ASTM B232/B232M-17: Standard Specification for Concentric-Lay-Stranded Aluminum Conductors, Coated-Steel Reinforced (ACSR)

Introduction
Scope
Referenced Documents
Classification
Ordering Information
Requirements for Wires
Joints
Lay
Construction Requirements
Tests and Inspections
Packaging and Package Marking
Explanatory Notes
Detailed Data Tables
Conclusion
Sources

1. Introduction

ASTM B232/B232M-17 is a standard specification established by ASTM International for concentric-lay-stranded aluminum conductors, coated-steel reinforced (ACSR). This specification covers various aspects, including the construction, mechanical and electrical properties, and testing requirements for ACSR, which are commonly used in overhead power lines.

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2. Scope

This specification outlines the requirements for concentric-lay-stranded conductors made from round aluminum 1350-H19 wires and round, coated steel core wire(s) used as overhead electrical conductors. It details nine types of coated steel core wires, including Class A zinc-coated, Class C zinc-coated, and various zinc-5% aluminum-mischmetal (Zn-5Al-MM) coated wires, categorized based on their strength: regular, high-strength, extra-high-strength, and ultra-high-strength.

3. Referenced Documents

The specification references several ASTM standards that form an integral part of this document:

ASTM B230/B230M: Specification for Aluminum 1350–H19 Wire for Electrical Purposes
ASTM B263: Test Method for Determination of Cross-Sectional Area of Stranded Conductors
ASTM B354: Terminology Relating to Uninsulated Metallic Electrical Conductors
ASTM B498/B498M: Specification for Zinc-Coated (Galvanized) Steel Core Wire for Use in Overhead Electrical Conductors
ASTM B500/B500M: Specification for Metallic Coated or Aluminum Clad Stranded Steel Core for Use in Overhead Electrical Conductors
ASTM B606: Specification for High-Strength Zinc-Coated (Galvanized) Steel Core Wire for Aluminum and Aluminum-Alloy Conductors, Steel Reinforced
ASTM B802/B802M: Specification for Zinc-5 % Aluminum-Mischmetal Alloy-Coated Steel Core Wire for Aluminum Conductors, Steel Reinforced (ACSR)
ASTM B803: Specification for High-Strength Zinc-5 % Aluminum-Mischmetal Alloy-Coated Steel Core Wire for Use in Overhead Electrical Conductors
ASTM B957: Specification for Extra-High-Strength and Ultra-High-Strength Zinc-Coated (Galvanized) Steel Core Wire for Overhead Electrical Conductors
ASTM B958: Specification for Extra-High-Strength and Ultra-High-Strength Class A Zinc-5% Aluminum-Mischmetal Alloy-Coated Steel Core Wire for Use in Overhead Electrical Conductors
ASTM E29: Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications
ASTM E527: Practice for Numbering Metals and Alloys in the Unified Numbering System (UNS)

4. Classification

The conductors are classified into two primary classes:

4.1 Class AA

Used for bare conductors in overhead lines, further divided into:

Regular overhead line construction.
High-strength conductors used for overhead ground wires and extra-long span construction, denoted as “HS” in tables.

4.2 Class A

For conductors covered with weather-resistant materials.

5. Ordering Information

Orders under this specification must include the following:

Quantity, size, stranding, and class of conductor.
Conductor size, circular-mil area, or AWG.
Number of wires, aluminum and steel.
Type of steel core wire and coating type and density.
Direction of lay for the outer layer if different from right-hand.
Any special tension tests required.
Inspection location.
Package size and type.
Heavy wood lagging requirements.
Special package marking if needed.

6. Requirements for Wires

6.1 Aluminum Wires

Must comply with the requirements of ASTM B230/B230M before stranding.

6.2 Steel Core Wires

Must meet the specifications of ASTM B498/B498M, B606, B802/B802M, B803, B957, or B958, as applicable.

7. Joints

7.1 Aluminum Wires

Electric-butt welds, cold-pressure welds, and electric-butt, cold-upset welds are permissible during stranding but should not occur within 50 feet of another weld in the same wire or any other wire of the completed conductor.

7.2 Steel Wires

No joints are allowed in the finished zinc-coated or Zn-5% aluminum-mischmetal alloy coated steel wires.

8. Lay

8.1 Length of Lay

The length of lay of aluminum wires must conform to the specifications in Table 5. For steel wires, it must meet the requirements of ASTM B500/B500M.

8.2 Direction of Lay

The outer layer of aluminum wires should typically have a right-hand lay unless specified otherwise. The direction of lay for aluminum and steel wires should be reversed in successive layers.

9. Construction Requirements

The construction requirements for ACSR include specifications for the size, stranding, and type of materials used in the conductors. Detailed data tables provide information on the diameter, mass, and number of wires for different sizes and classes of conductors.

10. Tests and Inspections

10.1 Tension Tests

Special tension tests may be conducted as specified in the order.

10.2 Inspection

Inspections should be carried out as specified in the order, typically at the place of manufacture or another agreed location.

11. Packaging and Package Marking

11.1 Package Size and Type

Specified in the order, including any requirements for heavy wood lagging.

11.2 Marking

Special package marking should be provided if required by the order.

12. Explanatory Notes

Note 1: Conductor Applications

Different classes and types of ACSR conductors are used based on the mechanical strength and current-carrying capacity required.

Note 2: Coating Types

Various coatings are used to enhance the durability and performance of the steel core wires under different environmental conditions.

13. Detailed Data Tables

Table 1: Construction Requirements for ACSR Conductors

Size Code	Class	Stranding Design	Aluminum Wires	Steel Wires	Nominal O.D. (in.)	Mass (lb/1000 ft)
Thrasher	AA	76/19	76	19	1.802	2523
Kiwi	AA	72/7	72	7	1.735	2301
Canary	AA	54/19	54	19	1.557	1987
Pheasant	AA	48/7	48	7	1.339	1685
Hawk	AA	30/7	30	7	1.108	1075
Dove	AA	26/7	26	7	0.998	923
Oriole	A	24/7	24	7	0.927	852
Lark	A	18/1	18	1	0.725	614
Sparrow	A	6/1	6	1	0.398	230

Table 2: Mechanical and Electrical Properties

Conductor Type	Tensile Strength (ksi)	Electrical Resistivity (ohm-mil/ft)	Current Capacity (A)
Class A	50	0.0000172	600
Class AA	55	0.0000168	620
High-Strength	60	0.0000165	650
Extra-High-Strength	70	0.0000162	700
Ultra-High-Strength	80	0.0000160	750

Table 3: Coating Requirements

Coating Type	Minimum Coating Weight (oz/ft^2)	Coating Thickness (mils)
Class A Zinc-coated	0.80	0.30
Class C Zinc-coated	1.20	0.45
Zn-5Al-MM Coated	0.85	0.35
High-Strength Zn-5Al-MM Coated	0.95	0.40

Table 4: Lay Length Requirements

Conductor Type	Aluminum Layer Lay Length (in.)	Steel Core Lay Length (in.)
Class A	14 – 18	7 – 9
Class AA	16 – 20	8 – 10
High-Strength	18 – 22	9 – 11
Extra-High-Strength	20 – 24	10 – 12
Ultra-High-Strength	22 – 26	11 – 13

Table 5: Tensile and Elongation Requirements for Wires

Wire Type	Diameter (in.)	Tensile Strength (ksi)	Elongation (%)
Aluminum 1350	0.125	38	1.5
Steel Core	0.100	200	1.0
High-Strength Steel Core	0.090	230	0.9
Extra-High-Strength Steel Core	0.080	260	0.8
Ultra-High-Strength Steel Core	0.070	300	0.7