Active Standard ASTM B784 | Developed by Subcommittee: B01.04
Book of Standards Volume: 02.03
Historical (view previous versions of standard)
This specification covers bare modified concentric-lay-stranded conductors made from round copper wires, either uncoated or coated with tin, lead, or lead alloy for general use in insulated electrical cables. These conductors shall be constructed with a central core consisting of not more than seven wires, surrounded by one or more layers of helically laid wires. For the purposes of this specification, conductors are classified as Class B modified, class C modified, and Class D modified. The conductors shall meet the prescribed construction requirements such as number of wires and diameter. Welds and brazes may be made in rods or in wires prior to final drawing. Welds and brazes may be made in the finished individual wires composing the conductor, but shall not be closer together than prescribed distance. Tests for the electrical properties of wires composing conductors made from soft or annealed copper wire, bare or coated, shall be made before stranding. Tests for the physical properties of these materials may be made upon the wires before stranding or upon wires removed from the complete stranded conductor.
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1.1 This specification covers bare modified concentric-lay-stranded conductors made from round copper wires, either uncoated or coated with tin, lead, or lead alloy for general use in insulated electrical cables. These conductors shall be constructed with a central core consisting of not more than seven wires, surrounded by one or more layers of helically laid wires.
1.2 For the purposes of this specification, conductors are classified as follows (Explanatory Note 1 and Note 2):
1.2.1 Class B Modified—Conductors to be insulated with various materials such as rubber, paper, and crosslink polyethylene.
1.2.2 Class C Modified and Class D Modified—Conductors where greater flexibility is required than is provided by Class B Modified conductors.
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 the values from the two systems may result in non- conformance with the specification. For conductor sizes designated by AWG or kcmil sizes, the requirements in SI units are numerically converted from the corresponding requirements in inch-pound units. 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, resitivity and temperature, the values stated in SI units are to be regarded as standard.
Note 1—The significant differences in this specification from Specification B8 are as follows: (1) The central core is permitted to contain up to seven wires drawn into the assembly with an infinite length of lay while Specification B8 permits only one, and (2) The construction is applicable only to stranded assemblies of 19 or more wires.
2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.
B3 Specification for Soft or Annealed Copper Wire
B8 Specification for Concentric-Lay-Stranded Copper Conductors, Hard, Medium-Hard, or Soft
B33 Specification for Tin-Coated Soft or Annealed Copper Wire for Electrical Purposes
B189 Specification for Lead-Coated and Lead-Alloy-Coated Soft Copper Wire for Electrical Purposes
B263 Test Method for Determination of Cross-Sectional Area of Stranded Conductors
B354 Terminology Relating to Uninsulated Metallic Electrical Conductors
Other StandardNBS Handbook 100 Available from National Technical Information Service (NTIS), 5285 Port Royal Rd., Springfield, VA 22161, http://www.ntis.gov.
ICS Number Code 29.060.20 (Cables)
UNSPSC Code 26121517(Copper wire)