1、| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | BRITISH STANDARD BS 7884 : 1997 ICS 29.060
2、.01; 29.240.20 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW Specification for Copper and copper-cadmium stranded conductors for overhead electric traction and power transmission systemsBS 7884 : 1997 This British Standard, having been prepared under the direction of the Eng
3、ineering Sector Board, was published under the authority of the Standards Board and comes into effect on 15 February 1997 BSI 1997 The following BSI references relate to the work on this standard: Committee reference NFE/34 Draft for comment 95/716711 DC ISBN 0 580 26853 5 Amendments issued since pu
4、blication Amd. No. Date Text affected Committees responsible for this British Standard The preparation of this British Standard was entrusted by Technical Committee NFE/34, Copper and copper alloys, upon which the following bodies were represented: British Bathroom Council British Cable Makers Confe
5、deration British Non-Ferrous Metals Federation British Refrigeration Association British Valve and Actuator Manufacturers Association Copper Development Association Inco Europe Limited London Metal Exchange Non-Ferrous Metal Stockists Transmission and Distribution Association (BEAMA Limited) The fol
6、lowing bodies were also represented in the drafting of the standard, through subcommittees and panels: British Railways Board Institution of Incorporated Executive Engineers Society of Motor Manufacturers and TradersBS 7884 : 1997 BSI 1997 i Contents Page Committees responsible Inside front cover Fo
7、reword 1 Specification 1 Scope 1 2 References 1 3 Definitions 1 4 Requirements 1 5 Rounding of results 2 6 Selection of test samples 6 7 Inspection documentation 6 8 Marking, labelling and packaging 6 Annexes A (informative) Information to be supplied by the purchaser 7 B (informative) Notes on the
8、calculation of tables 3 and 4 7 C (normative) Wrapping test 7 D (normative) Electrical resistance test 8 Tables 1 Physical, mechanical and electrical properties of solid, circular, hard drawn copper wire 3 2 Physical, mechanical and electrical properties of solid, circular, hard drawn copper alloy w
9、ire 3 3 Physical, mechanical and electrical properties of hard drawn copper stranded conductors 4 4 Physical, mechanical and electrical properties of hard drawn copper alloy stranded conductors 5 5 Lay ratios of stranded conductors 5 B.1 Increase in length due to stranding 7 B.2 Stranding constants
10、7 D.1 Factors for correcting resistance: hard drawn high conductivity copper of conductivity 97 % IACS 8 D.2 Factors for correcting resistance: hard drawn copper-cadmium 9 List of references Inside back coverii BSI 1997 BS 7884 : 1997 Foreword This British Standard has been prepared by Technical Com
11、mittee NFE/34/2. This revision supersedes BS 125 : 1970 and BS 2755 : 1970, which are withdrawn. Copper and copper alloy conductors for overhead electric traction are also dealt with in BS 23. In this revision due regard has been given to the work of the International Organization for Standardizatio
12、n (ISO) when reviewing the testing requirements, properties and physical dimensions of conductors. Where applicable, if possible, the requirements of this British Standard have been aligned with those of corresponding International Standards. However, it has been necessary to go outside ISO dimensio
13、ns to specify conductors that are suitable for use with fittings currently in use. Compliance 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, pages i and ii, pages 1 to 10, an inside bac
14、k cover and a back cover. BSI 1997 1 BS 7884 : 1997 Specification 1 Scope This British Standard specifies requirements for solid and stranded circular conductors for overhead power transmission systems and overhead electric traction systems. It specifies the requirements for material composition, di
15、mensions, mechanical properties, electrical resistance, stranding, and other characteristics for hard-drawn high conductivity copper and copper alloy conductors. NOTE. Guidance on information that should be supplied by the purchaser is given in annex A. 2 References 2.1 Normative references This sta
16、ndard incorporates, by dated or undated reference, provisions from other publications. These normative references are made at the appropriate places in the text and the cited publications are listed on the inside back cover. For dated references, only the edition cited applies: any subsequent amendm
17、ents to or revisions of the cited publication apply to this British Standard only when incorporated in the reference by amendment or revision. For undated references, the latest edition of the cited publication applies, together with any amendments. 2.2 Informative references This British Standard r
18、efers to other publications that provide information or guidance. Editions of these publications current at the time of issue of this standard are listed on the inside back cover, but reference should be made to the latest editions. 3 Definitions For the purpose of this British Standard the followin
19、g definitions apply. 3.1 solid conductor Conductor consisting of one wire of circular cross-section. 3.2 stranded conductor Conductor consisting of a number of circular wires of the same nominal diameter, having a central core wire surrounded by one or more layers of helically laid wires. When the c
20、onductor consists of more than one layer, alternate layers are stranded in opposite directions. 3.3 wire diameter Mean of two micrometer measurements taken at right angles to each other at any one cross-section of the wire. 3.4 circularity Degree by which the cross-section of a wire conforms to a ci
21、rcle. NOTE. Circularity is ascertained by comparing the maximum and the minimum diameters measured at the same cross-section of the wire. 3.5 direction of lay For stranded conductors, the direction in which the helically laid outer strands are wound round the central core wire. NOTE. Wires conform t
22、o the direction of the central part of the letter Z when the conductor is held vertically and viewed from the side. For left-hand lay, the wires conform to the central part of the letter S when the conductor is held vertically and viewed from the side. 3.6 lay length Axial length of one complete tur
23、n of the helix formed by an individual wire in a stranded conductor. 3.7 lay ratio Ratio of the lay length to the external diameter of the corresponding layer of wires in the stranded conductor. 4 Requirements 4.1 Composition Copper conductors shall be manufactured from high conductivity copper wire
24、s conforming to the composition requirements for BS 6926 : 1988, grade C100, C101 or C102, the choice of grade being at the discretion of the manufacturer. Copper alloy conductors shall be manufactured from wires conforming to the composition requirements for BS 2873 : 1969, alloy C108 or other comp
25、osition requirements agreed between the purchaser and the supplier. 4.2 Dimensions, tolerances and masses 4.2.1 Solid conductors The dimensions and masses of solid conductors shall conform to tables 1 and 2. The conductor shall not depart from circularity (see 3.4) by more than 2 % of the nominal di
26、ameter. 4.2.2 Component wires of stranded conductors The dimensions of component wires for stranded conductors before stranding shall conform to tables 1 and 2, as appropriate. The cross-section of any wire before stranding shall not depart from circularity (see 3.4) by more than 2 % of the nominal
27、wire diameter. The mass per unit length of the wire before stranding shall be no more than 2 % greater than the nominal value given in tables 1 and 2, as appropriate.2 BSI 1997 BS 7884 : 1997 4.2.3 Stranded conductors The construction of the stranded conductors (i.e. the number of strands and the wi
28、re diameter) shall conform to tables 3 and 4, as appropriate. The mass per unit length of the stranded conductor shall be no more than 2 % greater than the nominal value given in tables 3 and 4, as appropriate. NOTE 1. The mass of a stranded conductor is affected by the lay ratio. With the exception
29、 of the central core wire, all wires are longer than the conductor length and the increase in mass per unit length depends on the lay ratio employed (see annex B). NOTE 2. Information on the calculation of the increase in length of component wires due to stranding and on the calculation of the masse
30、s per unit length and resistance in tables 3 and 4 is given in annex B. 4.3 Mechanical properties 4.3.1 Tensile properties When tested in accordance with BS EN 10002-1, the tensile breaking load of the component wires before stranding shall conform to tables 1 and 2, as appropriate. The tensile brea
31、king load of the stranded conductors shall conform to tables 3 and 4 as appropriate. The tensile breaking load shall be determined either directly see a) or by approximation see b) and shall conform to tables 3 and 4, as appropriate. a) Test on the complete strand in accordance with BS EN 10002-1; b
32、) Test according to BS EN 10002-1, on each of the component wires before stranding. The breaking load of the complete strand shall be determined by multiplying the sum of the breaking loads of the individual wires by a factor of 0.92 for three and seven strand conductors or 0.90 for nineteen and thi
33、rty-seven strand conductors. NOTE. The tensile breaking load specified corresponds to the maximum force (F max ), as defined in BS EN 10002-1. If it is required to test component wires of a stranded conductor after stranding, the values for a conductor shall satisfy the following conditions: The ten
34、sile breaking load of an individual strand shall be not less than 92.5 % of the appropriate value given in tables 1 and 2. The average breaking load of all the wires in the conductor shall be not less than 94 % of the appropriate value given in tables 1 and 2. 4.3.2 Wrap properties Solid conductors
35、and component wires taken from stranded conductors, either of copper of less than 5.6 mm nominal diameter, or of copper alloy less than 3.5 mm nominal diameter, shall not break when subjected to the wrap test given in annex C. 4.4 Electrical resistance When tested in accordance with annex D, the ele
36、ctrical resistance of the conductors at 20 C shall not exceed the maxima given in tables 1 to 4. NOTE. These maxima have been calculated on the basis of a resistivity at 20 C of 0.017 77mVm for hard drawn high conductivity copper or a resistivity at 20 C of 0.021 55mVm for hard drawn copper alloy. T
37、hese figures correspond to conductivities of 97 % and 80 % IACS respectively. 4.5 Manufacture 4.5.1 Stranding The construction and lay ratio of the different layers of a stranded conductor shall conform to table 5. In all constructions, the successive layers shall have opposite directions of lay, th
38、e outermost layer being right-handed, unless otherwise specified by the purchaser (see A.1e). The wires in each layer shall be evenly and closely stranded around the underlying wire or wires. 4.5.2 Joins 4.5.2.1 Before stranding The wires used in the construction of the conductor shall be drawn in c
39、ontinuous lengths without joins, except those made in the drawing stock prior to drawing. 4.5.2.2 During stranding 4.5.2.2.1 Cold compression welding Joins in individual wires made by cold compression welding are permissible, but no two joins shall be less than 15 m apart in the completed stranded c
40、onductor. 4.5.2.2.2 Brazing or resistance welding For all conductors containing seven wires or less, see 4.5.2.2.1. For conductors containing more than seven wires, joins made by brazing or resistance welding are permissible as well as joins made by cold compression welding. However, no two joins of
41、 any type shall be less than 15 m apart in the completed stranded conductor. 4.5.3 Identification of material When requested by the purchaser, one wire in the outer layer of wires shall be tinned for identification purposes. 4.5.4 Surface condition The surface of a solid conductor, or of the compone
42、nt wires before stranding, shall be clean, smooth and free from harmful defects. 5 Rounding of results The results obtained from tests for chemical composition and tensile strength shall be rounded to the last place of figures specified as limits, by applying the rounding rule given in BS 1957. BSI
43、1997 3 BS 7884 : 1997 Table 1. Physical, mechanical and electrical properties of solid, circular, hard drawn copper wire Nominal area of cross- section Wire diameter Nominal mass per unit length Resistance at 20 C Minimum breaking load Nominal Max. Min. mm 2 mm mm mm kg/km V/km V/km N 1.43 1.35 1.36
44、4 1.337 12.73 12.41 12.66 583 2.01 1.60 1.616 1.584 17.87 8.838 9.018 818 2.27 1.70 1.717 1.683 20.18 7.829 7.988 923 2.54 1.80 1.818 1.782 22.62 6.983 7.125 1035 3.46 2.10 2.121 2.079 30.79 5.130 5.235 1409 3.98 2.25 2.273 2.228 35.35 4.469 4.558 1618 4.75 2.46 2.484 2.435 42.25 3.739 3.816 1932 4.
45、91 2.50 2.525 2.475 43.64 3.620 3.694 1997 5.51 2.65 2.677 2.624 49.03 3.222 3.286 2244 6.16 2.80 2.828 2.772 54.74 2.886 2.944 2505 6.61 2.90 2.929 2.871 58.72 2.690 2.745 2687 7.07 3.00 3.030 2.970 62.84 2.514 2.565 2875 8.04 3.20 3.232 3.168 71.50 2.210 2.254 3271 9.90 3.55 3.586 3.515 87.99 1.79
46、5 1.831 4027 11.04 3.75 3.788 3.713 98.19 1.609 1.641 4494 14.52 4.30 4.350 4.250 129.1 1.224 1.253 5675 NOTE 1. Resistance values are calculated from a resistivity of 0.017 77mVm at 20 C. This is equivalent to a conductivity of 97 % IACS. Maximum values of resistance are calculated from minimum dia
47、meters. NOTE 2. Minimum breaking loads for nominal diameters up to and including 4 mm are based on the minimum diameter of conductor and a tensile strength of 415 N/mm 2 and for nominal diameters greater than 4 mm they are based on the minimum diameter of conductor and a tensile strength of 400 N/mm
48、 2 . NOTE 3. Nominal mass per unit length has been calculated using a density of 8890 kg/m 3 . Table 2. Physical, mechanical and electrical properties of solid, circular, hard drawn copper alloy wire Nominal area of cross- section Wire diameter Nominal mass per unit length Resistance at 20 C Minimum
49、 breaking load Nominal Max. Min. mm 2 mm mm mm kg/km V/km V/km N 2.27 1.70 1.717 1.683 20.30 9.494 9.687 1379 2.54 1.80 1.818 1.782 22.76 8.469 8.641 1546 3.14 2.00 2.020 1.980 28.10 6.860 6.999 1909 3.46 2.10 2.121 2.079 30.98 6.222 6.348 2105 3.98 2.25 2.273 2.228 35.57 5.420 5.527 2417 4.15 2.30 2.323 2.277 37.16 5.187 5.292 2525 4.91 2.50 2.525 2.475 43.91 4.390 4.479 2983 5.31 2.60 2.626 2.574 47.49 4.059 4.141 3226 6.16 2.80 2.828 2.772 55.08 3.500 3.571 3561 6.61 2.90 2.929 2.871 59.08 3.263 3.329 3820 8.04 3.20 3.232 3.168 71.94 2.680 2.734 4651 9.62 3.50
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