Concentric-Lay-Stranded Copper-Clad Steel Conductors

ASTM B228-11a: Standard Specification for Concentric-Lay-Stranded Copper-Clad Steel Conductors

When specifying electrical conductors for demanding applications where strength and conductivity are paramount, understanding the foundational standards is essential. ASTM B228-11a, the "Standard Specification for Concentric-Lay-Stranded Copper-Clad Steel Conductors," provides engineers and designers with a comprehensive framework for these specialized materials, ensuring reliability and performance in critical infrastructure.

What is ASTM B228-11a?

ASTM B228-11a is an industry-leading standard that defines the requirements for bare concentric-lay-stranded conductors manufactured from bare round copper-clad steel wires. Developed by ASTM International, this specification ensures that these conductors meet stringent material properties and construction criteria for general electrical use. Its primary purpose is to provide a reliable basis for the procurement and application of these robust conductors.

Scope & Purpose

This authoritative standard governs the material composition, construction, and performance characteristics of concentric-lay-stranded copper-clad steel conductors. It specifically details various grades of conductors based on strength and conductivity, such as High Strength (HS) and Extra High Strength (EHS) variants, as well as annealed (DSA) types. The scope includes requirements for the individual copper-clad steel wires prior to stranding and the final stranded conductor, but it does not cover insulated conductors or those intended for specialized applications beyond general electrical purposes.

Who Must Comply?

• • Primary audience: Electrical Engineers, Materials Engineers, Mechanical Engineers, Procurement Specialists, and Quality Control Inspectors involved in the design, manufacturing, or purchasing of electrical conductors.
• • Industries affected: Electrical Equipment Manufacturing, Wire and Cable Manufacturing, Utilities (power transmission and distribution), Telecommunications, Aerospace, and Automotive sectors.
• • Compliance nature: Primarily voluntary, but often becomes mandatory when referenced in contracts, purchase orders, or project specifications.
• • Enforcement: Compliance is typically verified through material testing, supplier audits, and inspection by the purchasing entity or a designated third-party inspector.

Key Requirements Overview

The standard requires that all individual copper-clad steel wires used in a conductor meet specific material property requirements from complementary ASTM standards, such as ASTM B227 or B910/B910M, depending on the grade. Professionals must ensure that the stranding process adheres to defined lay lengths and directions to achieve the specified conductor diameter and mechanical integrity. Key provisions include detailed tables outlining conductor construction, including the number and size of individual wires, and their corresponding minimum breaking strengths for various grades. The standard also addresses the acceptable methods for joining individual wires, ensuring these joints do not compromise the overall strength of the finished conductor.

Related Standards & References

ASTM B228-11a is often used in conjunction with other ASTM standards to ensure comprehensive material and performance compliance. These include:

• • ASTM B227: Specification for Hard-Drawn Copper-Clad Steel Wire, which details the requirements for the individual wires used in HS and EHS conductor grades.
• • ASTM B910/B910M: Specification for Annealed Copper-Clad Steel Wire, providing specifications for the wires used in DSA conductor grades.
• • ASTM B354: Terminology Relating