ASTM B784-01(2017)e1

Standard Specification for Modified Concentric-Lay-Stranded Copper Conductors for Use in Insulated Electrical Cables

ABSTRACT
This specification covers bare modified concentric-lay-stranded conductors made from round copper wires, either uncoated or coated with tin, lead, or lead alloy for general use in insulated electrical cables. These conductors shall be constructed with a central core consisting of not more than seven wires, surrounded by one or more layers of helically laid wires. For the purposes of this specification, conductors are classified as Class B modified, class C modified, and Class D modified. The conductors shall meet the prescribed construction requirements such as number of wires and diameter. Welds and brazes may be made in rods or in wires prior to final drawing. Welds and brazes may be made in the finished individual wires composing the conductor, but shall not be closer together than prescribed distance. Tests for the electrical properties of wires composing conductors made from soft or annealed copper wire, bare or coated, shall be made before stranding. Tests for the physical properties of these materials may be made upon the wires before stranding or upon wires removed from the complete stranded conductor.
SCOPE
1.1 This specification covers bare modified concentric-lay-stranded conductors made from round copper wires, either uncoated or coated with tin, lead, or lead alloy for general use in insulated electrical cables. These conductors shall be constructed with a central core consisting of not more than seven wires, surrounded by one or more layers of helically laid wires.  
1.2 For the purposes of this specification, conductors are classified as follows (Explanatory Note 1 and Note 2):  
1.2.1 Class B Modified—Conductors to be insulated with various materials such as rubber, paper, and crosslink polyethylene.  
1.2.2 Class C Modified and Class D Modified—Conductors where greater flexibility is required than is provided by Class B Modified conductors.  
1.3 The values stated in inch-pound or SI units are to be regarded separately as standard. Each system shall be used independently of the other. Combining the values from the two systems may result in non- conformance with the specification. For conductor sizes designated by AWG or kcmil sizes, the requirements in SI units are numerically converted from the corresponding requirements in inch-pound units. For conductor sizes designated by AWG or kcmil, the requirements in SI units have been numerically converted from corresponding values stated or derived in inch-pound units. For conductor sizes designated by SI units only, the requirements are stated or derived in SI units.  
1.3.1 For density, resistivity and temperature, the values stated in SI units are to be regarded as standard.
Note 1: The significant differences in this specification from Specification B8 are as follows: (1) The central core is permitted to contain up to seven wires drawn into the assembly with an infinite length of lay while Specification B8 permits only one, and (2) The construction is applicable only to stranded assemblies of 19 or more wires.  
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-2017
• ICS: 29.060.20 - Cables
• Technical Committee: B01 - Electrical Conductors
• Drafting Committee: B01.04 - Conductors of Copper and Copper Alloys

Relations

• Replaces: ASTM B784-01(2012) - Standard Specification for Modified Concentric-Lay-Stranded Copper Conductors for Use in Insulated Electrical Cables
• Effective Date: 01-Apr-2017
• 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 B33-10(2020)e1 - Standard Specification for Tin-Coated Soft or Annealed Copper Wire for Electrical Purposes
• 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 B8-11(2017) - Standard Specification for Concentric-Lay-Stranded Copper Conductors, Hard, Medium-Hard, or Soft
• Effective Date: 01-Apr-2017
• Refers: ASTM B354-16 - Standard Terminology Relating to Uninsulated Metallic Electrical Conductors
• Effective Date: 01-Sep-2016
• Refers: ASTM B33-10(2014) - Standard Specification for Tin-Coated Soft or Annealed Copper Wire for Electrical Purposes
• Effective Date: 01-Sep-2014
• Refers: ASTM B3-13 - Standard Specification for Soft or Annealed Copper Wire
• Effective Date: 01-Oct-2013
• Refers: ASTM B354-12 - Standard Terminology Relating to Uninsulated Metallic Electrical Conductors
• Effective Date: 01-Dec-2012
• Refers: ASTM B3-12 - Standard Specification for Soft or Annealed Copper Wire
• Effective Date: 15-Nov-2012
• Refers: ASTM B8-11 - Standard Specification for Concentric-Lay-Stranded Copper Conductors, Hard, Medium-Hard, or Soft
• Effective Date: 01-Apr-2011
• Refers: ASTM B263-04(2010) - Standard Test Method for Determination of Cross-Sectional Area of Stranded Conductors
• Effective Date: 01-Oct-2010
• Refers: ASTM B189-05(2010) - Standard Specification for Lead-Coated and Lead-Alloy-Coated Soft Copper Wire for Electrical Purposes
• Effective Date: 01-Oct-2010
• Refers: ASTM B33-10 - Standard Specification for Tin-Coated Soft or Annealed Copper Wire for Electrical Purposes
• Effective Date: 01-Apr-2010

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.
´1
Designation: B784 −01 (Reapproved 2017)
Standard Specification for
Modified Concentric-Lay-Stranded Copper Conductors for
Use in Insulated Electrical Cables
This standard is issued under the fixed designation B784; 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.
ε NOTE—Typos in Section 1 were corrected editorially in April 2017.
1. Scope 1.4 This international standard was developed in accor-
dance with internationally recognized principles on standard-
1.1 This specification covers bare modified concentric-lay-
ization established in the Decision on Principles for the
stranded conductors made from round copper wires, either
Development of International Standards, Guides and Recom-
uncoated or coated with tin, lead, or lead alloy for general use
mendations issued by the World Trade Organization Technical
in insulated electrical cables. These conductors shall be con-
Barriers to Trade (TBT) Committee.
structed with a central core consisting of not more than seven
wires, surrounded by one or more layers of helically laid wires.
2. Referenced Documents
1.2 For the purposes of this specification, conductors are
2.1 The following documents of the issue in effect at the
classified as follows (Explanatory Note 1 and Note 2):
dateofmaterialpurchaseformapartofthisspecificationtothe
1.2.1 Class B Modified—Conductors to be insulated with
extent referenced herein.
various materials such as rubber, paper, and crosslink polyeth-
2.2 ASTM Standards:
ylene.
B3 Specification for Soft or Annealed Copper Wire
1.2.2 Class C Modified and Class D Modified—Conductors
B8 Specification for Concentric-Lay-Stranded Copper
where greater flexibility is required than is provided by Class
Conductors, Hard, Medium-Hard, or Soft
B Modified conductors.
B33 Specification for Tin-Coated Soft or Annealed Copper
1.3 The values stated in inch-pound or SI units are to be
Wire for Electrical Purposes
regarded separately as standard. Each system shall be used
B189 Specification for Lead-Coated and Lead-Alloy-Coated
independently of the other. Combining the values from the two
Soft Copper Wire for Electrical Purposes
systems may result in non- conformance with the specification.
B263 Test Method for Determination of Cross-Sectional
For conductor sizes designated by AWG or kcmil sizes, the
Area of Stranded Conductors
requirements in SI units are numerically converted from the
B354 Terminology Relating to Uninsulated Metallic Electri-
correspondingrequirementsininch-poundunits.Forconductor
cal Conductors
sizesdesignatedbyAWGorkcmil,therequirementsinSIunits
2.3 Other Standard:
have been numerically converted from corresponding values
NBS Handbook 100
stated or derived in inch-pound units. For conductor sizes
designated by SI units only, the requirements are stated or
3. Ordering Information
derived in SI units.
3.1 Orders for material under this specification shall include
1.3.1 For density, resistivity and temperature, the values
the following information:
stated in SI units are to be regarded as standard.
3.1.1 Quantity of each size and class,
NOTE 1—The significant differences in this specification from Specifi-
3.1.2 Conductor size: circular-mil area or American Wire
cation B8 are as follows: (1)The central core is permitted to contain up to
Gage (AWG) (Section 6),
seven wires drawn into the assembly with an infinite length of lay while
3.1.3 Class (see 1.2 and Table 1),
Specification B8 permits only one, and (2) The construction is applicable
3.1.4 Temper (see 10.2),
only to stranded assemblies of 19 or more wires.
1 2
This specification is under the jurisdiction of ASTM Committee B01 on For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Electrical Conductors and is the direct responsibility of Subcommittee B01.04 on contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Conductors of Copper and Copper Alloys. Standards volume information, refer to the standard’s Document Summary page on
Current edition approved April 1, 2017. Published April 2017. Originally the ASTM website.
approved in 1988. Last previous edition approved in 2012 as B784 – 01 (2012). Available fromAvailable from National Technical Information Service (NTIS),
DOI: 10.1520/B0784-01R17E01. 5301 Shawnee Rd., Alexandria, VA 22312, http://www.ntis.gov.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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B784 − 01 (2017)
TABLE 1 Construction Requirements of Modified Concentric-Lay-Stranded Copper Conductors
NOTE 1—See Explanatory Note 5.
Size Class B Modified Class C Modified Class D Modified
Circular Mils American Number of Diameter Number of Diameter Number of Diameter
Wire Gage Wires (mils) (mm) Wires (mils) (mm) Wires (mils) (mm)
A
5 000 000 217 151.8 3.86 271 135.8 3.45 271 135.8 3.45
4 000 000 217 144.0 3.66 271 128.9 3.27 271 128.9 3.27
4 000 000 217 135.8 3.45 271 121.5 3.09 271 121.5 3.09
3 500 000 169 143.9 3.66 217 127.0 3.23 271 113.6 2.89
A
3 000 000 169 133.2 3.38 217 117.6 2.99 271 105.2 2.67
A
2 500 000 127 140.3 3.56 169 121.6 3.09 217 107.3 2.73
A
2 000 000 127 125.5 3.19 169 108.8 2.76 217 96.0 2.44
1 900 000 127 122.3 3.11 169 106.0 2.69 217 93.6 2.38
1 800 000 127 119.1 3.03 169 103.2 2.62 217 91.1 2.31
A
1 750 000 127 117.4 2.98 169 101.8 2.59 217 89.8 2.28
1 700 000 127 115.7 2.94 169 100.3 2.55 217 88.5 2.25
1 600 000 127 112.2 2.85 169 97.3 2.47 217 85.9 2.18
A
1 500 000 91 128.4 3.26 127 108.7 2.76 169 94.2 2.39
1 400 000 91 124.0 3.15 127 105.0 2.67 169 91.0 2.31
1 300 000 91 119.5 3.04 127 101.2 2.57 169 87.7 2.23
1 250 000 91 117.2 2.98 127 99.2 2.52 169 86.0 2.18
1 200 000 91 114.8 2.92 127 97.2 2.47 169 84.3 2.14
1 100 000 91 109.9 2.79 127 93.1 2.36 169 80.7 2.05
A
1 000 000 61 128.0 3.25 91 104.8 2.66 127 88.7 2.25
900 000 61 121.5 3.09 91 99.4 2.52 127 84.2 2.14
A
800 000 61 114.5 2.91 91 93.8 2.38 127 79.4 2.02
A
750 000 61 110.9 2.82 91 90.8 2.31 127 76.8 1.95
A
700 000 61 107.1 2.72 91 87.7 2.23 127 74.2 1.88
650 000 61 103.2 2.62 91 84.5 2.15 127 71.5 1.82
A
600 000 61 99.2 2.52 91 81.2 2.06 127 66.7 1.69
550 000 61 95.0 2.41 91 77.7 1.97 127 65.8 1.67
A
500 000 37 116.2 2.95 61 90.5 2.30 91 74.1 1.88
450 000 37 110.3 2.80 61 85.9 2.18 91 70.3 1.79
A
400 000 37 104.0 2.64 61 81.0 2.06 91 66.3 1.68
A
350 000 37 97.3 2.47 61 75.7 1.92 91 62.0 1.57
A
300 000 37 90.0 2.29 61 70.1 1.78 91 57.4 1.46
A
250 000 37 82.2 2.09 61 64.0 1.63 91 52.4 1.33
A
211 000 0000 19 105.5 2.68 37 75.6 1.92 61 58.9 1.50
A
167 000 000 19 94.0 2.39 37 67.3 1.71 61 52.4 1.33
A
133 000 00 19 83.7 2.13 37 60.0 1.52 61 46.7 1.19
A
105 000 0 19 74.5 1.89 37 53.4 1.36 61 41.6 1.06
A
83 000 1 19 66.4 1.69 37 47.6 1.21 61 37.0 0.94
A
These sizes of conductors provide for one or more schedules of preferred series and commonly are used in the industry. The sizes not marked are given simplyasa
matter of reference and it is suggested that their use be discouraged.
3.1.5 Whether coated or uncoated; if coated, designate type 5. Lay
of coating (see 10.1 and 10.2),
5.1 The lay of a layer of wires shall be not less than eight
3.1.6 Details of special-purpose lays, if required (see 5.2),
nor more than sixteen times the outside diameter of that layer,
3.1.7 Lagging, if required (see 14.2),
except that for conductors composed of 37 wires or more, this
3.1.8 Special package marking, if required (Section 13),
requirement shall apply only to the two outer layers.The lay of
3.1.9 Place of inspection (Section 12), and
the layers other than the two outer layers shall be at the option
of the manufacturer, unless otherwise agreed upon.
4. Joints
5.2 Other lays for special purposes shall be furnished by
4.1 Welds and brazes may be made in rods or in wires prior
special agreement between the manufacturer and the purchaser
to final drawing.Welds and brazes may be made in the finished
(Explanatory Note 3).
individual wires composing the conductor, but shall not be
5.3 The direction of lay of the outer layer shall be left-hand
closer together than prescribed in Table 2.
unless the direction of lay is specified otherwise by the
purchaser.
5.4 The direction of lay shall be reversed in successive
TABLE 2 Minimum Distance Between Joints in the Completed
Conductor
layers, unless otherwise specified by the purchaser.
Number of Wires in Conductor Soft All Classes
19 1 ft 6. Construction
A
20 and over 1 ft in a layer
6.1 The areas of cross section, numbers, and diameters of
A
Except as indicated, the limitations apply to closeness of joints throughout the
wires in the various classes of concentric-lay-stranded conduc-
completed conductor.
tors shall conform to the requirements prescribed in Table 1.
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B784 − 01 (2017)
6.2 The diameters of the wires listed in Table 1 are nominal. 9. Mass and Resistance
Where “combination strand” is required in order to insulate the
9.1 The mass and electrical resistance of a unit length of
conductor properly (strands in the outer layer having a larger
stranded conductor are a function of the length of lay. The
diameter than those in the inner layers) the diameters shall be
approximate mass and electrical resistance may be determined
subject to a tolerance of 65 %, provided that the area of cross
using the standard increments shown in Table 3. When greater
section after stranding is in accordance with Section 11.
accuracy is desired, the increment based on the specific lay of
6.3 Where compressed stranding is required in order to the conductor may be calculated (Explanatory Note 8).
insulate the conductor properly, one or more layers of any
10. Requirements for Wires
stranded conductor consisting of 19 wires or more may be
slightly compressed, thereby reducing the outside diameter of 10.1 The purchaser shall designate the type of wire and the
the conductor by not more than 3 %, provided that the area of
kind of coating, if any, to be used in the conductor.
cross section after stranding is in accordance with Section 11.
10.2 Beforestranding,thecopperwireusedshallmeetallof
the requirements of ASTM Specifications B3, B33, and B189
7. Physical and Electrical Tests of Stranded Conductors
that are applicable to its type.
of Soft Wires
10.3 Thecentralcoreshallbemadeofwireofthesametype
7.1 Tests for the electrical properties of wires composing
and temper as the concentric layers, unless otherwise specified.
conductors made from soft or annealed copper wire, bare or
coated, shall be made before stranding.
11. Variation in Area
7.2 Tests for the physical properties of soft or annealed
11.1 The area of cross section of the completed conductor
copper wire, bare or coated, may be made upon the wires shall be not less than 98 % of the area indicated in Column 1
before stranding or upon wires removed from the complete
of Table 1. Unless otherwise specified by the purchaser, the
strandedconductor,butneednotbemadeuponboth.Careshall manufacturer may have the option of determining the cross-
be taken to avoid mechanical injury to wire removed from the
sectional area by either of the following methods; except that
conductor for the purpose of testing. in case of a question regarding area compliance, the method of
11.1.2 shall be used.
7.3 The physical properties of wires when tested before
11.1.1 The area of cross section of a conductor may be
stranding shall conform to the applicable requirements of 10.2.
determined by calculations from diameter measurements, ex-
7.4 The physical properties of wires removed from the
pressed to four decimal places, of its component wires at any
completed stranded conductor shall be permitted to vary from
point when measured perpendicularly to their axes.
the applicable requirements of 10.2 by the following amounts
11.1.2 The area of cross section of a conductor may be
(Explanatory Note 4):
determined byTest Method B263. In applying that method, the
7.4.1 Average of Results Obtained on All Wires Tested—The
increment in mass resulting from stranding may be the appli-
minimum elongation required shall be reduced in numerical
cable value specified in 9.1 or may be calculated from the
value 5 (for example, from 30 to 25 %) from the numerical
measured component dimensions of the sample under test. In
requirements for the wire before stranding.
case of a question regarding area compliance, the actual mass
7.4.2 Results Obtained on Individual Wires—Theelongation
increment due to stranding shall be calculated.
ofindividualwiresshallbereducedinnumericalvalue15from
the minimum requirements before stranding (that is, 10 in 12. Inspection
addition to the 5 allowed in 7.4.1), but in no case shall the
12.1 Unless otherwise specified in the contract or purchase
elongation of any individual wire be less than 5 %.
order, the manufacturer shall be responsible for the perfor-
mance of all inspection and test requirements specified.
7.5 In the event that the requirements prescribed in 7.4.2 are
met but those prescribed in 7.4.1 are not met, a retest shall be
12.2 All inspections and tests shall be made at the place of
permitted wherein all wires of the conductor shall be tested for
manufactureunlessotherwiseagreeduponbythemanufacturer
the purpose of final determination of conformance to 7.4.
and the purchaser at the time of purchase.
7.6 Elongation tests to determine compliance shall not be
12.3 The manufacturer shall afford the inspector represent-
made on the conductor as a unit (Explanatory Note 6).
ing the purchaser all reasonable manufacturer’s facilities to
satisfy that the material is being furnished in accordance with
7.7 If a tinning, lead-coating, or lead-alloy-coating test is
this specification.
required, it shall be made on the wires prior to stranding.
8. Density
TABLE 3 Standard Increments Due to Stranding
Increment of Resistance
8.1 For the purpose of calculating mass per unit length,
Type of Conductor
and Mass, %
cross sections, etc., the density of the copper shall be taken as
Classes B Modified, C Modified, and D 2
3 3
0.32117 lb/in. or 8.89 g/cm at 20°C (Note 2 and Explanatory
Modified, 2 000 000 cmil and under
Note 7). Over 2 000 000 to 3 000 000 cmil 3
Over 3 000 000 to 4 000 000 cmil 4
NOTE 2—The term “mass” is being used in this specification as being Over 4 000 000 to 5 000 000 cmil 5
more technically correct. It replaces the term “weight.”
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B784 − 01 (
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