1、BRITISH STANDARD BS787-2:1968 Incorporating Amendment No.1 Specification for Mining type flameproof gate-end boxes Part 2: Gate-end boxes with air-break circuit-breakers (for use on 3-phase a.c. circuits up to650volts)BS787-2:1968 This BritishStandard, having been approved by the CollieryRequisites
2、Industry Standards Committee and endorsed by the Chairman oftheEngineering Divisional Council, was published undertheauthority of the GeneralCouncil on 30August1968 BSI01-2000 The following BSI references relate to the work on this standard: Committee reference CRE/16 Draft for comment66/9630 ISBN 0
3、 580 00277 2 Co-operating organizations The Colliery Requisites Industry Standards Committee, under whose supervision this BritishStandard was prepared, consists of representatives from the following Government and scientific and industrial organizations: Association of Mining Electrical and Mechani
4、cal Engineers* British Electrical and Allied Manufacturers Association* British Steel Industry Federation of Associations of Mining Equipment Manufacturers Institution of Electrical Engineers Institution of Mechanical Engineers Institution of Mining Engineers Mechanical Handling Engineers Associatio
5、n Ministry of Power* National Association of Colliery Managers National Coal Board* The Government department and industrial organizations marked with an asterisk in the above list were directly represented on the committee entrusted with the preparation of this BritishStandard. Amendments issued si
6、nce publication Amd. No. Date of issue Comments 422 February 1970 Indicated by a sideline in the marginBS787-2:1968 BSI 01-2000 i Contents Page Co-operating organizations Inside front cover Foreword ii 1 Scope 1 2 Definitions 1 3 Service conditions 3 4 Ratings 3 5 Marking 3 6 Design and construction
7、 4 7 Tests 8 8 Information to be supplied to the manufacturer with the enquiry 10 Appendix A Metric values 12 Figure 1 Arrangement of busbar chamber end flange, terminals andinterconnections 13 Figure 2 Busbar interconnecting trunk 14 Figure 3 Skid coupling arrangement 15 Figure 4 Busbar end cover 1
8、6BS787-2:1968 ii BSI 01-2000 Foreword This standard makes reference to the following BritishStandards: BS88, Cartridge fuses of voltage ratings up to660volts. BS159, Busbars and busbar connections. BS229, Flameproof enclosure of electrical apparatus. BS279, 100-ampere flameproof plugs and sockets (r
9、estrained type). BS542, Cable glands and sealing boxes for association with apparatus for use at mines. BS862, Air-break circuit-breakers (including totally-enclosed and flameproof types) for voltages not exceeding660volts. BS936, Oil circuit-breakers for medium-voltage alternating-current systems.
10、BS1259, Intrinsically safe electrical apparatus and circuits for use in explosive atmospheres. BS3101, Intrinsically safe remote-control circuits associated with restrained plugs and sockets for use in coal mines. BS3454, 3.3kV300A interchangeable bolted flameproof cable couplers and adaptors (inclu
11、ding660V300A adaptors) primarily for use in mines. This BritishStandard has been prepared, under the authority of the Colliery Requisites Industry Standards Committee, to standardize the main features of gate-end boxes used primarily in coal mining in the United Kingdom. It is recognized that the te
12、rm “gate-end box” is quite general and may be applied to boxes containing different essential components, such as contactors, circuit-breakers, lighting transformers etc., depending upon the purpose for which they are to be used. BS787 was first issued in1938, and has been revised and re-issued as B
13、S787-1:1965 to cover gate-end boxes in which the essential apparatus is an air-break electrically operated contactor. This additional specification, designated as BS787-2, extends the scope of the original BS787 by covering gate-end boxes in which the essential apparatus is an air-break circuit-brea
14、ker. It is envisaged that additional parts of this BritishStandard will be issued to cover other forms of gate-end boxes, such as lighting units and drill units. NOTEWhere metric equivalents have been given (seeAppendix A), the figures in imperial units are to be regarded as the standard. The metric
15、 conversions are approximate. More accurate conversions should be based on the tables in BS350-1, “Conversion factors and tables”. 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. Comp
16、liance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pagesi andii, pages1 to16 and a back cover. This standard has been updated (see copyright date) and may have had amendments incorpo
17、rated. This will be indicated in the amendment table on the inside front cover.BS787-2:1968 BSI 01-2000 1 1 Scope This BritishStandard specifies requirements for mining type flameproof gate-end boxes with air-break circuit-breakers for use on3-phase a.c. circuits up to650volts. 2 Definitions For the
18、 purposes of this BritishStandard the following definitions apply: 2.1 gate-end box a flameproof enclosure containing electrical apparatus such as control gear, switchgear and/or protective gear, designed primarily for use underground NOTEIn this particular instance the apparatus is essentially an a
19、ir-break circuit-breaker with associated equipment to provide control and protection of other electrical apparatus. 2.2 isolator a mechanical device capable of opening or closing a circuit, under conditions of no load or negligible current 2.3 air-break circuit-breaker a device, hand or power operat
20、ed, capable of making, carrying and breaking currents in air, at substantially atmospheric pressure, under normal circuit conditions and also making, carrying for a specified time, and breaking currents under specified abnormal conditions such as those of short-circuit 2.4 cable sealing and dividing
21、 box a box designed to receive and protect the end of the cable, with provision for sealing the conductors and the insulating material of the cable with a suitable compound, and having a cable gland for attaching the cable to the box, together with any terminals provided for connection to the conduc
22、tors of the cable within the box. The box may form part of, or be detachable from, the apparatus with which it is associated 2.5 detachable cable sealing box a cable sealing box so designed that it can be detached from associated apparatus without cutting the cable and without disturbing the sealing
23、 2.6 cable coupling unit (flit plug) a unit consisting of a cable sealing box and cable gland together with means for connecting the cable conductors to insulated contact tubes within the sealing box, which is designed to receive the cable; toprovide room to spread and connect the cores; to protect
24、the cores; to allow for the attachment of the cablegland; to provide for sealing the insulating materials of the cable, and to facilitate ready connection to or disconnection from a similar unit or other apparatus 2.7 cable coupler adaptor a device used to connect a cable coupling unit to apparatus.
25、 It may either be separate from or integral with the flameproof enclosure of the apparatus to which the cable coupling unit is to be connected for the purposes of this standard, the term “adaptor” also includes the unit to connect other types of cable terminations to apparatus 2.8 restrained plug an
26、d socket a plug and socket, the two portions of which, when engaged, are designed to be held together by an operating bolt, or a screwed union ring, or some other equivalent device. Such a device enables the plug to be readily inserted or withdrawnBS787-2:1968 2 BSI 01-2000 2.9 bolted plug and socke
27、t a plug and socket, the two portions of which, when fully engaged, are designed to be held together by one or more bolts or screws, or studs and nuts, in such a way that they cannot be disengaged without the use of tools 2.10 flameproof enclosure an enclosure for electrical apparatus that will with
28、stand, without injury, any explosion of the prescribed flammable gas that may occur within it, under practical conditions of operation within the rating of the apparatus (and recognized overloads, if any, associated therewith) and will prevent the transmission of flame such as will ignite the prescr
29、ibed flammable gas which may be present in the surrounding atmosphere (see7.2.4) 2.11 intrinsically safe circuit a circuit in which any electrical sparking that may occur in normal working under the conditions specified by the certifying authority, and with the prescribed components, is incapable of
30、 causing an ignition of the prescribed flammable gas or vapour (see7.2.4) 2.12 rating the value assigned by the maker to some limits of performance under certain specified conditions known as the “rated conditions” 2.13 local control external control by means of an external handle for a hand operate
31、d circuit-breaker, or by push button for an electrically operated circuit-breaker 2.14 remote control control by means of a manually operated switch or push button located at a point separate from the gate-end box 2.15 automatic control control by means of any device other than a manually operated s
32、witch or push button 2.16 sequence interlocking means by which operation is made dependent on the fulfilment of other prescribed conditions 2.17 overcurrent release a device that causes the circuit-breaker to open the circuit automatically when the current exceeds the predetermined value at which th
33、e release has been adjusted to operate 2.18 inverse time lag overcurrent release a device that retards the tripping of the circuit-breaker by a time inversely dependent upon the magnitude of the overcurrent 2.19 undervoltage release a device which causes the circuit-breaker to open the circuit if th
34、e voltage falls below a predetermined value 2.20 shunt release a device which causes the circuit-breaker to open when energized from a source of voltage that may be independent of the circuit in which the circuit-breaker is connectedBS787-2:1968 BSI 01-2000 3 3 Service conditions Gate-end boxes in a
35、ccordance with this specification are suitable, within the limits of their ratings, for installations where the service conditions are not more severe than the following: 1) Ambient temperature. A peak value not exceeding40 C with an average value not exceeding35 C over24-hour periods. 2) Altitude.
36、An altitude not exceeding3300feet(1000m) above sea level. NOTEWhen a gate-end box intended for service at high altitudes is tested near sea level, the limits of temperature rise, as indicated in 6.16, should be reduced by1% for each1000feet(300m) above sea level at which the circuit-breaker is inten
37、ded to work in service. The correction does not apply for altitudes below3300feet (1000m). 4 Ratings 4.1 Voltages. The maximum voltage shall be650volts. The following supply voltages shall be regarded as standard: 400,440,500,550,600 and650volts. Boxes designed for other than the standard voltages u
38、p to650volts, provided they satisfy all other requirements specified herein, shall be deemed to comply with this standard. Standard boxes shall be suitable for a voltage variation at least10% below and at least6% above the declared voltages of the supply for which they are designed, subject again to
39、 the maximum of650volts. 4.2 Supply frequencies. The standard frequency shall be50Hz(c/s). Gate-end boxes designed for other frequencies within the range of2560Hz(c/s), provided they satisfy all other requirements specified herein, shall be deemed to comply with this standard. 4.3 Currents 4.3.1 Cur
40、rent rating of boxes. The preferred continuous current ratings of boxes shall be: 200,300,400amperes Boxes designed for other ratings, provided they satisfy all other requirements specified herein, shall be deemed to comply with this standard. 4.3.2 Current rating of busbars. The current rating of b
41、usbars, where fitted, shall be at least equal to the circuit-breaker rating, with a minimum rating of300amperes. 5 Marking 5.1 Nameplates. All gate-end boxes shall be permanently marked with the following particulars: 1) The name of the manufacturer or his agent. 2) Manufacturers type or reference.
42、3) Manufacturers serial number. 4) Maximum rated current in amperes. 5) Making capacity peak (kA). 6) Breaking capacity (kA). 7) Voltage or voltage range. 8) Frequency. 9) The number of the flameproof certificate and the number or numbers indicating the group of gases and vapours covered by the cert
43、ificate. 10) A reproduction of the registered flameproof mark (if the manufacturer holds a licence to apply this mark), or any other mark required by the Ministry of Power. 11) Where applicable the intrinsic safety certificate details as required by the Ministry of Power. 12) Additional marking as m
44、ay be required by any other certifying authority. 5.2 Terminals. Terminal markings, if required, for incoming and outgoing connections shall be agreed between the manufacturer and the purchaser. 5.3 Busbar interconnecting trunks. All busbar interconnecting trunks (see6.3) shall be permanently marked
45、 with the following particulars:BS787-2:1968 4 BSI 01-2000 1) Manufacturers name or trade mark. 2) Manufacturers type or reference. 5.4 Busbar end covers. All busbar end covers (see6.4) shall be marked with the following particulars: 1) Manufacturers name or trade mark. 2) Manufacturers type or refe
46、rence. 5.5 Diagrams. Diagrams of connections, which shall be durable and legible, shall be securely attached in an accessible position within the main chamber. 6 Design and construction A gate-end box in accordance with this specification shall comply with the requirements of BS229 1)(Note) and shal
47、l have been certified, by the Ministry of Power, as flameproof for Group1 gases (methane/firedamp). The gate-end box may also be certified for any group of gas by any appropriate certifying authority, as may be required. Unless otherwise agreed between manufacturer and purchaser, no external compone
48、nt shall be made of aluminium, magnesium or titanium, neither shall any alloy containing aluminium and/or magnesium and/or titanium be used unless the total content of these three constituents does not exceed15% by weight, and in which the content of magnesium and titanium together does not exceed10
49、% by weight. No external part shall be painted or coated with preparations containing, in metallic form, aluminium, magnesium or titanium. NOTEThese limitations have been imposed to avoid the hazards of incendive sparking due to friction between rusty steel and the metals described. NOTEWhen applying for flameproof certification, it will be necessary, for compliance with BS229 1) , for the manufacturer to specify the types of fittings for which he has made provision in accordance with6.2 to6.6 inclusive. The following subclauses relate to the basic unit: The
