Concentric-Lay-Stranded Aluminum 1350 Conductors

B231/B231M-12: Standard Specification for Concentric-Lay-Stranded Aluminum 1350 Conductors

For electrical engineers and designers working with overhead power lines, telecommunications infrastructure, and general electrical construction, understanding the foundational specifications for conductor materials is essential. ASTM B231/B231M-12 provides this critical guidance, serving as an industry-leading standard for the design and manufacturing of concentric-lay-stranded aluminum conductors. Adherence to this specification ensures reliability, performance, and safety in a wide range of electrical applications.

What is B231/B231M-12?

ASTM B231/B231M-12 is the authoritative standard that defines the requirements for bare concentric-lay-stranded aluminum 1350 conductors. Developed by ASTM International, this specification details the construction methods, material properties, and classification of these conductors, which are fundamental components in electrical power transmission and distribution systems. Its primary purpose is to establish a common baseline for quality and performance, facilitating consistent and dependable conductor manufacturing and application.

Scope & Purpose

This comprehensive standard governs the construction of bare concentric-lay-stranded aluminum 1350 conductors, including those made from various tempers of aluminum 1350 wire. It specifies requirements for conductors intended for general electrical purposes, including use in overhead lines, applications requiring coverage with weather-resistant materials, and insulated conductor designs demanding greater flexibility. While it covers the conductor construction itself, it does not extend to the materials used for covering or insulation, nor does it detail the specific installation procedures or environmental performance criteria beyond the inherent properties of the conductor.

Who Must Comply?

• • Primary audience: Electrical Engineers, Design Engineers, Materials Engineers, Wire and Cable Manufacturers, and Quality Control Inspectors.
• • Industries affected: Electrical Power Transmission and Distribution, Telecommunications, General Electrical Construction, and Wire and Cable Manufacturing.
• • Compliance nature: Typically voluntary, but often mandated by project specifications, utility standards, and contractual agreements.
• • Enforcement: Compliance is generally ensured through quality control processes by manufacturers, inspection by third-party agencies, and verification during project acceptance by clients or regulatory bodies.

Key Requirements Overview

The standard requires that aluminum 1350 wire used in conductor construction meets specified temper and purity requirements, with extra hard (H19) being common for bare overhead conductors. Professionals must ensure that the stranding process adheres to defined lay lengths and directions to achieve the required mechanical and electrical properties, with specific lay requirements varying by conductor class. Key provisions include detailed tables outlining conductor sizes, wire counts, and diameters for different classes (AA, A, B, C, D), each suited for distinct applications from basic overhead lines to highly flexible insulated cables. The standard also outlines acceptable joint types and their placement within the conductor wires to maintain electrical integrity and mechanical strength.

Related Standards & References

ASTM B231/B231M-12 works in conjunction with several other ASTM standards to provide a complete specification for aluminum conductors. ASTM B230/B230M (Specification for Aluminum 1350-H19 Wire for Electrical Purposes) provides the foundational requirements for the individual aluminum wires used in stranding. **ASTM