ASTM B 784 Standard Specification for Modified Concentric-Lay-Stranded Copper Conductors for Use in Insulated Electrical Cables
ASTM B784 絕緣電纜用改進的同芯絞捻銅導線標準規范
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.
This abstract is a brief summary of the referenced standard. It is informational only and not an official part of the standard; the full text of the standard itself must be referred to for its use and application. ASTM does not give any warranty express or implied or make any representation that the contents of this abstract are accurate, complete or up to date.
1. Scope
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 B 8 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 B 8 permits only one, and (2) The construction is applicable only to stranded assemblies of 19 or more wires.
2. Referenced Documents (purchase separately)
ASTM Standards
B3 Specification for Soft or Annealed Copper Wire
B8 Specification for Concentric-Lay-Stranded Copper Conductors, Hard, Medium-Hard, or Soft
B33 Specification for Tinned 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
B8 Specification for Concentric-Lay-Stranded Copper Conductors, Hard, Medium-Hard, or Soft
B33 Specification for Tinned 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 Standard
NBS Handbook 100
Index Terms
copper conductors for insulated wires; copper modified concentric-lay-stranded; electrical copper conductors; 
