ASTM B787/B787M-04

    Standard Specification for 19 Wire Combination Unilay-Stranded Copper Conductors for Subsequent Insulation

    SUPERSEDED (see Active link, below)


      Format Pages Price  
    PDF Version 5 $50.40   ADD TO CART


    1. 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.


    2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.

    ASTM Standards

    B1 Specification for Hard-Drawn Copper Wire

    B2 Specification for Medium-Hard-Drawn Copper Wire

    B3 Specification for Soft or Annealed Copper Wire

    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

    B246 Specification for Tinned Hard-Drawn and Medium-Hard-Drawn 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


    ICS Code

    ICS Number Code 29.060.20 (Cables)

    UNSPSC Code

    UNSPSC Code 26121517(Copper wire)


    DOI: 10.1520/B0787_B0787M-04

    ASTM International is a member of CrossRef.


    Citing ASTM Standards
    Back to Top