ASTM B226-11(2021)

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

ABSTRACT
This specification covers cored, annular, concentric-lay-stranded conductors made from round soft copper wires either uncoated or coated with tin for use as electrical conductors. The core may be of any materials and its size and surface firmness as a base for the overlaid wires shall be adequated to prevent forcing or dropping of any wire out of its layer position. No splice shall be made in the conductor as a whole, welds or brazes may be made in the finished individual wires. The materials shall conform to the required nominal conductor size, number of layers of wires, number, diameter, lay-up wires, approximate core diameter, and maximum conductor diameter. The mass per unit length and electrical resistance of a unit length of stranded conductor are a function of the length of lay and shall be calculated. The are of cross section of a conductor shall be considered to be the sum of the cross-sectional areas of its component wires at any section when measured perpendicularly to their individual axes.
SCOPE
1.1 This specification covers cored, annular, concentric-lay-stranded conductors made from round soft copper wires, either uncoated or coated with tin for use as electrical conductors (Explanatory Note 1 and Note 2).  
1.2 The constructions prescribed herein are suitable for bare conductors, or for conductors to be covered with weather-resistant (weather-proof) material, or for conductors to be insulated with rubber, varnished cloth, or impregnated paper, except types such as “oil-filled” or “gas-filled” (Explanatory Note 3).  
1.3 Cored, annular conductor constructions not included in this specification shall be specifically agreed upon between the manufacturer and the purchaser when placing the order.  
1.4 These constructions are not recommended for use as electric furnace leads where great flexibility is required and special conductor designs are indicated in consideration of the particular service requirements.  
1.5 The SI values for density are regarded as the standard. For all other properties the inch-pound values are to be regarded as standard and the SI units may be approximate.  
1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 30-Sep-2021
• ICS: 29.060.20 - Cables
• Technical Committee: B01 - Electrical Conductors
• Drafting Committee: B01.04 - Conductors of Copper and Copper Alloys

Relations

• Refers: ASTM B3-13(2024) - Standard Specification for Soft or Annealed Copper Wire
• Effective Date: 01-Apr-2024
• Refers: ASTM B8-23 - Standard Specification for Concentric-Lay-Stranded Copper Conductors, Hard, Medium-Hard, or Soft
• Effective Date: 01-Nov-2023
• Refers: ASTM B787/B787M-04(2020) - Standard Specification for 19 Wire Combination Unilay-Stranded Copper Conductors for Subsequent Insulation
• Effective Date: 01-Jan-2020
• Refers: ASTM B33-10(2020)e1 - Standard Specification for Tin-Coated Soft or Annealed Copper Wire for Electrical Purposes
• Effective Date: 01-Jan-2020
• Refers: ASTM B835-14(2020) - Standard Specification for Compact Round Stranded Copper Conductors Using Single Input Wire Construction
• Effective Date: 01-Jan-2020
• Refers: ASTM B3-13(2018) - Standard Specification for Soft or Annealed Copper Wire
• Effective Date: 01-Oct-2018
• Refers: ASTM B784-01(2017)e1 - Standard Specification for Modified Concentric-Lay-Stranded Copper Conductors for Use in Insulated Electrical Cables
• Effective Date: 01-Apr-2017
• Refers: ASTM B172-17 - Standard Specification for Rope-Lay-Stranded Copper Conductors Having Bunch-Stranded Members, for Electrical Conductors
• Effective Date: 01-Apr-2017
• Refers: ASTM B174-17 - Standard Specification for Bunch-Stranded Copper Conductors for Electrical Conductors
• Effective Date: 01-Apr-2017
• Refers: ASTM B8-11(2017) - Standard Specification for Concentric-Lay-Stranded Copper Conductors, Hard, Medium-Hard, or Soft
• Effective Date: 01-Apr-2017
• Refers: ASTM B173-17 - Standard Specification for Rope-Lay-Stranded Copper Conductors Having Concentric-Stranded Members, for Electrical Conductors
• Effective Date: 01-Apr-2017
• Refers: ASTM B354-16 - Standard Terminology Relating to Uninsulated Metallic Electrical Conductors
• Effective Date: 01-Sep-2016
• Refers: ASTM B172-10(2015) - Standard Specification for Rope-Lay-Stranded Copper Conductors Having Bunch-Stranded Members, for Electrical Conductors
• Effective Date: 01-Apr-2015
• Refers: ASTM B173-10(2015) - Standard Specification for Rope-Lay-Stranded Copper Conductors Having Concentric-Stranded Members, for Electrical Conductors
• Effective Date: 01-Apr-2015
• Refers: ASTM B174-10(2015) - Standard Specification for Bunch-Stranded Copper Conductors for Electrical Conductors
• Effective Date: 01-Apr-2015

Overview

ASTM B226-11(2021): Standard Specification for Cored, Annular, Concentric-Lay-Stranded Copper Conductors provides requirements for the manufacture and performance of specialized copper conductors used in electrical applications. This specification, developed by ASTM, covers conductors constructed from round, soft copper wires, which may be uncoated or tin-coated. It is intended for the production of cored, annular, concentric-lay-stranded copper electrical conductors for use in a range of electrical and utility installations. The standard outlines the relevant material, construction, testing, and quality requirements needed to ensure the safety, reliability, and consistency of these conductors.

Key Topics

• Covered Conductor Types: The standard specifies cored, annular, concentric-lay-stranded copper conductors. These consist of multiple layers of copper wires arranged in concentric layers around a core, which can be made from a variety of suitable materials and is chosen based on the application's needs.
• Material Options: Conductors can use either uncoated or tin-coated soft copper wires. The copper must conform to referenced specifications for electrical purity and mechanical properties.
• Core Materials and Construction: The core can be fibrous or metallic and must provide sufficient support to maintain wire positioning in the layered strands.
• Physical and Electrical Properties: The specification defines nominal conductor sizes, allowed variation in dimensions, density, area of cross-section, and maximum diameter for reliable performance.
• Testing Requirements: Wires are tested for mechanical and electrical properties, both before and after stranding, to confirm compliance. Methods include tests for elongation, coating, mass, and cross-sectional area.
• Packaging and Marking: Requirements for packaging, protection against shipping damage, and traceable markings on delivery reels are outlined to facilitate safe handling and proper identification during storage and installation.

Applications

• Power Distribution: These copper conductors are widely used in utility and industrial electrical systems, where high reliability and low electrical resistance are needed.
• Overhead and Underground Cables: Suitable for both bare and covered conductors, including those insulated with weather-resistant materials, rubber, varnished cloth, or impregnated paper.
• Custom Installations: The standard allows for custom construction upon agreement between manufacturer and purchaser, enabling use in projects with unique engineering requirements.
• Not for Extreme Flexibility: ASTM B226-11(2021) does not recommend these constructions for electric furnace leads or applications where exceptional flexibility is needed.

Related Standards

To support complete and consistent electrical system design, ASTM B226-11(2021) references a number of other industry standards, including:

• ASTM B3 - Specification for Soft or Annealed Copper Wire
• ASTM B8 - Specification for Concentric-Lay-Stranded Copper Conductors
• ASTM B33 - Specification for Tin-Coated Soft or Annealed Copper Wire for Electrical Purposes
• ASTM B172, B173, B174, B496, B784, B787/B787M, B835, B902 - Additional standards detailing rope-lay, bunch-stranded, and compact conductor constructions
• ASTM B263 - Test Method for Determination of Cross-Sectional Area of Stranded Conductors
• ASTM B354 - Terminology Relating to Uninsulated Metallic Electrical Conductors
• ANSI/IEEE 100 - The Authoritative Dictionary of IEEE Standards Terms
• NIST Handbook 100 - Copper Wire Tables

Practical Value

ASTM B226-11(2021) enhances the quality and interoperability of electrical installations by:

• Ensuring consistent conductor manufacturing and performance
• Providing clear criteria for material selection and construction
• Facilitating accurate calculation of electrical and physical properties, vital for engineering and safety
• Enabling procurement confidence with detailed requirements for marking, packaging, and documentation

For engineers, utilities, and manufacturers, compliance with ASTM B226-11(2021) means reliable, efficient, and safe copper conductors designed for demanding electrical applications.

Keywords: cored conductor, annular stranded, concentric-lay, copper electrical conductor, ASTM B226, tin-coated copper, power cable standards, electrical conductor specification, stranded copper conductor, conductor testing.

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: B226 −11 (Reapproved 2021)
Standard Specification for
Cored, Annular, Concentric-Lay-Stranded Copper
Conductors
This standard is issued under the fixed designation B226; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 2.2 ASTM Standards:
B3 Specification for Soft or Annealed Copper Wire
1.1 This specification covers cored, annular, concentric-lay-
B8 Specification for Concentric-Lay-Stranded Copper
stranded conductors made from round soft copper wires, either
Conductors, Hard, Medium-Hard, or Soft
uncoated or coated with tin for use as electrical conductors
B33 Specification for Tin-Coated Soft or Annealed Copper
(Explanatory Note 1 and Note 2).
Wire for Electrical Purposes
B172 Specification for Rope-Lay-Stranded Copper Conduc-
1.2 The constructions prescribed herein are suitable for bare
torsHavingBunch-StrandedMembers,forElectricalCon-
conductors, or for conductors to be covered with weather-
ductors
resistant (weather-proof) material, or for conductors to be
B173 Specification for Rope-Lay-Stranded Copper Conduc-
insulated with rubber, varnished cloth, or impregnated paper,
tors Having Concentric-Stranded Members, for Electrical
except types such as “oil-filled” or “gas-filled” (Explanatory
Conductors
Note 3).
B174 Specification for Bunch-Stranded Copper Conductors
1.3 Cored, annular conductor constructions not included in
for Electrical Conductors
this specification shall be specifically agreed upon between the
B263 Test Method for Determination of Cross-Sectional
manufacturer and the purchaser when placing the order.
Area of Stranded Conductors
B354 Terminology Relating to Uninsulated Metallic Electri-
1.4 These constructions are not recommended for use as
cal Conductors
electric furnace leads where great flexibility is required and
B496 Specification for Compact Round Concentric-Lay-
special conductor designs are indicated in consideration of the
Stranded Copper Conductors
particular service requirements.
B784 Specification for Modified Concentric-Lay-Stranded
1.5 The SI values for density are regarded as the standard.
Copper Conductors for Use in Insulated Electrical Cables
For all other properties the inch-pound values are to be
B787/B787M Specification for 19 Wire Combination
regarded as standard and the SI units may be approximate.
Unilay-Stranded Copper Conductors for Subsequent Insu-
lation
1.6 This international standard was developed in accor-
B835 Specification for Compact Round Stranded Copper
dance with internationally recognized principles on standard-
Conductors Using Single Input Wire Construction
ization established in the Decision on Principles for the
B902 Specification for Compressed Round Stranded Copper
Development of International Standards, Guides and Recom-
Conductors, Hard, Medium-Hard, or Soft Using Single
mendations issued by the World Trade Organization Technical
Input Wire Construction
Barriers to Trade (TBT) Committee.
2.3 ANSI Standard:
IEEE Standard 100 The Authoritative Dictionary of IEEE
2. Referenced Documents
Standards Terms
2.1 The following documents in effect at the time of
2.4 NIST Standard:
reference form a part of these methods to the extent referenced
NBS Handbook 100—Copper Wire Tables
herein:
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
This specification is under the jurisdiction of ASTM Committee B01 on Standards volume information, refer to the standard’s Document Summary page on
Electrical Conductors and is the direct responsibility of Subcommittee B01.04 on the ASTM website.
Conductors of Copper and Copper Alloys. Available from American National Standards Institute (ANSI), 25 W. 43rd St.,
Current edition approved Oct. 1, 2021. Published October 2021. Originally 4th Floor, New York, NY 10036, http://www.ansi.org.
approved in 1948. Last previous edition approved in 2016 as B226 – 11 (2016). Available from National Institute of Standards and Technology (NIST), 100
DOI: 10.1520/B0226-11R21. Bureau Dr., Stop 1070, Gaithersburg, MD 20899-1070, http://www.nist.gov.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
B226 − 11 (2021)
3. Ordering Information 4.4 The proper treatment of the fibrous core, if any treat-
ment be required, shall be left to the discretion of the
3.1 Orders for material under this specification shall include
manufacturerunlessotherarrangementsaremadeatthetimeof
the following information:
purchase.
3.1.1 Quantity of each size,
4.5 If a metal supporting type of core is required, special
3.1.2 Conductor size: circular-mil area (Section 7 and Table
arrangements will be necessary between the manufacturer and
1),
the purchaser.
3.1.3 Whether coated or uncoated; if coated, a tin coating
only (Section 11),
5. Joints
3.1.4 Specific kind and treatment of core material (Section
4), 5.1 No splice shall be made in the conductor as a whole.
3.1.5 Details of special-purpose lays, if required (see 6.1 Welds or brazes may be made in the finished individual wires.
and 6.2 and Explanatory Note 3), Not more than one of the wires in any given layer shall be
3.1.6 Package size (Section 14), spliced in any 1-ft length of that layer.
3.1.7 Lagging, if required (see 14.2),
5.2 All joints shall be made in a workmanlike manner and
3.1.8 Special package marking, if required (Section 14.3),
shall be approximately the diameter of the unjointed wire.
and
3.1.9 Place of inspection (Section 13). 6. Lay
6.1 The length of lay of the respective layers of wires shall
4. Core
be at the option of the manufacturer unless otherwise agreed
upon with the purchaser (Explanatory Note 3).
4.1 Thecoremaybeofanymaterialormaterialssuitablefor
the purpose as agreed upon by the manufacturer and the
6.2 The direction of lay of the outer layer of wires shall be
purchaser when placing the order.
left hand, unless specified otherwise by the purchaser (Ex-
planatory Note 3).
4.2 Thesizeofthecoreanditssurfacefirmnessasabasefor
the overlaid wires shall be adequate to prevent the forcing or
6.3 The direction of lay shall be reversed in successive
dropping of any wire out of its layer position (Explanatory
layers (Explanatory Note 3).
Note 4).
7. Construction
4.3 If a specific kind of fibrous core is required by the
purchaser (such as manila rope, sisal, and so forth) it shall be 7.1 The nominal conductor size, number of layers of wires,
specified by him when placing the order (Explanatory Note 4). number, diameter, lay-up of wires, approximate core diameter,
TABLE 1 Construction of Cored, Annular, Concentric-Lay-Stranded Copper Conductors
Nominal Area of Number of Strands in Layers
Approximate Calculated Area of Maximum
Copper Diameter of
A
Diameter of Copper, Cross Outside Diameter,
Cross Wires, in.
Core, in. Section, cmils in.
1st 2nd 3rd Total
Section, cmils
5 000 000 2.875 0.1620 57 63 69 189 4 960 116 3.897
4 500 000 2.500 0.1620 50 56 62 168 4 408 992 3.517
4 000 000 2.250 0.1620 45 51 57 153 4 015 332 3.262
3 500 000 2.000 0.1620 40 45 52 137 3 595 428 3.007
3 000 000 1.625 0.1620 33 38 45 116 3 044 304 2.627
2 500 000 1.500 0.1440 34 40 46 120 2 488 320 2.394
2 000 000 1.313 0.1284 34 40 46 120 1 978 387 2.114
1 750 000 1.125 0.1280 30 35 42 107 1 753 088 1.923
1 500 000 1.000 0.1255 26 32 38 96 1 512 024 1.783
1 250 000 0.750 0.1255 21 26 33 80 1 260 020 1.533
1 000 000 0.563 0.1255 16 21 28 65 1 023 766 1.346
900 000 0.500 0.1172 16 22 28 66 906 565 1.234
800 000 0.468 0.1110 16 21 28 65 800 865 1.164
750 000 0.375 0.1172 12 18 24 54 741 735 1.108
A
The following plus tolerances are included in the calculation of maximum outside diameters:
Nominal Area, Plus Tolerance Included,
cmils mils
5 000 000 to 4 500 001 50
4 500 000 to 4 000 001 45
4 000 000 to 3 500 001 40
3 500 000 to 3 000 001 35
3 000 000 to 750 000 30
B226 − 11 (2021)
andmaximumconductordiametershallconformtotherequire- increment based on the specific lay of the conductor may be
ments prescribed in Table 1 (Explanatory Note 4). calculated (Explanatory Note 7).
10.2 The approximate mass per unit length of completed
8. Physical and Electrical Tests
conductors are given in Table 3 for information only, and
8.1 Tests for the electrical properties of wires composing
include mass per unit lengths of core calculated on the basis of
conductors made from soft or annealed copper wire, bare or
437 lb/in. ·1000 ft, using approximate core areas.
coated, shall be made before stranding.
11. Requirements for Wires
8.2 Tests for the physical properties of soft or annealed
copper wire, bare or coated, may be made upon the wires
11.1 The purchaser shall designate if the type of wire is tin
before stranding or upon wires removed from the completed
coated, or not (see 11.2).
strandedconductor,butneednotbemadeuponboth.Care
...