1、Designation: B 193 02 (Reapproved 2008)Standard Test Method forResistivity of Electrical Conductor Materials1This standard is issued under the fixed designation B 193; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of las
2、t revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1. Scope1.1 This test method covers the determinatio
3、n of the elec-trical resistivity of metallic electrical conductor material. Itprovides for an accuracy of 60.30 % on test specimens havinga resistance of 0.00001 V (10 V) or more. Weight resistivityaccuracy may be adversely affected by possible inaccuracies inthe assumed density of the conductor.1.2
4、 This standard does not purport to address all 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 Docu
5、ments2.1 ASTM Standards:2A 111 Specification for Zinc-Coated (Galvanized) “Iron”Telephone and Telegraph Line WireA 326 Specification for Zinc-Coated (Galvanized) HighTensile Steel Telephone and Telegraph Line Wire3B9 Specification for Bronze Trolley WireB 105 Specification for Hard-Drawn Copper Allo
6、y Wiresfor Electric ConductorsB 298 Specification for Silver-Coated Soft or AnnealedCopper WireB 355 Specification for Nickel-Coated Soft or AnnealedCopper WireB 415 Specification for Hard-Drawn Aluminum-Clad SteelWireB 566 Specification for Copper-Clad Aluminum WireB 800 Specification for 8000 Seri
7、es Aluminum Alloy Wirefor Electrical PurposesAnnealed and Intermediate Tem-pers2.2 NIST Document:NBS Handbook 100 Copper Wire Tables43. Resistivity3.1 Resistivity (Explanatory Note 1) is the electrical resis-tance of a body of unit length, and unit cross-sectional area orunit weight.3.2 Volume Resis
8、tivity is commonly expressed in ohms fora theoretical conductor of unit length and cross-sectional area;in inch-pound units in Vcmil/ft and in acceptable metric unitsin Vmm2/m. It may be calculated by the following equation:rv5 A/L!Rwhere:rv= volume resistivity, Vcmil/ft or Vmm2/m,A = cross-sectiona
9、l area, cmil or mm2,L = gage length, used to determine R,ftorm,andR = measured resistance, V.3.3 Weight Resistivity is commonly expressed in ohms for atheoretical conductor of unit length and weight. The methodfor calculating weight resistivity, based on resistance, length,and weight measurements, o
10、f a test specimen is given inExplanatory Note 2.4. Apparatus4.1 Resistance shall be measured with a circuit configura-tion and instrumentation that has a resistance measurementcapability of 60.15 % accuracy.5. Test Specimen5.1 The test specimen may be in the form of a wire, strip,rod, bar, tube, or
11、shape. It shall be of uniform cross sectionthroughout its length within 60.75 % of the cross-sectionalarea. Wherever possible it shall be the full cross section of thematerial it represents, if the full cross section is such that theuniformity of the cross-sectional area can be accurately deter-mine
12、d.5.2 The test specimen shall have the following characteris-tics:5.2.1 A resistance of at least 0.00001 V (10 V) in the testlength between potential contacts,1This test method is under the jurisdiction of ASTM Committee B01 onElectrical Conductors and is the direct responsibility of Subcommittee B0
13、1.02 onMethods of Test and Sampling Procedure.Current edition approved Sept. 1, 2008. Published September 2008. Originallyapproved in 1944. Last previous edition approved in 2002 as B 193 02.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serv
14、iceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Withdrawn4Available from National Institute of Standards and Technology (NIST), 100Bureau Dr., Stop 1070, Gaithersburg, MD 20899-1070, http:/www.nist.gov.1Copyright ASTM
15、 International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5.2.2 A test length of at least 1 ft or 300 mm,5.2.3 A diameter, thickness, width, or other dimensionsuitable to the limitations of the resistance measuring instru-ment,5.2.4 No surface cracks or defe
16、cts visible to the unaidednormal eye, and substantially free from surface oxide, dirt, andgrease, and5.2.5 No joints or splices.6. Procedure6.1 Make all determinations of the dimensions and weightof the test specimen using instruments accurate to 60.05 %. Inorder to assure this accuracy in measuring
17、 the length betweenpotential contacts, the surface in contact with the test specimenshall be a substantially sharp knife-edge when using a Kelvin-type bridge or a potentiometer.6.2 The cross-sectional dimensions of the specimen may bedetermined by micrometer measurements, and a sufficientnumber of m
18、easurements shall be made to obtain the meancross section to within 60.10 %. In case any dimension of thespecimen is less than 0.100 in. and cannot be measured to therequired accuracy, determine the cross-section from the weight,density, and length of the specimen.6.3 When the density is unknown, de
19、termine the density byweighing a specimen first in air and then in a liquid of knowndensity at the test temperature, which shall be room tempera-ture to avoid errors due to convection currents. Exercise care inremoving all air bubbles from the specimen when weighing itin the liquid. Calculate the de
20、nsity from the following equa-tion:d5Wa3 d!/Wa2 Wl!where:d = density of the specimen, g/cm3;Wa= weight of the specimen in air, g;Wl= weight of the specimen in the liquid, g; andd = density of the liquid at the test temperature, g/cm3.6.4 When potential leads are used, make sure the distancebetween e
21、ach potential contact and the corresponding currentcontact is at least equal to 112 times the cross-sectionalperimeter of the specimen. Make sure the yoke resistance(between reference standard and test specimen) is appreciablysmaller than that of either the reference standard or the testspecimen unl
22、ess a suitable lead compensation method is used,or it is known that the coil and lead ratios are sufficientlybalanced so that variation in yoke resistance will not decreasethe bridge accuracy below stated requirements.6.5 Make resistance measurements to an accuracy of60.15 %. To ensure a correct rea
23、ding, allow the referencestandard and the test specimen to come to the same temperatureas the surrounding medium. (If the reference standard is madeof manganin it is possible to obtain correct readings with thetest specimen at reference temperatures other than roomtemperature). In all resistance mea
24、surements, the measuringcurrent raises the temperature of the medium. Therefore, takecare to keep the magnitude of the current low, and the time ofits use short enough so that the change in resistance cannot bedetected with the galvanometer. To eliminate errors due tocontact potential, take two read
25、ings, one direct and one withcurrent reversed, in direct succession. Check tests are recom-mended whereby the specimen is turned end for end, and thetest repeated. Surface cleaning of the specimen at current andpotential contact points may be necessary to obtain goodelectrical contact.7. Temperature
26、 Correction7.1 When the measurement is made at any other than areference temperature, the resistance may be corrected formoderate temperature differences to what it would be at thereference temperature, as follows:RT5Rt1 1aTt T!where:RT= resistance at reference temperature T,Rt= resistance as measur
27、ed at temperature t,aT= known or given temperature coefficient of resistanceof the specimen being measured at reference tempera-ture T,T = reference temperature, andt = temperature at which measurement is made.NOTE 1The parameter aT, in the above equation, varies with conduc-tivity and temperature.
28、For copper of 100 % conductivity and a referencetemperature of 20C, its value is 0.00393. Values at other conductivitiesand temperatures will be found in NBS Handbook 100.4Table 1 liststemperature coefficients for the common electrical conductor materials.8. Report8.1 For referee tests, report the f
29、ollowing information:8.1.1 Identification of test specimen,8.1.2 Kind of material,8.1.3 Test temperature,8.1.4 Test length of specimen,8.1.5 Method of obtaining cross-sectional area:8.1.5.1 If by micrometer, the average values of micrometerreadings, or8.1.5.2 If by weighing, a record of length, weig
30、ht, anydensity determinations that may be made, and calculatedcross-sectional areas.8.1.6 Weight, if used,8.1.7 Method of measuring resistance,8.1.8 Value of resistance,8.1.9 Reference temperature,8.1.10 Calculated value of resistivity at the reference tem-perature, and8.1.11 Previous mechanical and
31、 thermal treatments. (Sincethe resistivity of a material usually depends upon them, theseshall be stated whenever the information is available.)8.2 For routine tests, only such of the items in 8.1 as applyto the particular case, or are significant, shall be reported.9. Precision and Bias9.1 Precisio
32、nThis test method has been in use for manyyears. No statement of precision has been made and no workhas been planned to develop such a statement.9.2 BiasThis test method has no bias because the valuefor resistivity is determined solely in terms of this test method.B 193 02 (2008)210. Keywords10.1 co
33、nductivity; electrical conductor materials; resistivity;resistivity of electrical conductor; volume resistivity; weightresistivityEXPLANATORY NOTESNOTE 1Volume resistivity is used in place of “weight resistivity” and“percent conductivity.”Resistivity units are based on the International Annealed Cop
34、perStandard (IACS) adopted by IEC in 1913, which is 1/58 Vmm2/m at 20C(68F) for 100 % conductivity. The value of 0.017241 Vmm2/m and thevalue of 0.15328 Vg/m2at 20C (68F) are respectively the internationalequivalent of volume and weight resistivity of annealed copper equal (tofive significant figure
35、s) to 100 % conductivity. The latter term means thata copper wire1minlength and weighing 1 g would have a resistance of0.15328 V. This is equivalent to a resistivity value of 875.20 Vlb/mile2,which signifies the resistance of a copper wire 1 mile in length weighing1 lb. It is also equivalent, for ex
36、ample, to 1.7241 V/cm of length of acopper bar 1 cm2in cross section. A complete discussion of this subject iscontained in NBS Handbook 100.4The use of five significant figures inexpressing resistivity does not imply the need for greater accuracy ofmeasurement than that specified in Test Method B 19
37、3. The use of fivesignificant figures is required for reasonably accurate reversible conver-sion from one set of resistivity units to another. The equivalent resistivityvalues in Table 3 were derived from the fundamental IEC value (1/58Vmm2/m) computed to seven significant figures and then rounded t
38、o fivesignificant figures.NOTE 2Weight resistivity is expressed in U.S. customary units inVlb/mile2and in metric units in Vg/m2. It may be calculated as follows:rw5 W/L1L2!Rwhere:rw= weight resistivity, Vlb/mile2or Vg/m2,W = weight of the test specimen, lb or g,L2= length of the test specimen, miles
39、 or m,L1= gage length, used to determine R, miles or m, andR = measured resistance, VNOTE 3Resistivity and Conductivity ConversionConversion of thevarious units of volume resistivity, weight resistivity, and conductivity,may be facilitated by employing the formulas and factors shown in Table1. The f
40、actors given therein are applicable to all metallic electricalconductor material. Table 2 lists values of density, d, for the commonelectrical conductor materials.NOTE 4DensityFor the purpose of resistivity and conductivityconversion, the density of the various conductor materials may be taken assho
41、wn in Table 2, based on a temperature of 20C (68F).However, if the conversion is for specification acceptance purposes, thedensity used shall be that specified in the product specification involved.TABLE 1 Resistivity and Conductivity ConversionNOTE 1These factors are applicable only to resistivity
42、and conductivity values corrected to 20C (68F). They are applicable for any temperaturewhen used to convert between volume units only or between weight units only. Values of density, d, for the common electrical conductor materials, arelisted in Table 2.Given NPerform indicatedoperation to obtain Vo
43、lume Resistivity at 20C Weight Resistivity at 20C Conductivity at 20CVcmil/ft Vmm2/m Vin. Vcm Vlb/mile2Vg/m2% IACS(Volume Basis)% IACS(Weight Basis)Volume Resistivity at 20CVcmil/ft . . . N 3 601.52 N 3 15.279 N 3 6.0153 N 3 0.10535 3(l / d)N 3 601.53 3(l / d)(l /N) 3 1037.1 (l /N) 3 9220.03 (l / d)
44、Vmm2/m N 3 0.0016624 . . . N 3 0.025400 N 3 0.010000 N 3 0.000175133 (l / d)N 3 (l /d) (l /N) 3 1.7241 (l /N) 3 15.3283 (l / d)Vin. N 3 0.065450 N 3 39.370 . . . N 3 0.39370 N 3 0.00689503 (l / d)N 3 39.370 3(l /d)(l /N) 3 67.879 (l /N) 3 603.453 (l / d)Vcm N 3 0.16624 N 3 100.00 N 3 2.5400 . . . N
45、3 0.017513 3(l / d)N 3 100.00 3(l / d)(l /N) 3 172.41 (l /N) 3 1532.83 (l / d)Weight Resistivity at 20CVlb/mile2N 3 9.4924 3d N 3 5710.0 3d N 3 145.03 3d N 3 57.100 3d . N 3 5710.0 (l /N) 3 9844.83d(l /N) 3 87520Vg/m2N 3 0.00166243dN 3d N 3 0.0254003dN 3 0.0100003dN 3 0.00017513 . . . (l/N) 3 1.7241
46、3d(l /N) 3 15.328Conductivity at 20C% IACS (volume basis) (l /N) 3 1037.1 (l /N) 3 1.7241 (l /N) 3 67.879 (l /N) 3 172.41 (l /N) 3 9844.83d(l /N) 3 1.72413d. N 3 0.112493d% IACS (weight basis) (l /N) 3 9220.03 (l / d)(l /N) 3 15.3283 (l / d)(l /N) 3 603.453 (l / d)(l /N) 3 1532.83 (l / d)(l /N) 3 87
47、520 (l /N) 3 15.328 N 8.89 3 (l /d) .B 193 02 (2008)3TABLE 2 Density and Temperature Coefficient of Resistance for Electrical Conductor MaterialsMaterialApproximate Density,d, at 20C, g/cm3TemperatureCoefficient ofResistance, a,at20CMaterialApproximate Density,d, at 20C, g/cm3TemperatureCoefficient
48、ofResistance, a,at20CCopper, % IACS: Aluminum Alloy 8000,101 8.89 0.00397 Specification B 800, % IACS:100 8.89 0.00393 61.8 2.71 0.0040898.40 8.89 0.00387 61.5 2.71 0.0040698.16 8.89 0.00386 61.4 2.71 0.0040697.80 8.89 0.00384 61.3 2.71 0.0040597.66 8.89 0.00384 61.2 2.71 0.0040497.40 8.89 0.00383 6
49、1.0 2.71 0.0040397.16 8.89 0.00382 60.9 2.71 0.0040296.66 8.89 0.00380 60.8 2.71 0.0040296.16 8.89 0.00378 60.7 2.71 0.0040194.16 8.89 0.00370 60.6 2.71 0.0040093.15 8.89 0.00366Aluminum Alloy 6101,Silver Coated Copper, % IACS:Specification B 298: 59.5 2.70 0.00393Class A 8.91 0.00393 59.0 2.70 0.00390Class B 8.93 0.00393 57.0 2.70 0.00377Class C 8.95 0.00394 56.5 2.70 0.00373Class D 8.99 0.00394 56.0 2.70 0.00370Class E 9.05 0.00395 55.0 2.70 0.0036354.0 2.70 0.00357Nickel Coated Copper, 53.0 2.70 0.00350Sp
