ASTM B786/B786M-08(2023) PDF
Standard Specification for 19 Wire Combination Unilay-Stranded Aluminum Conductors for Subsequent Insulation
Standard Specification for 19 Wire Combination Unilay-Stranded Aluminum Conductors for Subsequent Insulation
- Статус документа:
- Действующий
- Формат:
- Электронный (PDF)
- Количество страниц:
- 6
- Дата публикации:
- 1 октября 2023 г.
- Издание:
- B786/B786M
- ICS:
- 29.060.20
ABSTRACT This specification covers the standard requirements for bare combination unilay-stranded conductors made from round wires of aluminum 1350 and 8000 series of aluminum alloys, for insulated conductors to be used for electrical purposes. Aluminum 1350 wires in tempers -H19, -H16 or -H26, -H14 or -H24, and -H142 or -H242 and 8000 series aluminum alloy wires in tempers “0” and H1X or H2X are permitted. 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 conductors. Electric-butt welds, cold pressure welds, or electric-butt cold-upset welds may be made in the finished individual wires composing the conductor. Mechanical (tension) and electrical tests shall be performed on the wires composing the conductors that are annealed and not annealed after stranding. The mass and electrical resistance of a unit length of stranded conductor shall be determined as a function of the length of lay. The conductors shall meet the breaking strength, tensile strength, and bending strength requirements. SCOPE 1.1 This specification covers bare combination unilay-stranded conductors made from round wires of aluminum 1350 and 8000 series of aluminum alloys, for insulated conductors for electrical purposes. Aluminum 1350 wires in tempers -H19 (extra hard), -H16 or -H26 (3/4 hard), -H14 or -H24 (1/2 hard), and -H142 or -H242 (1/2 hard) and 8000 series aluminum alloys wires in tempers “0” and H1X or H2X are permitted. 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 conductors. 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 Fig. 1). FIG. 1 Cross Section of Conductor 1.1.1 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 (Note 2 and Note 3). Note 2: Prior to 1975, aluminum 1350 was designated as EC aluminum. Note 3: The aluminum and temper designations conform to ANSI Standard H35.1. Aluminum 1350 corresponds to Unified Numbering System A91350 in accordance with Practice E527. Unified Numbering System alloy designations for 8000 Series aluminum alloys in accordance with Practice E527 are listed in Table number 1 of Specification B800. 1.2 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard. 1.3 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Abstract
Overview
ASTM B786/B786M-08(2023): Standard Specification for 19 Wire Combination Unilay-Stranded Aluminum Conductors for Subsequent Insulation defines the requirements for bare, combination unilay-stranded aluminum conductors made from round wires of Aluminum 1350 and 8000 series alloys. These conductors are specifically designed for use as the core of insulated electrical conductors and are not intended for bare use. The standard establishes the construction, material, mechanical, and testing requirements, ensuring consistent performance and quality for electrical applications.
Combination unilay-stranded conductors constructed under this standard provide a uniform cross-section and mechanical strength, optimizing them for applications where subsequent insulation or covering is applied. The specification supports international commerce and conformity through alignment with globally recognized principles under the WTO Technical Barriers to Trade (TBT) Committee.
Key Topics
-
Material Requirements:
- Permitted alloys: Aluminum 1350 (tempers -H19, -H16, -H26, -H14, -H24, -H142, -H242) and 8000 series aluminum alloys (tempers "0," H1X, H2X).
- Temper designation and compliance with ANSI H35.1/H35.1(M) and applicable ASTM references.
-
Conductor Construction:
- 19-wire design: a central core with two helically wound layers, giving an outer diameter matching compressed-stranded equivalents.
- Alternate layering of wire diameters for optimized mechanical and electrical properties.
- Permitted types of wire joints: electric-butt welds, cold pressure welds, and electric-butt cold-upset welds.
-
Mechanical and Electrical Testing:
- Testing of wires both before and after stranding for tensile strength, breaking strength, and bending properties.
- Direct current (DC) resistance and mass as determined by lay length and strand configuration.
- Conformance testing for both pre-annealed and post-annealed wire products.
-
Lay and Direction:
- Lay lengths from 8 to 16 times the outer diameter; special lays available by agreement.
- Standard direction is left-hand lay unless otherwise specified.
-
Packaging and Marking:
- Clear instructions for packaging size, protection during handling and shipping, and detailed package labeling for traceability.
Applications
- Power and Electrical Cables: The primary use of ASTM B786/B786M conductors is as the core of insulated power cables for the distribution and transmission of electrical energy.
- Industrial Cabling: Suited for manufacturing of covered, insulated, or jacketed cables used in industrial facilities.
- Utility and Grid Infrastructure: Preferred in utility-grade applications where reliable performance and insulation compatibility are essential.
- Customized Wiring Solutions: Supports cable manufacturers needing consistent conductor configurations for specific insulation or covering processes.
By adhering to ASTM B786/B786M, manufacturers and purchasers ensure that stranded aluminum conductors meet strict requirements for electrical conductivity, mechanical strength, and dimensional consistency. This improves product reliability, safety, and interoperability within the electrical supply chain.
Related Standards
- ASTM B230/B230M: Specification for Aluminum 1350-H19 Wire for Electrical Purposes
- ASTM B609/B609M: Specification for Aluminum 1350 Round Wire, Annealed and Intermediate Tempers, for Electrical Purposes
- ASTM B800: Specification for 8000 Series Aluminum Alloy Wire for Electrical Purposes
- ASTM B801: Specification for Concentric-Lay-Stranded Conductors of 8000 Series Aluminum Alloy for Subsequent Covering or Insulation
- ANSI H35.1/H35.1(M): Alloy and Temper Designation Systems for Aluminum
- ASTM B193: Test Method for Resistivity of Electrical Conductor Materials
- ASTM B263: Test Method for Determination of Cross-Sectional Area of Stranded Conductors
- E527: Practice for Numbering Metals and Alloys in the Unified Numbering System (UNS)
These related standards support the technical foundation of ASTM B786/B786M and ensure harmonization of conductor production, testing, and designation across the electrical industry.
Keywords: ASTM B786, unilay-stranded conductor, aluminum conductor, electrical conductor, 19 wire conductor, aluminum alloy, conductor for insulation, stranded aluminum conductor, ASTM standard conductors.
Технические детали
- Технический комитет
- B01 - Electrical Conductors
- SKU
- ASTM B786/B786M-08(2023)
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