1、Designation: B 786 08Standard Specification for19 Wire Combination Unilay-Stranded AluminumConductors for Subsequent Insulation1This standard is issued under the fixed designation B 786; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revisi
2、on, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This specification covers bare combination unilay-stranded conductors made from round wires of aluminu
3、m 1350and 8000 series of aluminum alloys, for insulated conductorsfor electrical purposes. Aluminum 1350 wires in tempers -H19(extra hard), -H16 or -H26 (34 hard), -H14 or -H24 (12 hard),and -H142 or -H242 (12 hard) and 8000 series aluminum alloyswires in tempers “0” and H1X or H2X are permitted. Th
4、eseconductors shall be constructed with a central core wiresurrounded by two layers of helically laid wires, resulting in anouter diameter equal to the compressed-stranded equivalentconductors.NOTE 1For the purpose of this specification, combination unilayconductor is defined as follows: a central c
5、ore wire surrounded by a layerof six helically laid wires of the same diameter as the core wire with ahelically laid outer layer containing 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 (s
6、ee Fig. 1).1.1.1 For the purpose of this specification, normal conductorclassification (Class AA, A, B, C) is not applicable, as theseconductors are intended for subsequent insulation.The descrip-tive term combination unilay-stranded shall be used in place ofconductor classification (Note 2 and Note
7、 3).NOTE 2Prior to 1975, aluminum 1350 was designated as EC alumi-num.NOTE 3The aluminum and temper designations conform to ANSIStandard H35.1. Aluminum 1350 corresponds to Unified NumberingSystem A91350 in accordance with Practice E 527. Unified NumberingSystem alloy designations for 8000 Series al
8、uminum alloys in accordancewith Practice E 527 are listed in Table number 1 of Specification B 800.1.2 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 equivalents; therefore, eachsystem shall be used
9、independently of the other. Combiningvalues from the two systems may result in non-conformancewith the standard.2. Referenced Documents2.1 The following documents of the issue in effect on dateof material purchase form a part of this specification to theextent referenced herein.2.2 ASTM Standards:2B
10、 193 Test Method for Resistivity of Electrical ConductorMaterialsB 230/B 230M Specification for Aluminum 1350H19Wire for Electrical PurposesB 263 Test Method for Determination of Cross-SectionalArea of Stranded ConductorsB 609/B 609M Specification for Aluminum 1350 RoundWire, Annealed and Intermedia
11、te Tempers, for ElectricalPurposesB 800 Specification for 8000 Series Aluminum Alloy Wirefor Electrical PurposesAnnealed and Intermediate Tem-persB 801 Specification for Concentric-Lay-Stranded Conduc-tors of 8000 Series Aluminum Alloy for SubsequentCovering or InsulationE29 Practice for Using Signi
12、ficant Digits in Test Data toDetermine Conformance with SpecificationsE 527 Practice for Numbering Metals and Alloys in theUnified Numbering System (UNS)2.3 ANSI Standard:ANSI H35.1/H35.1(M) Alloy and Temper Designation Sys-tems for Aluminum32.4 NIST Standard:NBS Handbook 10043. Ordering Information
13、3.1 Orders for materials under this specification shall in-clude the following information:3.1.1 Conductor alloy,1This specification is under the jurisdiction of ASTM Committee B01 onElectrical Conductors and is the direct responsibility of Subcommittee B01.07 onConductors of Light Metals.Current ed
14、ition approved Sept. 1, 2008. Published October 2008. Originallyapproved in 1988. Last previous edition approved in 2002 as B 786 02a.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume info
15、rmation, refer to the standards Document Summary page onthe ASTM website.3Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.4Available from National Institute of Standards and Technology (NIST), 100Bureau Dr., Stop 1070, Gai
16、thersburg, MD 20899-1070, http:/www.nist.gov.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.1.2 Quantity of each size,3.1.3 Conductor size: Circular-mil area or American WireGage, AWG (Section 6 and Table 1),3.1.4 Stranding (see E
17、xplanatory Note 1),3.1.5 Temper (see Section 11),3.1.6 Details of special-purpose lays, if required (see 5.2),3.1.7 When physical tests shall be made (see Sections 7 and8),3.1.8 Package size (see 16.1),3.1.9 Heavy wood lagging, if required (see 17.2),3.1.10 Special package marking, if required (Sect
18、ion 17),and3.1.11 Place of inspection (Section 15).4. Joints4.1 Electric-butt welds, cold pressure welds, or electric-buttcold-upset welds may be made in the finished individual wirescomposing the conductor but shall not be closer together than1 ft (Explanatory Note 2).5. Lay5.1 For combination unil
19、ay conductors the lay of a layer ofwires shall be not less than 8 nor more than 16 times theoutside diameter of the outer layer.5.2 Other lays for special purposes shall be furnished byspecial agreement between the manufacturer and the purchaser.NOTE 4Certain types of insulation conductors may requi
20、re shorter laythan other conductors. It is expected that special requirements regardinglength of lay will be specified by the purchaser in such instances.5.3 The direction of lay shall be left-hand unless thedirection of lay is specified otherwise by the purchaser.6. Construction (Explanatory Note 1
21、)6.1 The areas of cross section, numbers, and diameters ofwires in the various conductors shall conform to the require-ments prescribed in Table 1 (Note 3) (see Fig. 1).6.2 The diameters of the wires listed in Table 2 are nominal.In order to produce an essentially round 19-wire construction,the oute
22、r 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.7. Mechanical and Electrical Tests of Conductors notAnnealed after Stranding7.1
23、Wires composing the conductors shall be tested prior tostranding in accordance with the applicable specification (see11.1.2), and tests on the completed conductor are not required.However, when requested by the purchaser and agreed to bythe manufacturer at time of ordering, the tension tests of wire
24、sbefore stranding may be waived and the completed conductortested in accordance with 7.2, or wires removed from thecompleted conductor tested in accordance with 7.5.7.2 When the completed conductor is tested as a unit, thebreaking strength shall be not less than the rated strength of1350-H19 conduct
25、ors or the minimum rated strength of 1350-H16, -H26, -H14, -H24, -H142, and -H242 conductors iffailure occurs in the free length at least 1 in. (25 mm) beyondthe end of either gripping device. The strength shall be not lessthan 95 % of the rated or minimum rated strength if failureoccurs inside, or
26、within 1 in. of the end of either grippingdevice. The breaking strength of 1350-H16, -H26, -H14, -H24,-H142, and -H242 conductors shall be not greater than theirmaximum rated strengths. The free length between grips of thetest specimen shall be not less than 24 in. (600 mm) and careshall be taken to
27、 ensure that the wires in the conductor areevenly gripped during the test (Explanatory Note 3).7.3 The rated strength of 1350-H19 conductors and theminimum rated strength of 1350-H16, -H26, -H14, -H24,-H142, and -H242 conductors shall be taken as 93 % of thesum of the specified minimum average tensi
28、le strengths of thecomponent wires for 1350-H19 conductors, as prescribed inTable 1, Tensile Requirements, of Specification B 230/B 230M, and of the sum of the specified minimum tensilestrengths of the component wires for 1350-H16, -H26, -H14,-H24, -H142, and -H242 conductors, as prescribed in Speci
29、fi-cation B 609/B 609M, as applicable. The maximum ratedstrength of the 1350-H16, -H26, -H14, -H24, -H142 and -H242FIG. 1 Cross Section of ConductorTABLE 1 Construction Requirements for 19-Wire CombinationUnilay Stranded Aluminum ConductorsArea ofCross-Section,cmilSize, American (orBrown and Sharpe)
30、Wire GageWire D1ADiameterWire D2BDiametermils mm mils mm556 500 185.3 4.71 135.6 3.44500 000 175.6 4.46 128.5 3.26477 000 171.5 4.36 125.5 3.19450 000 166.6 4.23 121.9 3.10397 500 156.6 3.98 114.6 2.91350 000 146.9 3.73 107.5 2.73336 400 144.0 3.66 105.4 2.68300 000 136.0 3.45 99.6 2.53266 800 128.3
31、 3.26 93.9 2.38250 000 124.2 3.15 90.9 2.31211 600 0000 114.2 2.90 83.6 2.12167 800 000 101.7 2.58 74.5 1.89133 100 00 90.6 2.30 66.3 1.68105 600 0 80.7 2.05 59.1 1.5083 690 1 71.8 1.82 52.6 1.3466 360 2 64.0 1.63 46.8 1.1952 620 3 57.0 1.45 41.7 1.0641 740 4 50.7 1.29 37.1 0.9433 090 5 45.2 1.15 33
32、.1 0.8426 240 6 40.2 1.02 29.4 0.7520 820 7 35.8 0.91 26.2 0.6716 510 8 31.9 0.81 23.4 0.5913 090 9 28.4 0.72 20.8 0.5310 380 10 25.3 0.64 18.5 0.476 530 12 20.1 0.51 14.7 0.37AEquation to calculate D1:D15Cross2Sectional Area16.2149BEquation to calculate D2:D25 D13 0.732.B786082conductors shall be t
33、aken as the sum of the specified maximumstrengths of the component wires, as prescribed in Specifica-tion B 609/B 609M, as applicable. The rated strengths shall becalculated using specified nominal wire diameters.7.4 Rated strength and breaking strength values shall berounded to three significant fi
34、gures, in the final value only, inaccordance with the rounding method in Practice E29.7.5 When wires are removed from the completed conductorand tested, 1350-H19 wires shall have minimum tensilestrengths not less than 95 % of the tensile strengths prescribedfor individual tests in Table 1, Tensile R
35、equirements, ofSpecification B 230/B 230M. 1350-H16, -H26, -H14, -H24,-H142, and -H242 wires shall have tensile strengths not lessthan 95 % of the minimum tensile strength nor more than105 % of the maximum tensile strength prescribed in Specifi-cation B 609/B 609M, as applicable (Explanatory Note 4)
36、.7.6 All wires composing the conductors shall be capable ofmeeting the bending properties stated in Specification B 230/B 230M after stranding. Routine production testing afterstranding is not required.7.7 Mechanical and electrical tests of conductors in 8000series aluminum alloys in “0” temper, H1X
37、 or H2X wire andnot annealed after stranding shall be in accordance withSection 9 of Specification B 801.8. Mechanical and Electrical Tests of ConductorsAnnealed after Stranding8.1 Tensile properties and electrical resistivity shall bedetermined on samples taken from 10 % of the reels or coils ofcon
38、ductor, but from not less than five (or all if the lot is lessthan five) reels or coils. Resistivity shall be determined asprescribed in the Resistivity section of Specification B 230/B 230M on one wire from each conductor sample except thistest is not required if performed previously on the 1350-H1
39、9wire. At the manufacturers option, tension tests shall be madeeither on one of the inner seven wires and one wire from eachadditional layer of each conductor sample to determine con-formance with 8.2 or on the conductor as a unit to determineconformation with 8.3.8.2 When wires removed from the com
40、pleted conductor aretested, 1350-H26, -H24, and -H242 wires shall have tensilestrengths not less than 95 % of the minimum tensile strengthnor more than 105 % of the maximum tensile strength pre-scribed in Specification B 609/B 609M, as applicable (Ex-planatory Note 4).8.3 When the completed conducto
41、r is tested as a unit, thebreaking strengths of 1350-H26, -H24, and -H242 conductorsshall conform with 7.2, 7.3, and 7.4.8.4 All wires composing the conductors shall be capable ofmeeting the bending properties stated in Specification B 230/B 230M after stranding. Routine production testing afterstra
42、nding is not required.8.5 Mechanical and electrical tests of conductors of 8000series aluminum alloys fabricated from wires other than H2Xand annealed after stranding to meet “0” temper or H2Xrequirements shall be in accordance with Section 10 ofSpecification B 801.9. Mass and Resistance9.1 The mass
43、 and electrical resistance of a unit length ofstranded conductor are a function of the length of lay. Theapproximate mass and electrical resistance may be determinedTABLE 2 Diameters, Areas and Mass of 19-Wire Combination Unilay Stranded Aluminum ConductorASize ofConductor,cmil orAWGNominal Conducto
44、rDiameterBNominal Area MassDirect Current Resistanceat 20Cin. mm in.2mm2lb/1000 ft kg/km V/1000 ft V/km556 500 0.827 21.0 0.4371 282 521 775 0.0312 0.1024500 000 0.784 19.9 0.3927 253 468 697 0.0347 0.1139477 000 0.766 19.5 0.3746 242 447 665 0.0364 0.1194450 000 0.744 18.9 0.3534 228 421 627 0.0385
45、 0.1263397 500 0.699 17.8 0.3122 201 372 554 0.0436 0.1431350 000 0.656 16.7 0.2749 177 328 488 0.0495 0.1624336 400 0.643 16.3 0.2642 170 315 469 0.0516 0.1693300 000 0.607 15.4 0.2356 152 281 418 0.0578 0.1896266 800 0.573 14.6 0.2095 135 250 372 0.0650 0.2133250 000 0.554 14.1 0.1963 127 234 348
46、0.0694 0.22770000 0.510 13.0 0.1662 107 198 295 0.0820 0.2690000 0.454 11.5 0.1318 85.0 157 234 0.103 0.338900 0.404 10.3 0.1045 67.4 125 185 0.130 0.42750 0.360 9.14 0.08291 53.5 98.9 147 0.164 0.53871 0.321 8.15 0.06573 42.4 78.4 117 0.207 0.67982 0.286 7.26 0.05212 33.6 62.1 92.4 0.261 0.85733 0.
47、254 6.45 0.04133 26.7 49.3 73.4 0.330 1.08144 0.226 5.74 0.03278 21.1 39.1 58.2 0.416 1.36335 0.202 5.13 0.02599 16.8 31.0 46.1 0.523 1.726 0.179 4.55 0.02061 13.3 24.6 36.6 0.661 2.16847 0.160 4.06 0.01635 10.5 19.5 29.0 0.834 2.73628 0.143 3.63 0.01297 8.37 15.5 23.1 1.05 3.44649 0.127 3.23 0.0102
48、8 6.63 12.3 18.3 1.32 4.330710 0.113 2.87 0.00816 5.26 9.73 14.5 1.67 5.479012 0.090 2.29 0.00513 3.31 6.12 9.11 2.67 8.7598AMass and electrical resistance are based on aluminum 1350.BTo calculate the diameter, multiply the large wire diameter in Table 1 times 3 and add two times the small wire diam
49、eter.Example: AWG 4/0 diameter = 3(114.2) + 2(83.6) = 509.8B786083using the standard increment of 2 %. When greater accuracy isdesired, the increment based on the specific lay of the conduc-tor may be calculated (Explanatory Note 1).9.2 The maximum electrical resistance of a unit length ofstranded conductor shall not exceed 2 % over the nominal d-cresistance shown in Table 2 (Explanatory Note 6). When thed-c resistance is measured at other than 20C, it is to becorrected by using the multiplying factor given in Table 3.9.3 For conductors to be used in covered or insu
