1、Designation: B787/B787M 04 (Reapproved 2014)Standard Specification for19 Wire Combination Unilay-Stranded Copper Conductorsfor Subsequent Insulation1This standard is issued under the fixed designation B787/B787M; the number immediately following the designation indicates the yearof original adoption
2、 or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval.A superscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This specification covers bare combination unilay-stranded conductors made f
3、rom round copper wires, eitheruncoated or coated with tin or lead alloy for insulated conduc-tors for electrical purposes. These conductors shall be con-structed with a central core wire surrounded by two layers ofhelically laid wires, resulting in an outer diameter equal to thecompressed-stranded e
4、quivalent conductor. (See ExplanatoryNote 1 and Note 2).NOTE 1For the purpose of this specification, combination unilayconductor is defined as follows: a central core wire surrounded by a layerof six helically laid wires of the same diameter as the core wire with ahelically laid outer layer containi
5、ng six smaller wires alternated betweensix wires of the same diameter as the wires in the layer underneath. Bothlayers have a common length and direction of lay (see Fig. 1).1.2 For the purpose of this specification, normal conductorclassification (Class AA, A, B, C) is not applicable as theseconduc
6、tors are intended for subsequent insulation.The descrip-tive term combination unilay-stranded shall be used in place ofconductor classification.1.3 The values stated in either SI units or inch-pound unitsare to be regarded separately as standard. The values stated ineach system may not be exact equi
7、valents; therefore, eachsystem shall be used independently of the other. Combiningvalues from the two systems may result in non-conformancewith the standard.1.3.1 For conductor sizes designated by AWG or kcmil, therequirements in SI units have been numerically converted fromcorresponding values, sta
8、ted or derived, in inch-pound units.1.3.2 For conductor sizes designated by SI units only, therequirements are stated or derived in SI units.1.3.3 For density, resistivity, and temperature, the valuesstated in SI units are to be regarded as standard.1.4 This standard does not purport to address all
9、of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 The following documents of the issue i
10、n effect on dateof material purchase form a part of this specification to theextent referenced herein.2.2 ASTM Standards:2B1 Specification for Hard-Drawn Copper WireB2 Specification for Medium-Hard-Drawn Copper WireB3 Specification for Soft or Annealed Copper WireB33 Specification for Tin-Coated Sof
11、t or Annealed CopperWire for Electrical PurposesB189 Specification for Lead-Coated and Lead-Alloy-CoatedSoft Copper Wire for Electrical PurposesB246 Specification for Tinned Hard-Drawn and Medium-Hard-Drawn Copper Wire for Electrical PurposesB263 Test Method for Determination of Cross-SectionalArea
12、of Stranded ConductorsB354 Terminology Relating to Uninsulated Metallic Electri-cal Conductors2.3 Other Standard:3NBS Handbook 100 Copper Wire Tables of the NationalBureau of Standards3. Ordering Information3.1 Orders for materials under this specification shall in-clude the following information:3.
13、1.1 Quantity of each size,3.1.2 Conductor Size: Circular-mil area or American WireGage, AWG (Section 7 and Table 1),3.1.3 Stranding (see Explanatory Note 3),3.1.4 Temper (see 4.2),3.1.5 Whether coated or uncoated; if coated, designate typeof coating (see 4.1 and 4.2),1This specification is under the
14、 jurisdiction of ASTM Committee B01 onElectrical Conductors and is the direct responsibility of Subcommittee B01.04 onConductors of Copper and Copper Alloys.Current edition approved Sept. 1, 2014. Published September 2014. Originallyapproved in 1988. Last previous edition approved in 2009 as B787/B7
15、87M 04(2009). DOI: 10.1520/B0787_B0787M-04R14.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from
16、 National Institute of Standards and Technology (NIST), 100Bureau Dr., Stop 1070, Gaithersburg, MD 20899-1070, http:/www.nist.gov.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.1.6 Details of special-purpose lays, if required (see
17、6.2),3.1.7 When physical tests shall be made (see 9.2 and 9.3),3.1.8 Package size (see 15.1),3.1.9 Lagging, if required (see 15.2),3.1.10 Special package marking, if required (Section 15),and3.1.11 Place of inspection (Section 13).4. Requirements for Wires4.1 The purchaser shall designate the type o
18、f wire and thekind of coating, if any, to be used in the conductor.4.2 Before stranding, the copper wire used shall meet all ofthe requirements of the followingASTM specifications that areapplicable to its type:4.2.1 Specification B3.4.2.2 Specification B33.4.2.3 Specification B2.4.2.4 Specification
19、 B1.4.2.5 Specification B189.4.2.6 Specification B246.4.3 In combination unilay stranded conductors, the centralcore wire shall be made of the same type and temper as thelayers, unless otherwise specified.5. Joints5.1 Welds and brazes may be made in rods or in wires priorto final drawing. Welds and
20、brazes may be made in the finishedindividual wires composing the conductor, but shall not becloser together than 50 ft (15.24 m) for hard and medium-hardconductors, and 1 ft in a layer for soft conductors.6. Lay6.1 For combination unilay conductors the lay of a layer ofwires shall be not less than 8
21、 nor more than 16 times theoutside diameter of the outer layer.6.2 Other lays for special purposes shall be furnished byspecial agreement between the manufacturer and the purchaser(Explanatory Note 4).6.3 The direction of lay shall be left-hand unless thedirection of lay is specified otherwise by th
22、e purchaser.7. Construction (Explanatory Note 3)7.1 The cross-sectional areas, numbers, and diameters ofwires in the various conductors shall conform to the require-ments prescribed in Table 1.7.2 The diameters of the wires listed in Table 2 are nominal.In order to produce an essentially round 19-wi
23、re construction,the outer 12-wire layer in the combination unilay product iscomprised of 6 wires of the same diameter as the wires in the7-wire core, and 6 wires approximately 25 % smaller. The2-wire sizes are alternated around the 7-wire core (Fig. 1).8. Physical and Electrical Tests of Conductors
24、Strandedof Soft Wires8.1 Tests for the electrical properties of wires composingconductors made from soft or annealed copper wire, bare orcoated, shall be made before stranding.8.2 Tests for the physical properties of soft or annealedcopper wire, bare or coated, may be made upon the wiresbefore stran
25、ding or upon wires removed from the completestranded conductor, but need not be made upon both. Care shallbe taken to avoid mechanical injury to wire removed from theconductor for the purpose of testing.8.3 The physical properties of wire when tested beforestranding shall conform to the applicable r
26、equirements of 4.2.8.4 The physical properties of wires removed from thecompleted stranded conductor shall be permitted to vary fromthe applicable requirements of 4.2 by the amounts as follows(Explanatory Note 5):8.4.1 Average of Results Obtained on All Wires TestedTheminimum elongation required sha
27、ll be reduced in numericalvalue 5 (for example, from 30 to 25 %) from the numericalrequirements for the wire before stranding.FIG. 1 Cross Section of ConductorTABLE 1 Construction Requirements for 19-Wire CombinationUnilay Stranded Copper ConductorsCross-Sectional AreaSize, American (orBrown andShar
28、pe)Wire D1ADiameter,Wire D2BDiameter,cmil sq mm Wire Gage mils mm mils mm500 000 253.4 175.6 4.5 128.5 3.3450 000 228.0 166.6 4.2 121.9 3.1400 000 202.7 157.1 4.0 115.0 2.9350 000 177.3 146.9 3.7 107.5 2.7300 000 152.0 136.0 3.5 99.6 2.5250 000 126.7 124.2 3.2 90.9 2.3211 600 107.2 0000 114.2 2.4 83
29、.6 2.1167 800 85.0 000 101.7 2.6 74.5 1.9133 100 67.4 00 90.6 2.3 66.3 1.7105 600 53.5 0 80.7 2.0 59.1 1.583 690 42.4 1 71.8 1.8 52.6 1.366 360 33.6 2 64.0 1.6 46.8 1.252 620 26.7 3 57.0 1.4 41.7 1.141 740 21.1 4 50.7 1.3 37.1 0.933 090 16.8 5 45.2 1.1 33.1 0.826 240 13.3 6 40.2 1.0 29.4 0.720 820 1
30、0.5 7 35.8 0.9 26.2 0.716 510 8.4 8 31.9 0.8 23.4 0.613 090 6.6 9 28.4 0.7 20.8 0.510 380 5.3 10 25.3 0.6 18.5 0.56530 3.3 12 20.1 0.5 14.7 0.44110 2.1 14 15.9 0.4 11.7 0.32580 1.3 16 12.6 0.3 9.2 0.21620 0.8 18 10.0 0.3 7.3 0.21020 0.5 20 7.9 0.2 5.8 0.1640 0.3 22 6.3 0.2 4.6 0.1404 0.2 24 5.0 0.1
31、3.7 0.1AEquation to calculate D1:Cross2 Sectional Area16.2149BEquation to calculate D2: D1 0.732.B787/B787M 04 (2014)28.4.2 Results Obtained on Individual WiresThe elongationof individual wires shall be reduced in numerical value 15 fromthe minimum requirements before stranding (that is, 10 inadditi
32、on to the 5 allowed in 8.4.1), but in no case shall theelongation of any individual wire be less than 5 %.8.5 In the event that the requirements prescribed in 8.4.2 aremet but those prescribed in 8.4.1 are not met, a retest shall bepermitted wherein all wires of the conductor shall be tested forthe
33、purpose of final determination of conformance to 8.4.8.6 Elongation tests to determine compliance shall not bemade on the conductor as a unit.8.7 If a tinning or lead-alloy-coating test is required, it shallbe made on the wires prior to stranding.9. Physical and Electrical Tests of Conductors Strand
34、edof Hard-Drawn or Medium-Hard Drawn Wires9.1 Tests for the physical and electrical properties of wirescomposing conductors made from hard-drawn or medium-hard-drawn wires, uncoated or coated, shall be made before butnot after stranding.9.2 At the option of the purchaser, tension and elongationtests
35、 on hard-drawn and medium-hard-drawn wires, uncoatedor coated, before stranding may be waived, and the completedhard-drawn and medium-hard-drawn conductors may be testedas a unit.The breaking strength of the bare conductors so testedshall be at least 90 % of the total of the specified minimumbreakin
36、g strengths of the component wires. The maximumbreaking strength of conductors made from medium-hard-drawn wires, uncoated or coated, shall be not greater than thesum of the specified maximum breaking strengths of thecomponent wires. The minimum breaking strengths of wiresshall be calculated using s
37、pecified nominal diameters andspecified minimum tensile strengths. The maximum breakingstrengths of wires shall be calculated using nominal diametersand specified maximum tensile strengths. The free lengthbetween grips of the test specimen shall be not less than 24 in.(610 mm), and care shall be tak
38、en to ensure that the wires inthe conductor are evenly gripped during the test (ExplanatoryNote 6).9.3 When requested by the purchaser at the time of placingthe order, tension tests on hard-drawn and medium-hard-drawnwires, uncoated or coated, before stranding or as a unit may bewaived and tests mad
39、e on wires removed from the completedconductor. The test limits, based on a 10-in. (254-mm) gagelength, for such tests shall be specified by the purchaser in theplacing of individual orders (Explanatory Note 5).9.4 If a tinning test is required, it shall be made on the wiresprior to stranding.10. De
40、nsity10.1 For the purpose of calculating masses, cross sections,and so forth, the density of the copper shall be taken as 8.89g/cm3(0.32117 lb/in.3) at 20C (Explanatory Note 7).11. Mass and Resistance11.1 The mass and electrical resistance of a unit length ofstranded conductor are a function of the
41、length of lay. Theapproximate mass and electrical resistance may be determinedusing the standard increment of 2 %. When greater accuracy isTABLE 2 Diameters, Areas, and Masses of 19-Wire Combination Unilay Stranded Copper ConductorsNominal Area MassSize of Conductorcmil or AWG sq mm Nominal Diameter
42、, in.AConductor, mm in.2mm2lbs/1000 ft lbs/mile g/m500 000 253.4 0.784 19.914 0.392700 253.35 1544 8151 2297450 000 228.0 0.744 18.878 0.353400 228.02 1389 7336 2067400 000 202.7 0.701 17.805 0.314000 202.68 1235 6521 1838350 000 177.3 0.656 16.662 0.274900 177.35 1081 5706 1609300 000 152.0 0.607 1
43、5.418 0.235600 152.01 926.3 4891 1378250 000 126.7 0.554 14.072 0.196300 126.68 771.9 4076 11490000 107.2 0.510 12.954 0.166200 107.22 653.3 3450 972.1000 85.0 0.454 11.532 0.131800 85.02 518.1 2736 770.900 67.4 0.404 10.262 0.104500 67.44 410.9 2169 611.40 53.5 0.360 9.144 0.082910 53.51 325.8 1720
44、 684.81 42.4 0.321 8.153 0.065730 42.41 258.4 1364 384.52 33.6 0.286 7.264 0.052120 33.62 204.9 1082 304.93 26.7 0.254 6.452 0.041330 26.77 162.5 858.1 241.84 21.1 0.226 5.740 0.032780 21.15 128.9 680.5 191.85 16.8 0.202 5.131 0.025990 16.77 102.2 539.6 152.16 13.3 0.179 4.547 0.020610 13.30 81.05 4
45、28.0 120.67 15.6 0.160 4.064 0.016350 10.55 64.28 339.4 95.658 8.4 0.143 3.632 0.012970 8.37 50.97 269.1 75.849 6.6 0.127 3.226 0.010280 6.63 40.42 213.4 60.1410 5.3 0.113 2.870 0.008155 5.26 32.06 169.3 47.7112 3.3 0.090 2.286 0.005130 3.31 20.16 106.5 30.0014 2.1 0.071 1.803 0.003230 2.08 12.68 66
46、.95 18.8716 1.3 0.056 1.422 0.002030 1.31 7.974 42.10 11.8718 0.8 0.045 1.143 0.001280 0.82 5.015 26.48 7.46220 0.5 0.035 0.809 0.000804 0.52 3.154 16.65 4.69322 0.3 0.028 0.703 0.000503 0.32 1.992 10.52 2.96424 0.2 0.022 0.558 0.000317 0.20 1.249 6.59 1.859ATo calculate the diameter, multiply the l
47、arge wire diameter in Table 1 by 3 and add two times the small wire diameter.Example: AWG 4/0 diameter = (3(114.2) + 2 (83.6) = 509.8B787/B787M 04 (2014)3desired, the increment based on the specific lay of the conduc-tor may be calculated (Explanatory Note 8).12. Variance in Area12.1 The cross-secti
48、onal area of the completed conductorshall be not less than 98 % of the area indicated in Column 1of Table 1. Unless otherwise specified by the purchaser, themanufacturer shall determine the cross-sectional area by thefollowing method:12.1.1 The cross-sectional area of a conductor may bedetermined by
49、 Test Method B263. In applying this method, theincrement in mass resulting from stranding may be the appli-cable value specified in 11.1 or may be calculated from themeasured component dimensions of the sample under test. Incase of question regarding area compliance, the actual massincrement due to stranding shall be calculated.13. Inspection13.1 Unless otherwise specified in the contract or purchaseorder, the manufacturer shall be responsible for the perfor-mance of all inspection and test requirements specified.13.2 All inspections and tests shall be made at the place o
