ASTM B3-13(2024)

Standard Specification for Soft or Annealed Copper Wire

ABSTRACT
This specification covers drawn and annealed or soft round bare copper wire for electrical purposes. The matterial shall be copper of such quality and purity that the finished product shall have the properties and characteristics prescribed. Tensile strength, elongation, and resistivity of the wires shall be determined. A micrometer caliper equipped with a vernier shall be used to measure the material dimensions. The wires shall be subjected to surface finish and shall conform to the particularized requirements.
SCOPE
1.1 This specification covers drawn and annealed or soft round bare copper wire for electrical purposes (see Explanatory Note 1).  
1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.  
1.2.1 Exception—For density, resistivity and temperature, the values stated in SI units are to be regarded as standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 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: 31-Mar-2024
• ICS: 77.150.30 - Copper products
• Technical Committee: B01 - Electrical Conductors
• Drafting Committee: B01.04 - Conductors of Copper and Copper Alloys

Relations

• Replaces: ASTM B3-13(2018) - Standard Specification for Soft or Annealed Copper Wire
• Effective Date: 01-Apr-2024
• Referred By: ASTM B8-23 - Standard Specification for Concentric-Lay-Stranded Copper Conductors, Hard, Medium-Hard, or Soft
• Effective Date: 01-Apr-2024
• Referred By: ASTM B972-10(2020)e1 - Standard Specification for Nickel-Coated Braid and Ribbon Flat Copper Wire Intended for use in Electronic Application
• Effective Date: 01-Apr-2024
• Referred By: ASTM B174-17 - Standard Specification for Bunch-Stranded Copper Conductors for Electrical Conductors
• Effective Date: 01-Apr-2024
• Referred By: ASTM B787/B787M-04(2020) - Standard Specification for 19 Wire Combination Unilay-Stranded Copper Conductors for Subsequent Insulation
• Effective Date: 01-Apr-2024
• Referred By: ASTM B971-10(2020)e1 - Standard Specification for Silver-Coated Braid and Ribbon Flat Copper Wire intended for use in Electronic Application
• Effective Date: 01-Apr-2024
• Referred By: ASTM B77-07(2018) - Standard Test Method for Thermoelectric Power of Electrical-Resistance Alloys
• Effective Date: 01-Apr-2024
• Referred By: ASTM B496-16(2021) - Standard Specification for Compact Round Concentric-Lay-Stranded Copper Conductors
• Effective Date: 01-Apr-2024
• Referred By: ASTM B173-17 - Standard Specification for Rope-Lay-Stranded Copper Conductors Having Concentric-Stranded Members, for Electrical Conductors
• Effective Date: 01-Apr-2024
• Referred By: ASTM B784-01(2017)e1 - Standard Specification for Modified Concentric-Lay-Stranded Copper Conductors for Use in Insulated Electrical Cables
• Effective Date: 01-Apr-2024
• Referred By: ASTM B902/B902M-13(2018) - Standard Specification for Compressed Round Stranded Copper Conductors, Hard, Medium-Hard, or Soft Using Single Input Wire Construction
• Effective Date: 01-Apr-2024
• Referred By: ASTM B172-17 - Standard Specification for Rope-Lay-Stranded Copper Conductors Having Bunch-Stranded Members, for Electrical Conductors
• Effective Date: 01-Apr-2024
• Referred By: ASTM F68-16 - Standard Specification for Oxygen-Free Copper in Wrought Forms for Electron Devices
• Effective Date: 01-Apr-2024
• Referred By: ASTM B258-18 - Standard Specification for Standard Nominal Diameters and Cross-Sectional Areas of AWG Sizes of Solid Round Wires Used as Electrical Conductors
• Effective Date: 01-Apr-2024
• Referred By: ASTM D1676-17 - Standard Test Methods for Film-Insulated Magnet Wire
• Effective Date: 01-Apr-2024

Overview

ASTM B3-13(2024): Standard Specification for Soft or Annealed Copper Wire provides requirements for drawn and annealed (soft) round bare copper wire, specifically intended for electrical applications. This internationally recognized standard, developed by ASTM International, ensures that copper wire used as an electrical conductor meets precise characteristics for quality, dimensions, surface condition, and electrical properties. The document is widely referenced in the electrical industry to support reliable, efficient, and safe performance in a variety of applications.

Key Topics

• Material Quality: The specification mandates that the copper wire be manufactured from high-purity copper, consistent with the requirements set by ASTM standards, ensuring optimal conductivity and performance.
• Physical Properties:
  • Elongation: Specifies minimum elongation values based on wire diameter, indicating ductility and flexibility necessary for electrical installations.
  • Dimensional Tolerances: Outlines precise allowable variations in wire diameter, which are critical for uniform electrical performance and compatibility with connectors and equipment.
  • Surface Finish: Requires the wire be free of imperfections not consistent with best commercial practice, supporting long-term reliability.
• Electrical Properties:
  • Resistivity: Specifies maximum allowable electrical resistivity at 20°C, ensuring efficient current flow and minimal energy loss.
• Testing and Inspection:
  • Sampling Procedures: Describes methods for random sampling, tensile and elongation testing, resistivity measurement (per ASTM B193), and dimensional checks with micrometer calipers.
  • Lot Acceptance Criteria: Details procedures for lot inspection, defect limits, and acceptance protocols to verify compliance before shipment or use.

Applications

Soft or annealed copper wire manufactured under ASTM B3-13(2024) is essential for a broad range of electrical purposes, valued for its high conductivity, ductility, and ease of handling. Practical applications include:

• Electrical Wiring and Cables: Used as the base conductor in power distribution cables, building wiring, and internal electronic wiring owing to its excellent electrical properties.
• Fabrication of Braids and Twisted Cords: Preferred for stranded wire, braiding, and rope-lay wires, where flexibility and durability are required.
• Equipment Manufacturing: Utilized by manufacturers of transformers, motors, and generators where reliable electrical connections are critical.
• Specialty Applications: Suitable for telecommunications, grounding systems, and any scenario where soft copper conduction is needed.

Its precise properties and rigorous testing make soft or annealed copper wire compliant with ASTM B3 a trusted choice wherever consistent, high-quality electrical conductors are needed.

Related Standards

For comprehensive compliance and best practices, users of ASTM B3-13(2024) should consider the following related specifications:

• ASTM B49: Specification for Copper Rod for Electrical Purposes, which defines copper feedstock quality suitable for wire drawing.
• ASTM B193: Test Method for Resistivity of Electrical Conductor Materials, referenced for measuring wire resistivity.
• ASTM B258: Specification for Standard Nominal Diameters and Cross-Sectional Areas of AWG Sizes of Solid Round Wires, related to dimensional requirements.
• National Institute of Standards and Technology (NIST) Handbook 100: Offers in-depth wire tables and guidance on wire diameters, gauges, and physical properties.

Summary

ASTM B3-13(2024) specifies the essential characteristics, test methods, and acceptance criteria for soft or annealed copper wire for electrical purposes. Adhering to this standard helps ensure electrical safety, reliability, and performance across a myriad of critical applications, contributing to global best practices in the electrical conductor industry.

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: B3 − 13 (Reapproved 2024)
Standard Specification for
Soft or Annealed Copper Wire
This standard is issued under the fixed designation B3; 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.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope Wires Used as Electrical Conductors
2.3 Other Standards:
1.1 This specification covers drawn and annealed or soft
NBS Handbook 100 —Copper Wire Tables
round bare copper wire for electrical purposes (see Explanatory
Note 1).
3. Ordering Information
1.2 The values stated in inch-pound units are to be regarded
3.1 Orders for material under this specification shall include
as standard. The values given in parentheses are mathematical
the following information:
conversions to SI units that are provided for information only
3.1.1 Quantity of each size,
and are not considered standard.
3.1.2 Wire size: diameter in inches (see 5.3 and Table 1),
1.2.1 Exception—For density, resistivity and temperature,
3.1.3 Type of copper, if special (Section 4),
the values stated in SI units are to be regarded as standard.
3.1.4 Package size (see 10.1),
1.3 This standard does not purport to address all of the
3.1.5 Special package marking, if required, and
safety concerns, if any, associated with its use. It is the
3.1.6 Place of inspection (see 7.1).
responsibility of the user of this standard to establish appro-
4. Materials
priate safety, health, and environmental practices and deter-
mine the applicability of regulatory limitations prior to use.
4.1 The material shall be copper of such quality and purity
1.4 This international standard was developed in accor-
that the finished product shall have the properties and charac-
dance with internationally recognized principles on standard-
teristics prescribed in this specification.
ization established in the Decision on Principles for the
NOTE 1—Specification B49 defines copper suitable for use.
Development of International Standards, Guides and Recom-
mendations issued by the World Trade Organization Technical 4.2 Copper bars of special qualities, forms, or types, as may
Barriers to Trade (TBT) Committee. be agreed upon between the manufacturer and the purchaser,
and which will conform to the requirements prescribed in this
2. Referenced Documents
specification may also be used.
2.1 The following documents of the issue in effect at the
5. General Requirements (see Section 8)
time of reference form a part of this specification to the extent
referenced herein: 5.1 Tensile Strength and Elongation—The wire shall con-
2 form to the requirements for elongation prescribed in Table 1
2.2 ASTM Standards:
(see Explanatory Note 2). No requirements for tensile strength
B49 Specification for Copper Rod for Electrical Purposes
are specified. For wire whose nominal diameter is more than
B193 Test Method for Resistivity of Electrical Conductor
0.001 in. (0.025 mm) greater than a size listed in Table 1, but
Materials
less than that of the next larger size, the requirements of the
B258 Specification for Standard Nominal Diameters and
next larger size shall apply.
Cross-Sectional Areas of AWG Sizes of Solid Round
5.2 Resistivity—The electrical resistivity at 20 °C shall not
2 2
exceed 875.20 Ω·lb/mile (0.15328 Ω·g/m ) (see Explanatory
This specification is under the jurisdiction of ASTM Committee B01 on
Note 5).
Electrical Conductorsand is the direct responsibility of Subcommittee B01.04 on
Conductors of Copper and Copper Alloys.
5.3 Dimensions and Permissible Variations—The wire sizes
Current edition approved April 1, 2024. Published May 2024. Originally
shall be expressed as the diameter of the wire in decimal
approved in 1912. Last previous edition approved in 2018 as B3 – 13 (2018). DOI:
fractions of an inch to the nearest 0.0001 in. (or 0.001 mm) (see
10.1520/B0003-13R24.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on Available from National Institute of Standards and Technology (NIST), 100
the ASTM website. 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
B3 − 13 (2024)
TABLE 1 Tensile Requirements
Diameter Area at 20 °C Elongation in
10 in.
(254 mm),
2 2
in. mm cmils in. mm
% min
0.4600 11.684 211 600 0.1662 107.0 35
0.4096 10.404 167 800 0.1318 85.0 35
0.3648 9.266 133 100 0.1045 67.4 35
0.3249 8.252 105 600 0.08291 53.5 35
0.2893 7.348 83 690 0.06573 42.4 30
0.2576 6.543 66 360 0.05212 33.6 30
0.2294 5.827 52 620 0.04133 26.7 30
0.2043 5.189 41 740 0.03278 21.2 30
0.1819 4.620 33 090 0.02599 16.8 30
0.1620 4.115 26 240 0.02061 13.3 30
0.1443 3.665 20 820 0.01635 10.5 30
0.1285 3.264 16 510 0.01297 8.37 30
0.1144 2.906 13 090 0.01028 6.63 30
0.1019 2.588 10 380 0.008155 5.26 25
0.0907 2.304 8 230 0.00646 4.17 25
0.0808 2.052 6 530 0.00513 3.31 25
0.0720 1.829 5 180 0.00407 2.63 25
0.0641 1.628 4 110 0.00323 2.08 25
0.0571 1.450 3 260 0.00256 1.65 25
0.0508 1.290 2 580 0.00203 1.31 25
0.0453 1.151 2 050 0.00161 1.04 25
0.0403 1.024 1 620 0.00128 0.823 25
0.0359 0.912 1 290 0.00101 0.654 25
0.0320 0.813 1 020 0.000804 0.517 25
0.0285 0.724 812 0.000638 0.411 25
0.0253 0.643 640 0.000503 0.324 25
0.0226 0.574 511 0.000401 0.259 25
0.0201 0.511 404 0.000317 0.205 20
0.0179 0.455 320 0.000252 0.162 20
0.0159 0.404 253 0.000199 0.128 20
0.0142 0.361 202 0.000158 0.102 20
0.0126 0.320 159 0.000125 0.081 20
0.0113 0.287 128 0.000100 0.065 20
0.0100 0.254 100 0.0000785 0.051 15
0.0089 0.226 79.2 0.0000622 0.040 15
0.0080 0.203 64.0 0.0000503 0.032 15
0.0071 0.180 50.4 0.0000396 0.026 15
0.0063 0.160 39.7 0.0000312 0.020 15
0.0056 0.142 31.4 0.0000246 0.016 15
0.0050 0.127 25.0 0.0000196 0.013 15
0.0045 0.114 20.2 0.000 0159 0.010 15
0.0040 0.102 16.0 0.0000126 0.0081 15
0.0035 0.089 12.2 0.00000962 0.0062 15
0.0031 0.079 9.61 0.00000755 0.0049 15
Explanatory Note 3). For diameters under 0.0100 in. (0.254 tension (see Explanatory Note 4). The elongation shall be
mm), the wire shall not vary from the specified diameter by measured between gauge marks placed originally 10 in. (242
more than plus and minus 0.0001 in. (0.0025 mm), and for
mm) apart upon the test specimen and expressed in percent of
diameters of 0.0100 in. (0.254 mm) and over the wire shall not the original length.
vary from the specified diameter by more than plus and minus
6.1.2 The elongation of wire with a nominal diameter equal
1 %, expressed to the nearest 0.0001 in. (or 0.001 mm).
to or less than 0.0808 in. (2.053 mm) may be determined as
described above or by measurements made between the jaws of
5.4 Joints—Necessary joints in the completed wire and in
the testing machine. When measurements are made between
the wire and rods prior to final drawing shall be made in
the jaws, the zero length shall be the distance between the jaws
accordance with the best commercial practice.
at the start of the tension test and be as near 10 in. (254 mm)
5.5 Finish—The wire shall be free of all imperfections not
as practicable. The final length shall be the distance between
consistent with the best commercial practice.
the jaws at the time of rupture. The fracture shall be between
gauge marks or jaws of the testing machine, depending on
6. Test Methods
method used, and not closer than 1 in. (25.4 mm) to either
6.1 Tensile Strength and Elongation—No test for tensile
gauge mark or jaw.
strength shall be required.
6.1.1 The elongation of wire with a nominal diameter 6.2 Resistivity—Determine the electrical resistivity of the
greater than 0.0808 in. (2.052 mm) shall be determined as the material in accordance with Test Method B193 (Explanatory
permanent increase in length due to the breaking of the wire in Note 5). The purchaser may accept certification that the wire
B3 − 13 (2024)
was drawn from stock meeting the International Standard for 7.2.4 specimen—a length of wire removed for test purposes
Annealed Copper instead of resistivity tests on the finished from any individual production unit of the sample.
wire.
7.3 sample size (Explanatory Note 6)—The number of
6.3 Dimensional Measurements—Dimensional measure- production units in a sample shall be as follows:
ments shall be made with a micrometer caliper equipped with
7.3.1 For elongation and resistivity determinations, the
a vernier graduated in 0.0001 in. (0.0025 mm). Measurements
sample shall consist of four production units. From each unit,
shall be made on at least three places on each unit selected for
one test specimen of sufficient length shall be removed for the
this test. If accessible, one measurement shall be taken on each
performance of the required tests.
end and one near the middle. The average of the three
7.3.2 For dimensional measurements, the sample shall con-
measurements shall determine compliance with the require-
sist of a quantity of production units shown in Table 2 under
ments.
the heading “First Sample.”
7.3.3 For surface-finish inspection and for packaging in-
6.4 Surface Finish—Make a surface-finish inspection with
spection (when specified by the purchaser at the time of placing
the unaided eye (normal spectacles acceptable).
the order) the sample shall consist of a quantity of production
7. Inspection
units shown in Table 3.
7.1 General (Explanatory Note 6 and Note 7)—Unless
8. Conformance Criteria (see Explanatory Note 6)
otherwise specified in the contract or purchase order, the
manufacturer shall be responsible for the performance of all 8.1 Any lot of wire, the samples of which comply with the
conformance criteria of this section, shall be considered as
inspection and test requirements specified.
7.1.1 All inspections and tests shall be made at the place of complying with the requirements of Section 5. Individual
production units that fail to meet one or more of the require-
manufacture unless otherwise especially agreed upon betwe
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