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
Technical Committee
B01 - Electrical Conductors

Relations

Effective Date
01-Apr-2024
Effective Date
01-Nov-2023
Effective Date
01-Jan-2020
Effective Date
01-Jan-2020
Effective Date
01-Jan-2020
Effective Date
01-Oct-2018
Effective Date
01-Apr-2017
Effective Date
01-Apr-2017
Effective Date
01-Apr-2017
Effective Date
01-Apr-2017
Effective Date
01-Apr-2017
Effective Date
01-Sep-2016
Effective Date
01-Apr-2015
Effective Date
01-Apr-2015
Effective Date
01-Apr-2015

Overview

ASTM B226-11(2021) - Standard Specification for Cored, Annular, Concentric-Lay-Stranded Copper Conductors is a comprehensive international standard developed by ASTM for the specification and use of round, soft copper wire conductors. These conductors may be uncoated or tin-coated and are designed for use in various electrical applications. The standard outlines requirements for the construction, physical and electrical properties, testing, packaging, and purchase of cored, annular, concentric-lay-stranded copper conductors.

Key Topics

  • Scope and Application: Covers stranded copper conductors with a central core, suitable for bare or covered (weather-resistant) use, and for insulation with materials like rubber, varnished cloth, or impregnated paper. Not recommended for “oil-filled” or “gas-filled” applications or where extreme flexibility is required (such as for electric furnace leads).
  • Material Requirements: Specifies the use of round, soft copper wires, either uncoated or tin-coated, conforming to related ASTM specifications.
  • Core Construction: The core can be any agreed-upon material, with sufficient size and surface firmness to serve as a stable base for overlaid wires. Fiber and metal supporting cores are allowable, as agreed between manufacturer and purchaser.
  • Conductor Configuration: Details on the nominal conductor size, wire arrangement, layers, diameters, and lay-up. Stresses proper placement and alignment for reliable conductor performance.
  • Testing and Quality: Lays out procedures for verifying the physical and electrical properties of component wires before and after stranding. Specifies acceptable tolerances and requirements for elongation and consistency.
  • Packaging and Marking: Requires robust packaging to prevent damage during transport, with clear, comprehensive identification of package contents and relevant details such as mass, length, size, conductor type, and corresponding order information.

Applications

Cored, annular, concentric-lay-stranded copper conductors produced in compliance with ASTM B226-11(2021) are widely used in electrical infrastructure due to their strength, stability, and reliable transmission capabilities. Common applications include:

  • Overhead and underground power transmission: Both bare and insulated forms are ideal for long runs where mechanical integrity and longevity are essential.
  • Heavy-duty electrical installations: Suitable for use as conductors within substations, large-scale distribution networks, and switchgear assemblies.
  • Cable manufacturing: These conductors are frequently embedded within multi-core power and control cables that require a central supporting core for improved strength and electrical properties.
  • Industrial environments: Used where weather-resistant or insulated conductors are critical, provided flexibility requirements are not extreme.

This standard is referenced globally, ensuring consistent quality and interoperability of copper electrical conductors in diverse installation and operating environments.

Related Standards

AstM B226-11(2021) refers to, and aligns with, several other key standards impacting copper conductor design, manufacturing, and application. These include:

  • 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
  • ASTM B172, B173, B174: Various specifications for rope-lay and bunch-stranded copper conductors
  • ASTM B263: Test Method for Determination of Cross-Sectional Area of Stranded Conductors
  • ASTM B354: Terminology Relating to Uninsulated Metallic Electrical Conductors

Other relevant standards include those from NIST (NBS Handbook 100-Copper Wire Tables) and ANSI (IEEE Standard 100), ensuring harmonization of terminology and measurement methods across the industry.

Keywords: cored conductor, annular copper conductor, concentric-lay-stranded, soft copper conductor, tin-coated copper, electrical conductor standards, ASTM copper conductor, stranded copper conductor.

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Frequently Asked Questions

ASTM B226-11(2021) is a technical specification published by ASTM International. Its full title is "Standard Specification for Cored, Annular, Concentric-Lay-Stranded Copper Conductors". This standard covers: 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.

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.

ASTM B226-11(2021) is classified under the following ICS (International Classification for Standards) categories: 29.060.20 - Cables. The ICS classification helps identify the subject area and facilitates finding related standards.

ASTM B226-11(2021) has the following relationships with other standards: It is inter standard links to ASTM B3-13(2024), ASTM B8-23, ASTM B787/B787M-04(2020), ASTM B33-10(2020)e1, ASTM B835-14(2020), ASTM B3-13(2018), ASTM B784-01(2017)e1, ASTM B172-17, ASTM B174-17, ASTM B8-11(2017), ASTM B173-17, ASTM B354-16, ASTM B172-10(2015), ASTM B173-10(2015), ASTM B174-10(2015). Understanding these relationships helps ensure you are using the most current and applicable version of the standard.

ASTM B226-11(2021) is available in PDF format for immediate download after purchase. The document can be added to your cart and obtained through the secure checkout process. Digital delivery ensures instant access to the complete standard document.

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 service@astm.org. 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
...

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