me by sections 11 , 18 , 65 (1), 127 and 146 of the Mines and Quarries Act, 1965 (No. 7 of 1965), and the Labour (Transfer of Departmental Administration and Ministerial Functions) Order, 1966 ( S.I. No. 164 of 1966 ), and after due compliance with the provisions of that Act relating to the procedure for making general regulations, hereby make the following regulations:
PART I. PRELIMINARY AND GENERAL.
num: 1
paragraphs: These Regulations may be cited as the Mines (Electricity) Regulations, 1972.
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paragraphs: These Regulations shall come into operation on the 1st day of April, 1972.
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paragraphs: In these Regulations——
"the Act" means the Mines and Quarries Act, 1965 (No. 7 of 1965);
"circuit" means an electrical circuit forming a system or branch of a system;
"circuit-breaker" means a mechanical device, including any fuse, capable of making and breaking a circuit under normal and abnormal on load conditions such as that of short-circuit, and unless otherwise specified, means a circuit-breaker designed to break a current automatically;
"conductor" means an electrical conductor designed to be electrically connected to a system;
"danger" means danger to health or danger to life or limb from shock, burn, or other injury to persons employed, or from fire attendant upon the generation, transformation, distribution or use of electrical energy;
"dead" means at or about earth potential, and disconnected from any live system;
"earthed" means connected to the general mass of earth in such manner as will at all times ensure an immediate discharge of electrical energy without danger;
"electrical apparatus" includes any conductor or electric cable and any part of any machinery, apparatus or appliance, being a part designed for the generation, conversion, storage, transmission or utilisation of electricity;
"flammable" means capable of being easily ignited;
"flexible cable" means an electric cable which is designed to be movable while in use;
"incendive sparking" means, in relation to any electrical apparatus, sparking in such circumstances that flammable gas present in the air outside the apparatus might be ignited directly or indirectly;
"inspector" means an inspector appointed under the Act;
"insulating material" means non-conducting material enclosing, surrounding or supporting a conductor or any part thereof, and which is of such quality and thickness as to prevent danger;
"insulation resistance" means the resistance between two conductors or systems of conductors normally separated by insulation, or, the resistance between any such conductors and earth;
"isolated" means disconnected from the source of electrical energy;
"live" means electrically charged;
"manager" means a manager appointed in accordance with section 13 of the Act;
"metallic covering" in relation to any cable means an iron or steel wire covering or a rigid iron, steel or other hard metal conduit pipe or other suitable conductive metallic sheath;
"Minister" means the Minister for Labour;
"overhead line" means any electric line which is placed above ground and in the open air at the surface;
"portable apparatus" means electrical apparatus which, because of the manner in which it is to be used, requires to be moved while it is working, or which is designed so that it can be moved while it is working and includes hand-held portable apparatus;
"portable hand lamp" means an electric lamp for inspection purposes suitable for carrying in the hand and supplied with electrical energy from a circuit by means of a flexible cable other than a transportable electric lamp used intermittently for illuminating or inspecting work places;
"substation" means any building, enclosure or other structure or any part thereof which is large enough to enable a person to enter the building, structure or part after the electrical apparatus therein is in position and which contains apparatus for transforming or converting electrical energy either to or from a voltage exceeding 650 volts (not being apparatus for transforming or converting electrical energy solely for the operation of switchgear or instruments), and includes the said apparatus, together with any other apparatus for switching, controlling or otherwise regulating electrical energy, therein;
"switchboard" means the collection of switches, fuses or conductors and any other apparatus ancillary thereto which is used to control the current or voltage in a system or part of a system;
"system" means an electrical system in which all the conductors and apparatus are electrically connected to a common source of electromotive force;
"telephone apparatus" includes any apparatus used exclusively for telephoning or signalling or telephoning and signalling and which is supplied with electricity from a battery of primary or secondary cells at a voltage not exceeding 50 volts, or in the case only of a telephone, from magneto generators operated by hand;
"transportable apparatus" means an apparatus which, from the nature of its use, requires to be moved to a new position from time to time between the periods when it is working:
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paragraphs: Subject to Regulation 5 of these Regulations, these Regulations shall apply in relation to every mine.
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paragraphs: (1) These Regulations shall not apply to:
( a ) any electrical apparatus which is neither used nor intended to be used as part of the equipment of a mine, or
( b ) any electrical apparatus which neither forms nor is intended to form part of such equipment, or
( c ) any service line or apparatus on the electrical supply side of the consumer's terminals, or any chamber containing such service lines or apparatus where the supply is given from outside under Electricity Supply Board Regulations; provided that no live part of such line or apparatus is exposed so that it may be touched.
(2) The Minister or an inspector may, by notice served on the owner, exempt any mine from the application in relation thereto of any provision of these Regulations if he is satisfied that the safety of persons employed at the mine will not be prejudiced as a consequence of granting the exemption.
(3) In this regulation "owner" has the meaning assigned to it by Section 4 of the Act.
PART II. GENERAL SAFETY PROVISIONS.
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paragraphs: (1) Electricity shall not be introduced in a mine below ground unless, not less than thirty days previously, the manager has served on an inspector notice of the intention so to do in such form and accompanied by such particulars as may be specified by the Minister.
(2) This regulation shall not apply to—
( a ) the installation of electrical apparatus for the maintenance, repair or replacement of electrical apparatus lawfully installed in any part of a mine, before the commencement of these Regulations, or
( b ) the installation (including installation for maintenance, repair or replacement) of telephone or signalling apparatus, and for the purposes of this regulation no account shall be taken of such apparatus already installed.
num: 7
paragraphs: It shall be the duty of the manager of a mine in which there is installed below ground electrical apparatus, other than telephone or signalling apparatus, to keep at the office at the mine or at such other place as may be approved by an inspector, a plan or plans showing the position of all such electrical apparatus other than portable or transportable apparatus and flexible cables.
num: 8
paragraphs: (1) There shall be provided at the surface at every mine in which electrical apparatus is installed below ground, suitable switchgear for cutting off the supply of electricity to that apparatus.
(2) The manager of every such mine shall make and secure the efficient carrying out of arrangements whereby an authorised person appointed by him for the purpose of operating such switchgear is in attendance at the surface at the mine whenever any cable below ground in the mine is live.
(3) For the purpose of securing the prompt operation of such switchgear, telephonic communication shall be provided when necessary between the surface and one or more convenient places below ground.
(4) Where necessary to prevent danger, suitable means shall be provided at the surface of the mine to protect electrical apparatus installed below ground from abnormal voltage due to atmospheric electricity.
num: 9
paragraphs: (1) There shall be provided in relation to every circuit, other than a circuit comprising solely telephone or signalling apparatus, effective means, suitably located, for automatically cutting off the supply of electricity from that circuit if the current therein should be dangerously excessive.
(2) There shall be provided in relation to every circuit—
( a ) in which alternating current at a voltage exceeding 650 volts is used, or
( b ) which comprises portable or transportable apparatus and in which alternating current at a voltage exceeding 125 volts is used,
effective means for automatically cutting off the supply of electricity from that circuit if the leakage current to earth should exceed fifteen per cent. of the maximum current for which that circuit is designed or five amperes, whichever is the greater.
num: 10
paragraphs: (1) Where any person finds that at any place below ground in a mine an amount of flammable gas is present in the general body of the air at that place exceeding one and a quarter per cent. by volume or sees an indication of gas at that place on the lowered flame of a safety lamp, that person shall—
( a ) forthwith cause the supply of electricity to be cut off from all electrical apparatus at that place, other than a telephone, signalling apparatus or an electric safety-lamp, in case the taking of those measures falls within the scope of his normal duties, and
( b ) in case they are not within such scope, forthwith report the matter to an official of the mine or a person the scope of whose normal duties includes the taking of those measures.
(2) A person to whom the presence of flammable gas is reported in pursuance of paragraph (1) ( b ) of this regulation shall forthwith cause the supply of electricity to be cut off from all electrical apparatus at the relevant place, other than a telephone, signalling apparatus or an electric safety-lamp.
(3) Whenever the supply of electricity has been cut off from electrical apparatus in pursuance of the foregoing provisions of this regulation, no such supply shall be restored to the apparatus until the senior official who is for the time being on duty at the mine, being satisfied that the amount of flammable gas present in the general body of the air at the relevant place does not exceed one and a quarter per cent. by volume, so directs.
num: 11
paragraphs: (1) Every switch, circuit breaker or other control device controlling circuits to be isolated shall be constructed so that it cannot with proper care be left in partial contact and, unless it is otherwise self-evident, shall be clearly marked to indicate the "ON" and "OFF" positions.
(2) Where practicable, switches shall be connected in a circuit so that the blades will not be live when a switch is open and where this is not practicable permanent warnings shall be provided stating that when the switch is in the open position the blades are live.
(3) Every single pole switch shall be inserted in the live conductor only and any switch so inserted and which is connected with earth shall be a linked switch and shall be arranged so that the live conductor circuit is broken simultaneously.
(4) Where practicable, control devices shall be locate or arranged so that they will not close by gravity, and where this is not practicable the devices shall be provided with stops which will prevent closing by gravity.
(5) Every electrical motor shall be controlled by an efficient switch or switches for starting and stopping and placed so as to be easily worked by the person in charge of the motor.
(6) In every place at a mine in which there are machines driven by an electric motor there shall be means at hand for either switching off the motor or stopping the machine in order to prevent danger.
(7) Switches which are not capable of operating under load shall be—
( a ) key interlocked, or
( b ) mechanically interlocked, or
( c ) electrically interlocked, or
( d ) where it is not practicable to comply with sub-paragraph ( a ), ( b ) or ( c ), of this paragraph, clearly and permanently marked to indicate that they are for isolating use only.
num: 12
paragraphs: (1) The general arrangement of switchboards shall be such that—
( a ) the course of every conductor may, where necessary, be readily traced,
( b ) conductors not designed for connection to the same system are kept apart so that they can, where necessary, be readily distinguished,
( c ) all bare conductors are placed or protected so as to prevent danger from any accidental short circuit,
( d ) all bare conductors which could otherwise be touched shall, unless they are located in an area set apart for that purpose, be suitably fenced or enclosed,
( c ) all parts which may have to be adjusted or handled are readily accessible.
( f ) all apparatus requiring handling can, so far as is practicable, be operated from the front of the switchboard,
( g ) all measuring instruments and indicators are, as far as practicable, so placed that they can be observed from the front of the switchboard,
( h ) clear working space of not less than 0·91 metres (3 feet) in width is available at the back of a switchboard having exposed live parts less than 2·13 metres (7 feet) above the floor, and
( i ) a ready means of access is provided to all enclosures which must be entered in order to operate or maintain the switchboard.
num: 13
paragraphs: (1) In every switchboard for the control of voltages exceeding 650 volts—
( a ) every conductor within reach from the working platform or in any switchboard passage-way shall be placed or protected so as to prevent danger,
( b ) the metal cases of all instruments shall be either earthed or completely enclosed with insulating covers, and
( c ) all metal handles of switches and, where necessary to prevent danger, all metal gear for working the switches shall be earthed.
(2) When work has to be done on any switchboard, then, unless the switchboard is arranged so as to secure that the work may be carried out without danger, either—
(i) the switchboard shall first be made dead, or
(ii) if the switchboard is arranged so that the conductors thereof can be made dead in sections, and each such section is separated by permanent or removable divisions or screens from all adjoining sections in which conductors may be live and work on the section may be carried out without danger, the section on which work has to be done shall first be made dead.
num: 14
paragraphs: (1) Electrical apparatus shall not be used unless it is of sufficient power or capacity to avoid dangerous overloading, and without prejudice to the generality of the foregoing, every circuit breaker shall be of adequate breaking capacity to operate safely on the occurrence of a short circuit and shall be of such construction or be so guarded or placed as to prevent danger from over-heating, arcing or the scattering of hot metal or other substance when the circuit breaker comes into operation.
(2) All conductors and electrical apparatus which may at any time be exposed to the weather, or to wet, corrosion, flammable surroundings or explosive atmosphere or which may at any time be used in any process or for any special purpose other than for lighting or power, shall be constructed or protected, and such special precautions shall be taken, so as adequately to prevent danger because of such exposure or use.
(3) All electrical apparatus shall be suitably identified where necessary to prevent danger.
(4) Electrical apparatus other than cables shall display a plate bearing the maker's name together with all ratings, such as horsepower, voltage and current necessary to show that it is suitable for the purpose for which it is used.
(5) All electrical apparatus shall be constructed, installed, maintained, protected and worked so as to prevent danger and where such apparatus is found to be defective in any way it shall be forthwith put in good order or disconnected.
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paragraphs: (1) Electrical apparatus shall be installed so that—
( a ) adequate protection shall be provided against falling objects,
( b ) a clear space of not less than 0·91 metres (3 feet) is provided between the top of electrical apparatus and any ceiling having exposed combustible material, and
( c ) adequate measures are taken to prevent the accumulation of combustible or conducting dust.
(2) All places in which there is electrical apparatus shall be adequately lighted to prevent danger.
num: 16
paragraphs: (1) Every sub-station below ground or in a building at the surface of a mine shall be substantially constructed and shall be—
( a ) arranged so that no person unless authorised can obtain access thereto otherwise than by the proper entrance,
( b ) arranged so that a person cannot interfere with the apparatus or conductors therein from outside the sub-station, and
( c ) provided with efficient means of ventilation and kept dry.
(2) Every sub-station shall be under the control of an authorised person, and none but an authorised person or a person acting under his immediate supervision shall enter any part thereof in which there may be danger.
(3) Flammable building material shall not be used for the construction of any room or compartment below ground containing electrical apparatus nor in proximity to any such apparatus therein, unless the apparatus is so constructed as to obviate the risk of fire, so far as is reasonably practicable.
(4) Flammable material shall not be stored in a room or compartment mentioned in paragraph (3) of this regulation.
num: 17
paragraphs: Every electrical joint and connection shall be of proper construction as regards conductance, insulation, mechanical strength and protection.
num: 18
paragraphs: Cable couplers for circuits operating at a voltage exceeding 250 volts shall be—
( a ) of a type suitable for the cable on which they are to be installed,
( b ) of such design and proportion as is suitable having regard to the most onerous conditions under which they will operate,
( c ) provided with covers or hoods and suitable seals which will cover and protect the exposed ends when the couplers are disconnected,
( d ) provided with cable glands and joint sealing rings to prevent the ingress of moisture, and
( e ) interlocked, either mechanically or electrically, so that they cannot be inserted or withdrawn under load.
num: 19
paragraphs: (1) Where it is necessary to prevent danger, adequate precautions shall be taken in relation to electrical apparatus either by earthing or by other suitable means to prevent any metal other than a conductor from becoming electrically charged.
(2) Every earthing conductor required to be installed by virtue of paragraph (1) of this regulation shall have a cross-sectional area of not less than 14 square millimetres (0·022 square inches); provided that this paragraph shall not apply in relation to an earthing conductor which is—
( a ) the metallic covering of a cable, or
( b ) a part of an overhead line, or
( c ) in the case of a multi-core cable, whether a flexible cable or not, one of the conductors in that cable.
(3) No automatic circuit opening device shall be placed in any earthing conductor provided pursuant to this regulation.
(4) Earthing conductors and their connections shall be efficiently protected against corrosion.
(5) Earth electrodes shall be efficiently constructed, installed and maintained.
num: 20
paragraphs: (1) In every two-wire system at the surface of a mine which is used wholly or mainly for the purposes of traction and in which the running rails form part of the circuit, the pole to which such rails are connected shall be connected to earth in such manner as will ensure immediate electrical discharge without danger.
(2) In every two-wire circuit in which the supply of electricity is derived from the secondary winding of a single phase transformer, being a circuit used solely for indicating instruments or other accessories of switchgear including any fixed lights associated therewith, one pole shall be connected at one place, and one place only, to earth.
(3) In every circuit in which alternating current at a voltage exceeding 25 volts is used the neutral point shall be connected at one place, and one place only, to earth; provided that in the case of a three phased three-wire circuit in which the supply of electricity is derived from the secondary winding of a three phase transformer, being a circuit used solely for indicating instruments or other accessories of switchgear including any fixed lights associated therewith, one pole of the circuit instead of the neutral point may be so connected to earth.
(4) Any system or circuit, other than those mentioned in the preceding paragraphs of this regulation, which is connected to earth shall be so connected at one place and one place only.
(5) No automatic circuit opening device shall be placed in any connection to earth mentioned in the foregoing paragraphs of this regulation.
num: 21
paragraphs: Where two or more earth plates are used pursuant to Regulation 19 or 20 of these Regulations and the electrical resistance between them or any two of them exceeds two ohms, they shall be connected by a conductor having a cross-sectional area of not less than 14 square millimetres (0·022 square inches); provided that if any such earth plate used pursuant to the said Regulation 19 is inaccessible, the provisions of this Regulation shall not apply in relation to that earth plate but the resistance between any other earth plates so used and the general mass of earth shall not exceed two ohms.
num: 22
paragraphs: (1) ( a ) All conductors, unless they are placed and safeguarded so as to prevent danger, shall be covered with insulating material; provided that this paragraph shall not apply to circuits in which the voltage does not exceed 25 volts.
(2) Insulating material used for insulating a conductor shall be—
( a ) of mechanical strength sufficient for its purpose, and
( b ) so far as practicable, of such character or so protected as fully to maintain its insulating properties under working conditions including conditions as to temperature and moisture.
(3) Every conductor forming part of an electrical system, except the outer conductor of a concentric cable, shall be kept efficiently insulated from earth; provided that—
( a ) in the case of a system with polyphase supply, the neutral point or starpoint thereof may be connected at one place, and one place only, to earth at the surface of the mine, and
( b ) in the case of a system with single-phase or direct current supply, the mid-voltage point may be connected at one place, and one place only, to earth at the surface of the mine.
(4) An efficient means shall be provided in relation to every electrical system whereby an indication is given of any defect in the insulation thereof.
(5) The insulation resistance of a circuit, other than the insulation resistance of any conductor which is an earthing conductor, shall be maintained so that in normal working the leakage current does not exceed one ten thousandth part of the maximum current for which that circuit is designed; provided that this paragraph shall apply neither to overhead lines on the surface nor to telephone or signalling apparatus.
num: 23
paragraphs: (1) Subject to paragraphs (3) and (4) of this regulation every cable, other than a flexible cable used to supply portable or transportable apparatus, containing a conductor and which is required by these Regulations to be covered with insulating material, shall be protected throughout its length by a suitable metallic covering and all the conductors forming a particular section of the same system shall be contained in a single such covering.
(2) A metallic covering mentioned in paragraph (1) of this regulation shall have a conductance throughout not less than half that of the conductor having the greatest current-carrying capacity enclosed thereby; provided that in the case of a cable of which the metallic covering is wire and which is covered with a lead sheath, the conductance of that sheath may be taken into account for the purposes of this paragraph if plumbed joints are used where the cable is jointed or terminated.
(3) Where it is necessary to move an electric motor from time to time to adjust the tension of a driving belt, rope or chain, such length of cable as is requisite may be protected by flexible metallic tubing instead of a metallic covering, but a separate earthing conductor having a cross-sectional area of not less than 14 square millimetres (0·022 square inches) shall be provided therewith.
(4) Nothing in this regulation shall apply to a cable in any circuit in which the voltage does not exceed 250 volts D.C. or 125 volts A.C.
num: 24
paragraphs: (1) Wherever any cable (including a flexible cable) protected by a metallic covering is connected to other electrical apparatus, the metallic covering shall be securely attached to the apparatus.
(2) Any material insulating a conductor in a cable shall be efficiently sealed at any point at which the conductor is connected to other electrical apparatus if its insulating property at that point might be diminished by moisture.
num: 25
paragraphs: (1) Subject to paragraph (5) of this regulation, single-core flexible cable shall not be used for supplying portable or transportable apparatus at a mine; provided that where the conductance required for the live conductor is such as to render the use of a two-core or multi-core cable impracticable there may be used single-core cables of such construction and bonded and earthed in such manner as may be approved by the Minister or an inspector.
(2) Every flexible cable used for supplying portable or transportable apparatus at a mine shall comprise an earthing conductor having throughout a cross-sectional area and conductance neither of which is less than that of the largest current carrying conductor in the cable.
(3) Every flexible cable so used in a circuit in which the voltage exceeds 250 D.C. or 125 A.C. shall be protected throughout by—
( a ) a metallic covering containing all conductors forming a particular section of the circuit and having a conductance not less than half that of the conductor enclosed thereby having the greatest-current carrying capacity, other than the earthing conductor, or, where that is impracticable, having a conductance not less than that of a copper conductor with a cross-sectional area of 14 square millimetres (0·022 square inches), or
( b ) a screen of wires containing as many of the conductors forming a particular section of the circuit as the particular circumstances permit and having a conductance not less than that of a copper conductor with a cross-sectional area of 14 square millimetres (0·022 square inches), or,
( c ) more than one screen of wires which together enclose and contain as many of the conductors, other than the earthing conductor, as form a particular section of the circuit each being of such construction and having such conductance as may be approved by the Minister,
provided that where the voltage in a circuit exceeds 650 volts the protection shall be by metallic covering described in subparagraph ( a ) of this paragraph.
(4) In addition to the requirement of Regulation 24 (1) of these Regulations but subject to paragraph (5) of this regulation, wherever any flexible cable is connected to other electrical apparatus it shall be attached so as to hold the cable securely and, where necessary having regard to its position, to exclude water, and any screen of wires protecting the cable shall be securely attached to the other apparatus.
(5) Nothing in this regulation shall apply to telephone or signalling apparatus.
num: 26
paragraphs: (1) Subject to Regulation 9 (2) of these Regulations, a portable apparatus operating at a voltage exceeding 125 volts A.C. or 250 volts D.C. shall not be used unless—
(a) in the case of electrical apparatus comprising one or more motors—the motor or one of the motors, as may be appropriate, is rated at more than two horse power, or
(b) in the case of other electrical apparatus—the rated input exceeds two kilovolt amperes.
(2) Every hand-held portable apparatus shall be provided with a switching-off device which shall form part of the apparatus.
num: 27
paragraphs: (1) A portable hand lamp shall not be supplied with electricity at a voltage exceeding 25 volts A.C. or 50 volts D.C.
(2) Every portable hand lamp shall be provided with a properly insulated holder and a substantial guard enclosing the bulb of the lamp.
num: 28
paragraphs: Adequate precautions shall be taken to prevent any telephone wire or signalling conductor wire coming into contact with any cable or other electrical apparatus.
num: 29
paragraphs: (1) This regulation applies to a mine or part of a mine in which the use of lamps or lights, other than permitted lights, is unlawful.
(2) No electrical apparatus, other than apparatus of a type approved by the Minister for the purposes of this regulation, shall be connected into any circuit used for signalling (whether by telephone or otherwise) wholly or partly in a mine or part of a mine, as the case may be, to which this regulation applies; provided that this paragraph shall not apply to apparatus used solely to regulate the movements of cages or carriages in a shaft or unwalkable outlet.
(3) Notwithstanding paragraph (1) of this regulation, telephones which are not of a type approved by the Minister for the purposes of this regulation may be connected into a part of a circuit used for signalling which is on the surface of a mine or is in a part of a mine to which this regulation applies by means of a coupling unit of a type approved by the Minister for the purpose.
(4) No source of current shall be used for operating electrical apparatus in any circuit used for signalling wholly or partly in a mine or part of a mine, as the case may be, to which this regulation applies except as follows:
(a) for direct current signalling, either a battery of three pint porous-pot LeclanchÃ© cells connected in simple series or a source of current approved by the Minister for the purpose,
(b) for alternating current signalling, a transformer of a type approved by the Minister for the purpose, and
(c) for a magneto-call telephone of a type approved by the Minister, a generator of a type specified in that approval.
(5) A part of a circuit used for signalling shall neither be connected to earth nor to more than one source of current; provided that the same line wires may be used for the calling and speaking circuits of telephones.
(6) Any magneto-call telephones connected into any circuit used for signalling shall be connected in parallel, and if such telephones of different types are so connected, each instrument shall include a condenser of a type approved by the Minister for the purpose and connected in shunt with the call bell.
(7) Notwithstanding paragraph (4) of this regulation, direct current bells or relays used in connection with any circuit used for signalling shall, when connected in parallel, be supplied from two identical sources of current connected in opposition.
(8) The voltage in any circuit used for signalling (otherwise than by telephone) below ground in a mine shall not exceed 25 volts A.C. or 50 volts D.C
num: 30
paragraphs: Contact makers used in telephone or signalling apparatus shall be constructed so as to prevent the accidental closing of a circuit.
num: 31
paragraphs: Every person doing work which may result in damage to any electrical apparatus at a mine, being damage which might cause that apparatus to become a source of danger to persons employed at the mine, shall take such steps as may be appropriate to protect the apparatus from such damage.
num: 32
paragraphs: (1) Where any electric welding apparatus is used at a mine the following provisions shall apply, namely—
(a) electricity shall not be taken from the load side except by means of single conductor flexible cables each containing a copper conductor of a cross-sectional area of not less than 14 square millimetres (0·022 square inches) or such other conductor as may be approved by the Minister for the purposes of this subparagraph,
(b) the return current conductor, the article being welded and any associated metal work shall be connected to earth in such a manner as will prevent danger, and
(c) there shall be fitted in position an effective guard to prevent the person using the apparatus from accidentally touching the live parts of the electrode or the electrode holder with the fingers of the hand holding the electrode holder.
(2) Each person using electrical welding apparatus at a mine shall ensure that it is not left in a position so that a person could accidentally come into contact with an electrode or electrode holder whilst live.
num: 33
paragraphs: (1) In any part of the mine below ground in which flammable gas although not normally present is likely to occur in a quantity sufficient to indicate danger, no electrical apparatus shall be used if there is in the normal working thereof a risk of incendive sparking therefrom.
(2) In any such part of a mine all rubbing contacts in any motor shall be arranged or enclosed so as to prevent incendive sparking.
num: 34
paragraphs: (1) A person shall not commence work upon any conductor in a circuit in which the voltage is such that that conductor might be a source of danger to him until that conductor has been made dead and any necessary steps have been taken, whether by earthing or otherwise, to ensure that it will remain dead until the work is finished.
(2) Where it is necessary adequately to prevent danger, there shall be provided and kept permanently in position suitable insulating stands or screens and such stands or screens shall be maintained in sound condition.
(3) Where it is necessary adequately to prevent danger, there shall be provided and used portable insulating stands, screens, boots, gloves, or other suitable means and such stands, screens, boots, gloves or other such means shall be periodically examined by a person authorised by the manager in that behalf.
(4) Adequate working space and means of access, free from danger, shall be provided in relation to all electrical apparatus which has to be worked or attended to by any person.
num: 35
paragraphs: (1) The manager shall make and ensure the effective carrying out of arrangements for the testing by a competent person appointed by him of all parts of every circuit at a mine—
(a) upon the completion of every new installation and every major alteration to an existing installation as regards each of the following, namely,
(i) verification of polarity,
(ii) the conductance of the earth conductor and earth plate or earth rods,
(iii) the effectiveness of the earth loop impedance,
(iv) the effectiveness of every earth-leakage circuit breaker, and
(v) the insulation resistance of every circuit,
and,
(b) at intervals not exceeding six months or such longer interval as an inspector may, by notice served on the manager, permit, as regards the matters mentioned in clauses (i), (iv) and (v) and together with those mentioned either in clause (ii) or in clause (iii) of subparagraph (a) of this paragraph.