ASTM B787/B787M-04
(Specification)Standard Specification for 19 Wire Combination Unilay-Stranded Copper Conductors for Subsequent Insulation
Standard Specification for 19 Wire Combination Unilay-Stranded Copper Conductors for Subsequent Insulation
ABSTRACT
This specification covers electrical contact alloys with the nominal composition of 75% silver, 24.5% copper, and 0.5% nickel in the form of rods, wires, strips, and sheets. Raw materials shall be of such quality and purity that the products, which shall be finished by such operations as cold working, heat treatment, annealing, turning, grinding, or pickling, shall adhere to the chemical composition and mechanical property requirements prescribed here. Besides analysis for the elements silver, copper, and nickel, further analysis is to be made for suspected or indicated impurities, such as zinc, iron, cadmium, and lead, to make sure that their total does not exceed specified limits. Mechanical tests, which are to be conducted at room temperature, shall evaluate the materials' tensile strength, elongation, Rockwell hardness, and area and thickness reduction.
SCOPE
1.1 This specification covers bare combination unilay-stranded conductors made from round copper wires, either uncoated or coated with tin or lead alloy for insulated conductors for electrical purposes. These conductors shall be constructed with a central core wire surrounded by two layers of helically laid wires, resulting in an outer diameter equal to the compressed-stranded equivalent conductor. (See Explanatory Note 1 and Note 2).
Note 1—For the purpose of this specification, combination unilay conductor is defined as follows: a central core wire surrounded by a layer of six helically laid wires of the same diameter as the core wire with a helically laid outer layer containing six smaller wires alternated between six wires of the same diameter as the wires in the layer underneath. Both layers have a common length and direction of lay (see ).
1.2 For the purpose of this specification, normal conductor classification (Class AA, A, B, C) is not applicable as these conductors are intended for subsequent insulation. The descriptive term combination unilay-stranded shall be used in place of conductor classification.
1.3 The values stated in inch-pound or SI units are to be regarded separately as standard. Each system shall be used independently of the other. Combining values from the two systems may result in nonconformance with the specification. For conductor sizes designated by AWG or kcmil, the requirements in SI units have been numerically converted from corresponding values, stated or derived, in inch-pound units. For conductor sizes designated by SI units only, the requirements are stated or derived in SI units.
1.3.1 For density, resistivity, and temperature, the values stated in SI units are to be regarded as standard.
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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Designation: B787/B787M – 04
Standard Specification for
19 Wire Combination Unilay-Stranded Copper Conductors
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for Subsequent Insulation
This standard is issued under the fixed designation B787/B787M; the number immediately following the designation indicates the year
of original adoption 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. Scope 2. Referenced Documents
2.1 The following documents of the issue in effect on date
1.1 This specification covers bare combination unilay-
stranded conductors made from round copper wires, either of material purchase form a part of this specification to the
uncoated or coated with tin or lead alloy for insulated conduc- extent referenced herein.
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tors for electrical purposes. These conductors shall be con- 2.2 ASTM Standards:
structed with a central core wire surrounded by two layers of B1 Specification for Hard-Drawn Copper Wire
helically laid wires, resulting in an outer diameter equal to the B2 Specification for Medium-Hard-Drawn Copper Wire
compressed-stranded equivalent conductor. (See Explanatory B3 Specification for Soft or Annealed Copper Wire
Note 1 and Note 2). B33 Specification forTinned Soft orAnnealed CopperWire
for Electrical Purposes
NOTE 1—For the purpose of this specification, combination unilay
B189 Specification for Lead-Coated and Lead-Alloy-
conductor is defined as follows: a central core wire surrounded by a layer
Coated Soft Copper Wire for Electrical Purposes
of six helically laid wires of the same diameter as the core wire with a
helically laid outer layer containing six smaller wires alternated between B246 Specification for Tinned Hard-Drawn and Medium-
six wires of the same diameter as the wires in the layer underneath. Both
Hard-Drawn Copper Wire for Electrical Purposes
layers have a common length and direction of lay (see Fig. 1).
B263 Test Method for Determination of Cross-Sectional
Area of Stranded Conductors
1.2 For the purpose of this specification, normal conductor
B354 Terminology Relating to Uninsulated Metallic Elec-
classification (Class AA, A, B, C) is not applicable as these
trical Conductors
conductorsareintendedforsubsequentinsulation.Thedescrip-
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2.3 Other Standard:
tive term combination unilay-stranded shall be used in place of
NBS Handbook 100—Copper Wire Tables of the National
conductor classification.
Bureau of Standards
1.3 The values stated in inch-pound or SI units are to be
regarded separately as standard. Each system shall be used
3. Ordering Information
independently of the other. Combining values from the two
3.1 Orders for materials under this specification shall in-
systems may result in nonconformance with the specification.
clude the following information:
For conductor sizes designated byAWG or kcmil, the require-
3.1.1 Quantity of each size,
ments in SI units have been numerically converted from
3.1.2 Conductor Size: Circular-mil area or American Wire
corresponding values, stated or derived, in inch-pound units.
Gage, AWG (Section 7 and Table 1),
For conductor sizes designated by SI units only, the require-
3.1.3 Stranding (see Explanatory Note 3),
ments are stated or derived in SI units.
3.1.4 Temper (see 4.2),
1.3.1 For density, resistivity, and temperature, the values
3.1.5 Whether coated or uncoated; if coated, designate type
stated in SI units are to be regarded as standard.
of coating (see 4.1 and 4.2),
1.4 This standard does not purport to address all of the
3.1.6 Details of special-purpose lays, if required (see 6.2),
safety concerns, if any, associated with its use. It is the
3.1.7 When physical tests shall be made (see 9.2 and 9.3),
responsibility of the user of this standard to establish appro-
3.1.8 Package size (see 15.1),
priate safety and health practices and determine the applica-
3.1.9 Lagging, if required (see 15.2),
bility of regulatory limitations prior to use.
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This specification is under the jurisdiction of ASTM Committee B01 on For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Electrical Conductors and is the direct responsibility of Subcommittee B01.04 on contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Conductors of Copper and Copper Alloys. Standards volume information, refer to the standard’s Document Summary page on
Current edition approved Sept. 1, 2004. Published September 2004. Originally the ASTM website.
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approved in 1988. Last previous edition approved in 2001 as B787/B787M – 01. Available from National Institute of Standards and Technology (NIST), 100
DOI: 10.1520/B0787_B0787M-04. Bureau Dr., Stop 3460, Gaithersburg, MD 20899-3460.
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