ASTM B496-04 pdf free.Standard Specification for Compact Round Concentric-Lay-Stranded Copper Conductors.
The length of lay shall be not less than 8 nor more than16 times the outside diameter of the completed conductor.5.2 The direction of lay of the outer layer shall be lefthand,and it shall be reversed in successive layers,unidirectional,orunilay.The construction of the compact round concentric-lay-stranded conductors shall be as shown in Table 1.The starting round copper wires used in the fabricationof the compact round conductor shall be of such diameter as toproduce a finished conductor having a nominal cross-sectionalarea and diameter as prescribed in Table 1.
For the purpose of calculating linear densities，crosssections, and so forth, the density of the copper shall be takenas 8.89 g/cm3 (0.32117 lbl/in.3) at 20°C.The mass per unit length and dc electrical resistance ofa compact round conductor are greater than the total of thesecharacteristics of the compressed wires composing the finishedconductor, depending upon the lay.The standard increment ofmass per unit length and electrical resistance shall be taken as2 %.The nominal mass per unit length and dc resistance are shown in Table 1.When the dc resistance is measured at otherthan 20°C, it shall be corrected by using the multiplying factorsgiven in Table 2.In cases where the lay is definitely known, the incrementmay be calculated if desired (Explanatory Note 3).
For conductors to be used in covered or insulated wiresor cables,direct current (DC) resistance measurement may beused instead of the method outlined in Section 9, to determinecompliance with this specification.The cross-sectional area of the compact round conductorshall be not less than 98 %of the cross-sectional area asspecified in Column 1 of Table 1.The manufacturer shall determine the cross-sectionalarea by Test Method B 263. In applying this method，theincrement in mass per unit length resulting from stranding maybe the applicable value specified in 9.1 or may be calculatedfrom the measured dimensions of the sample under test.In caseof question regarding area compliance, the actual mass per unitlength increment due to stranding shall be calculated.ASTM B496 pdf download.