Cored, Annular, Concentric-Lay-Stranded Copper Conductors

B226: Standard Specification for Cored, Annular, Concentric-Lay-Stranded Copper Conductors

When designing and specifying electrical infrastructure, ensuring the integrity and performance of conductors is paramount. ASTM B226 provides an authoritative framework for cored, annular, concentric-lay-stranded copper conductors, offering engineers a proven standard for critical applications. Understanding this essential specification is key to selecting the right materials and ensuring the reliability of power and communication systems.

What is B226?

ASTM B226 is a comprehensive industry standard that establishes the specifications for manufacturing cored, annular, concentric-lay-stranded copper conductors. Originating from ASTM's commitment to material standards, this specification ensures that these specific conductor constructions, made from round soft copper wires (either uncoated or tin-coated), meet stringent performance criteria for electrical applications.

Scope & Purpose

This standard governs the design, construction, and material requirements for cored, annular, concentric-lay-stranded copper conductors. It details the permissible construction parameters, including the number of wires, lay lengths, and conductor diameters, for conductors intended for use bare or with various types of insulation or weatherproofing. Notably, it does not cover specialized constructions or those intended for extremely demanding applications like electric furnace leads where unique designs are necessary.

Who Must Comply?

• • Primary audience: Electrical Engineers, Materials Engineers, Product Engineers, Standards Engineers, and Wire and Cable Designers.
• • Industries affected: Electrical Equipment Manufacturing, Power Generation and Distribution, Telecommunications, and Industrial Automation.
• • Compliance nature: Voluntary for general use, but often specified as mandatory by purchasers in contracts and project specifications.
• • Enforcement: Compliance is typically verified through quality control testing by manufacturers and inspection by purchasers or third-party agencies during procurement.

Key Requirements Overview

• • The standard requires conductors to be constructed from round soft copper wires, which can be either uncoated or tin-coated, ensuring consistent electrical properties.
• • Professionals must ensure that the core material, whether fibrous or metallic, is suitable for its intended purpose and provides adequate support for the stranded wires.
• • Key provisions include detailed specifications for the lay length and direction of wires in successive layers to achieve specific conductor characteristics.
• • The standard outlines acceptable tolerances for conductor dimensions and specifies testing procedures for electrical and physical properties of the constituent wires, both before and after stranding.
• • It also defines requirements for joints, permitting welds or brazes in individual wires but limiting their number within a given length.

Related Standards & References

ASTM B226 often works in conjunction with other essential standards. For instance, ASTM B3 (Specification for Soft or Annealed Copper Wire) and ASTM B33 (Specification for Tin-Coated Soft or Annealed Copper Wire) define the properties of the raw copper wire used in B226 conductors. Additionally, ASTM B8 (Specification for Concentric-Lay-Stranded Copper Conductors, Hard, Medium-Hard, or Soft) provides a foundational understanding of concentric-lay stranding principles that are adapted and specified in B226 for cored, annular constructions.