19 Wire Combination Unilay-Stranded Aluminum Conductors for Subsequent Insulation

B786/B786M- 08: Standard Specification for 19 Wire Combination Unilay-Stranded Aluminum Conductors for Subsequent Insulation

For electrical engineers, cable designers, and procurement specialists involved in the construction of essential power and telecommunications infrastructure, understanding the precise material specifications is paramount. ASTM B786/B786M- 08 provides an authoritative framework for specifying 19-wire combination unilay-stranded aluminum conductors, ensuring reliable performance when these conductors are subsequently insulated. This standard is an essential guide for professionals who need to select and procure aluminum conductors that meet rigorous industry demands for electrical applications.

What is B786/B786M- 08?

ASTM B786/B786M- 08 is a comprehensive standard that defines the requirements for bare, 19-wire combination unilay-stranded aluminum conductors. Originating from ASTM Committee B01 on Electrical Conductors, its primary purpose is to establish uniform specifications for these conductors, facilitating their use in the manufacturing of insulated electrical cables for various applications.

Scope & Purpose

This standard governs the construction, materials, and testing of 19-wire combination unilay-stranded aluminum conductors. It specifically covers conductors made from aluminum alloys 1350 and 8000 series, detailing the wire diameters, stranding configuration, and acceptable tempers. The scope is focused on conductors intended for subsequent insulation and does not apply to conductors that are already insulated or intended for direct use without insulation.

Who Must Comply?

• • Primary Audience: Electrical Engineers, Cable Engineers, Materials Scientists, Manufacturing Engineers, Procurement Specialists, and Quality Control Inspectors.
• • Industries Affected: Electrical Power Transmission and Distribution, Telecommunications, Industrial Manufacturing, and Construction.
• • Compliance Nature: This standard is typically voluntary, adopted by manufacturers and purchasers through contractual agreements. However, it is widely recognized and often referenced in project specifications, making compliance a de facto requirement for market access and project acceptance.
• • Enforcement: Compliance is generally enforced through contractual obligations, purchaser inspections, and third-party certification bodies.

Key Requirements Overview

Professionals utilizing ASTM B786/B786M- 08 should be aware of several core provisions:

• • The standard requires conductors to be constructed with a specific 19-wire combination unilay-stranded configuration, featuring a central core wire surrounded by two layers of helically laid wires.
• • It specifies the acceptable aluminum alloys (1350 and 8000 series) and their corresponding tempers, ensuring material integrity and electrical performance.
• • Key provisions include detailed requirements for wire diameters, lay direction, and length, which are critical for achieving the desired conductor properties after insulation.
• • The standard outlines mechanical and electrical testing protocols for the completed conductor, or the individual wires, to verify conformance to specified tensile strength and resistivity requirements.

Related Standards & References

ASTM B786/B786M- 08 works in conjunction with several other ASTM standards to provide a complete specification. These include:

• • ASTM B230/B230M: Specification for Aluminum 1350-H19 Wire for Electrical Purposes, which defines