1、BRITISH STANDARD BS 6907-3: 1988 Electrical installations for open-cast mines and quarries Part 3: Recommendations for equipment and ancillaries UDC 622.3:622.271.3:622.812.2:621.31.005:.022.7:614.8BS6907-3:1988 This British Standard, having been prepared under the directionof the Mining and Quarryi
2、ng Requisites StandardsCommittee, was published under the authority ofthe Board of BSI and comes intoeffect on 30 September 1988 BSI 07-1999 The following BSI references relate to the work on this standard: Committee reference MQE/23 Draft for comment 86/75882 DC ISBN 0 580 16370 9 Committees respon
3、sible for this British Standard The preparation of this British Standard was entrusted by the Mining and Quarrying Requisites Standards Committee (MQE/-) to Technical Committee MQE/23, upon which the following bodies were represented: Associated Offices Technical Committee British Coal China Clay As
4、sociation Electric Cable Makers Confederation Electrical Contractors Association Engineering Equipment and Materials Users Association Federation of Civil Engineering Contractors Federation of Manufacturers of Construction Equipment and Cranes Health and Safety Executive Independent Engineering Insu
5、rers Committee Institution of Mining and Metallurgy Amendments issued since publication Amd. No. Date of issue CommentsBS6907-3:1988 BSI 07-1999 i Contents Page Committees responsible Inside front cover Foreword ii 1 Scope 1 2 General 1 3 Rotating machines 1 4 Transformers 2 5 Static converters 2 6
6、Switching devices 2 7 Cable selection and application 2 8 Cable connectors 4 9 Cable drums 4 10 Control circuits and control devices 5 11 Safety circuits and safety devices 6 12 Fire detection and protection systems 6 Appendix A Typical analysis sheet for fire protection systems 9 Publications refer
7、red to Inside back coverBS6907-3:1988 ii BSI 07-1999 Foreword This Part of BS6907 has been prepared under the direction of the Mining and Quarrying Requisites Standards Committee. BS6907 is based on the International Electrotechnical Commissions publication IEC621 “Electrical installations for outdo
8、or sites under heavy conditions (including open-cast mines and quarries)” and, like that publication, is published in Parts as follows. Part 1: Glossary; Part 2: General recommendations for protection against direct contact and electric shock; Part 3: Recommendations for equipment and ancillaries; P
9、art 4: Recommendations for winning, stacking and processing machinery, pumps and low signal level and communications systems; Part 5: Recommendations for operation. BS6907 sets out the guiding principles for the installation and operation of electrical equipment so as to ensure safety of persons, li
10、vestock, property and proper functioning of the plant. It applies to the installation and operation of electrical apparatus and systems associated with outdoor sites under heavy conditions, including open-cast mines, quarries, stockpiles, etc. It applies particularly to electrical apparatus and syst
11、ems used for the following: a) winning, stacking and primary processing machinery; b) secondary processing machinery; c) conveyor systems; d) pumping and water supply systems; e) movable railway systems; f) control, signal, supervisory and communication systems. BS6907 does not cover temporary and p
12、rovisional places of work in the open, such as building sites and earth-moving sites, unless the equipment used is similar to that used in surface mining applications. It takes account of British practice, electrical regulations and law and thereby differs in several respects from the IEC publicatio
13、n. Both cover a subject not previously the subject of an international standard or a British Standard. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standa
14、rd does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages1 to 10, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporat
15、ed. This will be indicated in the amendment table on theinside front cover.BS6907-3:1988 BSI 07-1999 1 1 Scope This Part of BS6907 gives recommendations for good practice for the safe and efficient installation and use of electrical equipment and ancillaries. For winning, stacking and processing mac
16、hinery, pumps and low signal level and communications systems, exemptions from these recommendations and supplementary recommendations are given in BS6907-4, which should, therefore, be read in conjunction with this Part. NOTE 1A glossary of terms used in this standard is given in BS6907-1. NOTE 2Th
17、e titles of the publications referred to in this standard are listed on the inside back cover. 2 General 2.1 Design and selection Design and selection of apparatus or equipment should be on the basis of expected loading, operating characteristics and cyclic duty taking into consideration the protect
18、ion required in special and arduous environmental, operational, transportation and storage conditions including: high altitude; low and/or high ambient temperature; supply voltage variations; supply frequency variations; insecure power supply and transients; high or low humidity; environment (dust,
19、wind pressure, marine atmosphere, etc.); flammable and/or explosive materials and/or atmosphere; vermin, including rodents or other small animals; localities prone to natural catastrophes; ecological impact. In order to ensure that correct design parameters are selected, mutual agreement should be r
20、eached between the user and the supplier as to the quantitative and/or qualitative conditions. 2.2 Relevant standards All electrical apparatus or equipment should be in accordance with the relevant British Standards. 2.3 Materials Materials used in the construction of apparatus or equipment should b
21、e appropriate for the operational conditions, including temperature, altitude, moisture, etc. 2.4 Protection Protection should be provided against damage, explosion, and/or over-heating during normal operation and expected fault conditions. 2.5 Operating conditions Apparatus or equipment should be d
22、esigned to meet such conditions as vibration, acceleration, deceleration, slewing and angles of inclination (tilting and mounting) which may occur under expected operational conditions. 2.6 Site conditions Apparatus or equipment should be installed so that design features such as cooling systems are
23、 not impaired by external factors such as position, blocking of ventilation ducts, hostile environment, etc. 2.7 Earth terminal An earth terminal should be provided on all enclosures of apparatus and equipment operating at a voltage in excess of extra low voltage. NOTESee the IEE Regulations for the
24、 definition of extra low voltage. 2.8 Noise limitations Consideration should be given in the design to limit the emission of noise. 2.9 Pollution by cooling medium (coolant) Adequate precautions should be provided to prevent spillage of the cooling medium causing pollution of the environment, for ex
25、ample, groundwater storages, harbours, waterways, soil, etc. Where equipment with a flame-retardant cooling medium is used, the installation should be so arranged as to inhibit the possible atmospheric contamination and noxious effects of the cooling medium. 3 Rotating machines 3.1 Mechanical constr
26、uction Rotating machines used in applications where high acceleration, overspeed, reversing or braking may be employed should be designed and constructed so as to withstand expected stresses that may occur to parts such as rotor windings or cages, stators, stator end windings, shafts and couplings.
27、3.2 Mechanical protection Rotating machines should be so constructed and guarded as to prevent contact with moving parts.BS6907-3:1988 2 BSI 07-1999 4 Transformers 4.1 Transformers subject to movement or vibration The core, coils, internal leads and enclosure should be adequately braced for arduous
28、operating conditions (see2.1). 4.2 Enclosures Transformers should preferably be totally enclosed. All liquid-filled transformers should have a pressure relief valve. Any breather or pressure relief device should be fitted in such a way as to minimize degradation of the cooling medium (coolant) throu
29、gh condensation, or ingress of moisture. 4.3 Dust exclusion Transformers of the dry type, including their cooling system, should be protected against the harmful ingress of dust. 4.4 Protection from fire Where fire hazards to personnel or plant structure exist, the use of dry type transformers or th
30、ose employing a non-toxic flame retardant cooling medium are recommended. Where a flammable cooling medium is used, adequate catchment facilities and safe means of egress should be provided. 5 Static converters 5.1 Over-voltage limitation Where static converters are used, precautions should be taken
31、 to protect against harmful effects of over-voltage and transient over-voltage conditions. 5.2 Interference with communication and control systems Protective or control measures should be taken to restrict the effect of electrical energy that may cause interference to communication and/or electrical
32、 control equipment. Cognizance should be taken of standards for radio-frequency suppression and permissible harmonic currents. 5.3 Electrical coupling The converter installation should include, where necessary, appropriate means to prevent spurious operation due to electrical coupling (e.g. resistiv
33、e, inductive or capacitive) with other apparatus. 5.4 Protection against interaction between earthing systems The converter installation should include, where necessary, appropriate means to prevent interaction between the earthing systems of the input, output and control circuits. 5.5 Limitation of
34、 harmonics The acceptable level of harmonic generation should be arrived at in consultation with the equipment manufacturer and the supply authority. 6 Switching devices 6.1 Prevention of unintentional operation Switching devices should be designed, constructed and installed in such a way that no un
35、intentional switching may be caused under expected operational and risk conditions. 6.2 Isolators Isolators should be provided with suitable means to enable them to be locked in the isolated or earthed position. 6.3 Interrupting capability Switching devices which are not suitable for interrupting lo
36、ad or fault currents should be interlocked with a suitable interrupting device for that circuit and be fitted with a warning label. 6.4 Personnel protection Switching devices should be designed, constructed and installed so as to prevent electrical and mechanical hazards to personnel. 7 Cable select
37、ion and application 7.1 Phase conductors Selection of phase conductor size should take into consideration the expected load current, short-circuit current and duration of fault, voltage drop and the mechanical strength required for the expected method of handling. The voltage drop should be calculat
38、ed for both starting and maximum load conditions. Where supplying a cyclic load, the current-carrying capacity of the phase conductors may be based on the equivalent r.m.s. value of the cyclic load, other conditions permitting. 7.2 Protective conductor All multicore cables of the movable distributio
39、n, drum and trailing types should contain a protective conductor. In high-voltage systems, it is essential that special measures be taken to guard against deterioration of the earthing circuit. This may be achieved by either: a) monitoring the protective conductor against increase in resistance by t
40、he use of pilot cores, high-frequency monitoring or other means; or b) using specially designed cables in accordance with 9.3, whether or not they are used on a drum. The protective conductor may be in the form of core(s) and/or screen(s).BS6907-3:1988 BSI 07-1999 3 For certain classes of movable di
41、stribution cables, the armouring may, subject to 7.3, form the protective conductor. 7.3 Armouring as protective conductor Where the cross-sectional area of a single composite strand of the armouring is greater than 6mm 2 , the metallic armouring of a movable distribution cable may be used as a prot
42、ective conductor provided that the security against breakage of the armouring (taking into account strength, elongation, lay, etc.) is at least equal to that of all the conductors; and provided that the armour conductivity is at least equal to that of a protective conductor of the required nominal c
43、ross-sectional area which would otherwise be required. 7.4 Limiting temperatures under short-circuit Cables should be selected so as to ensure that the maximum allowable conductor temperature, considering the type of insulation, is not exceeded under expected short-circuit fault conditions (see15.3.
44、2 of BS6907-2:1988). 7.5 Semiconducting layers Where cables are fitted with substantial longitudinal semiconducting layers for the purpose of providing a current path to the protective conductor in the event of a fault, the resistance between the semiconducting element and the protective conductor s
45、hould be tested to ensure that it is suitable to carry the prospective fault current. 7.6 Provision of screens and/or armouring for cables above 1 000 V Where flexible cables are handled manually while energized, they should have metallic screens and/or armouring or should be provided with conductin
46、g elastomeric screens of substantial cross-sectional area and so placed as to limit the touch and step voltages, that may arise in the event of a cable fault. In cases where cables are handled only by means of special insulated tools, these recommendations will apply only for voltages above 4 000V.
47、7.7 Identification of protective conductor 7.7.1 For cables rated up to and including 1 000V, in which the protective conductor is insulated, such insulation, or outer taping, should be distinctly and indelibly coloured green and yellow over its whole length so that in any 15mm length one of these c
48、olours should cover at least 30% and not more than70% of the surface, the other colour covering the remainder of the surface. 7.7.2 For cables rated at above 1 000V, in which the protective conductor is insulated, such insulation or outer taping should at least be identified at each end by the green
49、/yellow colour combination applied in accordance with 7.7.1. NOTESuitable supplementary identification may also be used. 7.8 Terminations of flexible cables Flexible cables should be installed in such a manner that all forms of mechanical stress are avoided at the conductor termination and gland arrangements. 7.9 Power cable twist limitation 7.9.1 Flexible cables are generally not designed to be twisted about their longitudinal axes, therefore, in installations where it is not possible to avoid such twisting, the design of the flexible cable and its installation
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