ASTM B787/B787M-04(2014)

Standard Specification for 19 Wire Combination Unilay-Stranded Copper Conductors for Subsequent Insulation

ABSTRACT
This specification covers electrical contact alloys with the nominal composition of 75% silver, 24.5% copper, and 0.5% nickel in the form of rods, wires, strips, and sheets. Raw materials shall be of such quality and purity that the products, which shall be finished by such operations as cold working, heat treatment, annealing, turning, grinding, or pickling, shall adhere to the chemical composition and mechanical property requirements prescribed here. Besides analysis for the elements silver, copper, and nickel, further analysis is to be made for suspected or indicated impurities, such as zinc, iron, cadmium, and lead, to make sure that their total does not exceed specified limits. Mechanical tests, which are to be conducted at room temperature, shall evaluate the materials' tensile strength, elongation, Rockwell hardness, and area and thickness reduction.
SCOPE
1.1 This specification covers bare combination unilay-stranded conductors made from round copper wires, either uncoated or coated with tin or lead alloy for insulated conductors for electrical purposes. These conductors shall be constructed with a central core wire surrounded by two layers of helically laid wires, resulting in an outer diameter equal to the compressed-stranded equivalent conductor. (See Explanatory Note 1 and Note 2).  
Note 1: For the purpose of this specification, combination unilay conductor is defined as follows: a central core wire surrounded by a layer of six helically laid wires of the same diameter as the core wire with a helically laid outer layer containing six smaller wires alternated between six wires of the same diameter as the wires in the layer underneath. Both layers have a common length and direction of lay (see Fig. 1).  
1.2 For the purpose of this specification, normal conductor classification (Class AA, A, B, C) is not applicable as these conductors are intended for subsequent insulation. The descriptive term combination unilay-stranded shall be used in place of conductor classification.  
1.3 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard.  
1.3.1 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.  
1.3.2 For conductor sizes designated by SI units only, the requirements are stated or derived in SI units.  
1.3.3 For density, resistivity, and temperature, the values stated in SI units are to be regarded as standard.  
1.4 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 and health practices and determine the applicability of regulatory limitations prior to use.

General Information

• Status: Historical
• Publication Date: 31-Aug-2014
• ICS: 29.060.20 - Cables
• Technical Committee: B01 - Electrical Conductors
• Drafting Committee: B01.04 - Conductors of Copper and Copper Alloys

Relations

• Replaces: ASTM B787/B787M-04(2009) - Standard Specification for 19 Wire Combination Unilay-Stranded Copper Conductors for Subsequent Insulation
• Effective Date: 01-Sep-2014
• Replaced By: ASTM B787/B787M-04(2020) - Standard Specification for 19 Wire Combination Unilay-Stranded Copper Conductors for Subsequent Insulation
• Effective Date: 01-Jan-2020
• Referred By: ASTM B226-11(2021) - Standard Specification for Cored, Annular, Concentric-Lay-Stranded Copper Conductors
• Effective Date: 01-Sep-2014
• Referred By: ASTM B8-11(2017) - Standard Specification for Concentric-Lay-Stranded Copper Conductors, Hard, Medium-Hard, or Soft
• Effective Date: 01-Sep-2014

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation:B787/B787M −04 (Reapproved 2014)
Standard Specification for
19 Wire Combination Unilay-Stranded Copper Conductors
for Subsequent Insulation
This standard is issued under the fixed designation B787/B787M; the number immediately following the designation indicates the year
of original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.
A superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica-
1.1 This specification covers bare combination unilay-
bility of regulatory limitations prior to use.
stranded conductors made from round copper wires, either
uncoated or coated with tin or lead alloy for insulated conduc-
2. Referenced Documents
tors for electrical purposes. These conductors shall be con-
2.1 The following documents of the issue in effect on date
structed with a central core wire surrounded by two layers of
of material purchase form a part of this specification to the
helically laid wires, resulting in an outer diameter equal to the
extent referenced herein.
compressed-stranded equivalent conductor. (See Explanatory
Note 1 and Note 2).
2.2 ASTM Standards:
B1Specification for Hard-Drawn Copper Wire
NOTE 1—For the purpose of this specification, combination unilay
B2Specification for Medium-Hard-Drawn Copper Wire
conductor is defined as follows: a central core wire surrounded by a layer
of six helically laid wires of the same diameter as the core wire with a B3Specification for Soft or Annealed Copper Wire
helically laid outer layer containing six smaller wires alternated between
B33Specification for Tin-Coated Soft or Annealed Copper
six wires of the same diameter as the wires in the layer underneath. Both
Wire for Electrical Purposes
layers have a common length and direction of lay (see Fig. 1).
B189Specification for Lead-Coated and Lead-Alloy-Coated
1.2 For the purpose of this specification, normal conductor
Soft Copper Wire for Electrical Purposes
classification (Class AA, A, B, C) is not applicable as these
B246Specification for Tinned Hard-Drawn and Medium-
conductorsareintendedforsubsequentinsulation.Thedescrip-
Hard-Drawn Copper Wire for Electrical Purposes
tivetermcombinationunilay-strandedshallbeusedinplaceof
B263Test Method for Determination of Cross-Sectional
conductor classification.
Area of Stranded Conductors
B354Terminology Relating to Uninsulated Metallic Electri-
1.3 The values stated in either SI units or inch-pound units
cal Conductors
are to be regarded separately as standard. The values stated in
each system may not be exact equivalents; therefore, each 2.3 Other Standard:
NBS Handbook 100Copper Wire Tables of the National
system shall be used independently of the other. Combining
values from the two systems may result in non-conformance Bureau of Standards
with the standard.
3. Ordering Information
1.3.1 For conductor sizes designated byAWG or kcmil, the
requirementsinSIunitshavebeennumericallyconvertedfrom 3.1 Orders for materials under this specification shall in-
corresponding values, stated or derived, in inch-pound units. clude the following information:
1.3.2 For conductor sizes designated by SI units only, the 3.1.1 Quantity of each size,
requirements are stated or derived in SI units. 3.1.2 Conductor Size: Circular-mil area or American Wire
1.3.3 For density, resistivity, and temperature, the values Gage, AWG (Section 7 and Table 1),
stated in SI units are to be regarded as standard. 3.1.3 Stranding (see Explanatory Note 3),
3.1.4 Temper (see 4.2),
1.4 This standard does not purport to address all of the
3.1.5 Whether coated or uncoated; if coated, designate type
safety concerns, if any, associated with its use. It is the
of coating (see 4.1 and 4.2),
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 Sept. 1, 2014. Published September 2014. Originally the ASTM website.
approved in 1988. Last previous edition approved in 2009 as B787/B787M–04 Available from National Institute of Standards and Technology (NIST), 100
(2009). DOI: 10.1520/B0787_B0787M-04R14. 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
B787/B787M−04 (2014)
4.2.3 Specification B2.
4.2.4 Specification B1.
4.2.5 Specification B189.
4.2.6 Specification B246.
4.3 In combination unilay stranded conductors, the central
core wire shall be made of the same type and temper as the
layers, unless otherwise specified.
FIG. 1Cross Section of Conductor
5. Joints
5.1 Welds and brazes may be made in rods or in wires prior
TABLE 1 Construction Requirements for 19-Wire Combination
Unilay Stranded Copper Conductors tofinaldrawing.Weldsandbrazesmaybemadeinthefinished
individual wires composing the conductor, but shall not be
Size, American (or
A B
Brown and
Wire D Wire D closer together than 50 ft (15.24 m) for hard and medium-hard
1 2
Cross-Sectional Area Sharpe) Diameter, Diameter,
conductors, and 1 ft in a layer for soft conductors.
cmil sq mm Wire Gage mils mm mils mm
500 000 253.4 175.6 4.5 128.5 3.3
450 000 228.0 166.6 4.2 121.9 3.1
6. Lay
400 000 202.7 157.1 4.0 115.0 2.9
350 000 177.3 146.9 3.7 107.5 2.7 6.1 For combination unilay conductors the lay of a layer of
300 000 152.0 136.0 3.5 99.6 2.5
wires shall be not less than 8 nor more than 16 times the
250 000 126.7 124.2 3.2 90.9 2.3
outside diameter of the outer layer.
211 600 107.2 0000 114.2 2.4 83.6 2.1
167 800 85.0 000 101.7 2.6 74.5 1.9
6.2 Other lays for special purposes shall be furnished by
133 100 67.4 00 90.6 2.3 66.3 1.7
specialagreementbetweenthemanufacturerandthepurchaser
105 600 53.5 0 80.7 2.0 59.1 1.5
83 690 42.4 1 71.8 1.8 52.6 1.3
(Explanatory Note 4).
66 360 33.6 2 64.0 1.6 46.8 1.2
52 620 26.7 3 57.0 1.4 41.7 1.1
6.3 The direction of lay shall be left-hand unless the
41 740 21.1 4 50.7 1.3 37.1 0.9
direction of lay is specified otherwise by the purchaser.
33 090 16.8 5 45.2 1.1 33.1 0.8
26 240 13.3 6 40.2 1.0 29.4 0.7
7. Construction (Explanatory Note 3)
20 820 10.5 7 35.8 0.9 26.2 0.7
16 510 8.4 8 31.9 0.8 23.4 0.6
7.1 The cross-sectional areas, numbers, and diameters of
13 090 6.6 9 28.4 0.7 20.8 0.5
wires in the various conductors shall conform to the require-
10 380 5.3 10 25.3 0.6 18.5 0.5
6530 3.3 12 20.1 0.5 14.7 0.4
ments prescribed in Table 1.
4110 2.1 14 15.9 0.4 11.7 0.3
2580 1.3 16 12.6 0.3 9.2 0.2
7.2 ThediametersofthewireslistedinTable2arenominal.
1620 0.8 18 10.0 0.3 7.3 0.2
In order to produce an essentially round 19-wire construction,
1020 0.5 20 7.9 0.2 5.8 0.1
the outer 12-wire layer in the combination unilay product is
640 0.3 22 6.3 0.2 4.6 0.1
404 0.2 24 5.0 0.1 3.7 0.1 comprised of 6 wires of the same diameter as the wires in the
A
Equation to calculate D : 7-wire core, and 6 wires approximately 25% smaller. The
2-wire sizes are alternated around the 7-wire core (Fig. 1).
Cross2Sectional Area
Œ
16.2149
8. Physical and Electrical Tests of Conductors Stranded
B
Equation to calculate D : D × 0.732.
2 1
of Soft Wires
8.1 Tests for the electrical properties of wires composing
conductors made from soft or annealed copper wire, bare or
3.1.6 Details of special-purpose lays, if required (see 6.2),
coated, shall be made before stranding.
3.1.7 When physical tests shall be made (see 9.2 and 9.3),
8.2 Tests for the physical properties of soft or annealed
3.1.8 Package size (see 15.1),
copper wire, bare or coated, may be made upon the wires
3.1.9 Lagging, if required (see 15.2),
before stranding or upon wires removed from the complete
3.1.10 Special package marking, if required (Section 15),
strandedconductor,butneednotbemadeuponboth.Careshall
and
be taken to avoid mechanical injury to wire removed from the
3.1.11 Place of inspection (Section 13).
conductor for the purpose of testing.
4. Requirements for Wires
8.3 The physical properties of wire when tested before
4.1 The purchaser shall designate the type of wire and the stranding shall conform to the applicable requirements of 4.2.
kind of coating, if any, to be used in the conductor.
8.4 The physical properties of wires removed from the
4.2 Before stranding, the copper wire used shall meet all of completed stranded conductor shall be permitted to vary from
the applicable requirements of 4.2 by the amounts as follows
therequirementsofthefollowingASTMspecificationsthatare
applicable to its type: (Explanatory Note 5):
4.2.1 Specification B3. 8.4.1 AverageofResultsObtainedonAllWiresTested—The
4.2.2 Specification B33. minimum elongation required shall be reduced in numerical
B787/B787M−04 (2014)
TABLE 2 Diameters, Areas, and Masses of 19-Wire Combination Unilay Stranded Copper Conductors
Nominal Area Mass
Size of Conductor
A 2 2
cmil or AWG sq mm Nominal Diameter, in. Conductor, mm in. mm lbs/1000 ft lbs/mile g/m
500 000 253.4 0.784 19.914 0.392700 253.35 1544 8151 2297
450 000 228.0 0.744 18.878 0.353400 228.02 1389 7336 2067
400 000 202.7 0.701 17.805 0.314000 202.68 1235 6521 1838
350 000 177.3 0.656 16.662 0.274900 177.35 1081 5706 1609
300 000 152.0 0.607 15.418 0.235600 152.01 926.3 4891 1378
250 000 126.7 0.554 14.072 0.196300 126.68 771.9 4076 1149
0000 107.2 0.510 12.954 0.166200 107.22 653.3 3450 972.1
000 85.0 0.454 11.532 0.131800 85.02 518.1 2736 770.9
00 67.4 0.404 10.262 0.104500 67.44 410.9 2169 611.4
0 53.5 0.360 9.144 0.082910 53.51 325.8 1720 684.8
1 42.4 0.321 8.153 0.065730 42.41 258.4 1364 384.5
2 33.6 0.286 7.264 0.052120 33.62 204.9 1082 304.9
3 26.7 0.254 6.452 0.041330 26.77 162.5 858.1 241.8
4 21.1 0.226 5.740 0.032780 21.15 128.9 680.5 191.8
5 16.8 0.202 5.131 0.025990 16.77 102.2 539.6 152.1
6 13.3 0.179 4.547 0.020610 13.30 81.05 428.0 120.6
7 15.6 0.160 4.064 0.016350 10.55 64.28 339.4 95.65
8 8.4 0.143 3.632 0.012970 8.37 50.97 269.1 75.84
9 6.6 0.127 3.226 0.010280 6.63 40.42 213.4 60.14
10 5.3 0.113 2.870 0.008155 5.26 32.06 169.3 47.71
12 3.3 0.090 2.286 0.005130 3.31 20.16 106.5 30.00
14 2.1 0.071 1.803 0.003230 2.08 12.68 66.95 18.87
16 1.3 0.056 1.422 0.002030 1.31 7.974 42.10 11.87
18 0.8 0.045 1.143 0.001280 0.82 5.015 26.48 7.462
20 0.5 0.035 0.809 0.000804 0.52 3.154 16.65 4.693
22 0.3 0.028 0.703 0.000503 0.32 1.992 10.52 2.964
24 0.2 0.022 0.558 0.000317 0.20 1.249 6.59 1.859
A
To calculate the diameter, multiply the large wire diameter in Table 1 by 3 and add two times the small wire diameter.
Example: AWG 4/0 diameter = [(3(114.2) + 2 (83.6)] = 509.8
value 5 (for example, from 30 to 25%) from the numerical breaking strength of conductors made from medium-hard-
requirements for the wire before stranding. drawn wires, uncoated or coated, shall be not greater than the
8.4.2 ResultsObtainedonIndividualWires—Theelongation sum of the specified maximum breaking strengths of the
ofindividualwiresshallbereducedinnumericalvalue15from component wires. The minimum breaking strengths of wires
the minimum requirements before stranding (that is, 10 in shall be calculated using specified nominal diameters and
addition to the 5 allowed in 8.4.1), but in no case shall the specified minimum tensile strengths. The maximum breaking
elongation of any individual wire be less than 5%. strengths of wires shall be calculated using nominal diameters
and specified maximum tensile strengths. The free length
8.5 Intheeventthattherequirementsprescribedin8.4.2are
between grips of the test specimen shall be not less than 24 in.
met but those prescribed in 8.4.1 are not met, a retest shall be
(610 mm), and care shall be taken to ensure that the wires in
permittedwhereinallwiresoftheconductorshallbetestedfor
the conductor are evenly gripped during the test (Explanatory
the purpose of final determination of conformance to 8.4.
Note 6).
8.6 Elongation tests to determine compliance shall not be
9.3 When requested by the purchaser at the time of placing
made on the conductor as a unit.
theorder,tensiontestsonhard-drawnandmedium-hard-drawn
8.7 If a tinning or lead-alloy-coating test is required, it shall
wires,uncoatedorcoated,beforestrandingorasaunitmaybe
be made on the wires prior to stranding.
waived and tests made on wires removed from the completed
conductor. The test limits, based on a 10-in. (254-mm) gage
9. Physical and Electrical Tests of Conductors Stranded
length, for such tests shall be specified by the purchaser in the
of Hard-Drawn or Medium-Hard Drawn Wires
placing of individual orders (Explanatory Note 5).
9.1 Tests for the physical and electrical properties of wires
9.4 Ifatinningtestisrequired,itshallbemadeonthewires
composing conductors made from hard-drawn or medium-
prior to stranding.
hard-drawnwires,uncoatedorcoated,shallbemadebeforebut
not after stranding.
10. Density
9.2 At the option of the purchaser, tension and elongation
10.1 For the purpose of calculating masses, cross sections,
tests on hard-drawn and medium-hard-drawn wires, uncoated
and so forth, the density of the copper shall be taken as 8.89
3 3
or coated, before stranding may be waived, and the completed
g/cm (0.32117 lb/in. ) at 20°C (Explanatory Note 7).
hard-drawnandmedium-hard-drawnconductorsmaybetested
11. Mass and Resistance
asaunit.Thebreakingstrengthofthebareconductorssotested
shall be at least 90% of the total of the specified minimum 11.1 The mass and electrical resistance of a unit length of
breaking strengths of the component wires. The maximum stranded conductor are a function of the length of lay. The
B787/B787M−04 (2014)
approximate mass and electrical resistance may be determined 13.3 The manufacturer shall afford the inspector represent-
using the standard increment of 2%.When greater accuracy is ing the purchaser all reasonable manufacturer’s facilities to
desired, the increment based on the specific lay of the conduc-
satisfy him that the material is being furnished in accordance
tor may be calculated (Explanatory Note 8).
with this specification.
12. Variance in Area
14. Product Marking
12.1 The cross-sectional area of the completed conductor
14.1 The net weight, length (or lengths and number of
shall be not less than 98% of the area indicated in Column 1
lengths, if more than one length is incl
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: B787/B787M − 04 (Reapproved 2009) B787/B787M − 04 (Reapproved 2014)
Standard Specification for
19 Wire Combination Unilay-Stranded Copper Conductors
for Subsequent Insulation
This standard is issued under the fixed designation B787/B787M; 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
1.1 This specification covers bare combination unilay-stranded conductors made from round copper wires, either uncoated or
coated with tin or lead alloy for insulated conductors for electrical purposes. These conductors shall be constructed with a central
core wire surrounded by two layers of helically laid wires, resulting in an outer diameter equal to the compressed-stranded
equivalent conductor. (See Explanatory Note 1 and Note 2).
NOTE 1—For the purpose of this specification, combination unilay conductor is defined as follows: a central core wire surrounded by a layer of six
helically laid wires of the same diameter as the core wire with a helically laid outer layer containing six smaller wires alternated between six wires of
the same diameter as the wires in the layer underneath. Both layers have a common length and direction of lay (see Fig. 1).
1.2 For the purpose of this specification, normal conductor classification (Class AA, A, B, C) is not applicable as these
conductors are intended for subsequent insulation. The descriptive term combination unilay-stranded shall be used in place of
conductor classification.
1.3 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each
system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the
two systems may result in non-conformance with the standard.
1.3.1 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.
1.3.2 For conductor sizes designated by SI units only, the requirements are stated or derived in SI units.
1.3.3 For density, resistivity, and temperature, the values stated in SI units are to be regarded as standard.
1.4 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 and health practices and determine the applicability of regulatory
limitations prior to use.
2. Referenced Documents
2.1 The following documents of the issue in effect on date of material purchase form a part of this specification to the extent
referenced herein.
2.2 ASTM Standards:
B1 Specification for Hard-Drawn Copper Wire
B2 Specification for Medium-Hard-Drawn Copper Wire
B3 Specification for Soft or Annealed Copper Wire
B33 Specification for Tin-Coated Soft or Annealed Copper Wire for Electrical Purposes
B189 Specification for Lead-Coated and Lead-Alloy-Coated Soft Copper Wire for Electrical Purposes
B246 Specification for Tinned Hard-Drawn and Medium-Hard-Drawn Copper Wire for Electrical Purposes
B263 Test Method for Determination of Cross-Sectional Area of Stranded Conductors
B354 Terminology Relating to Uninsulated Metallic Electrical Conductors
2.3 Other Standard:
NBS Handbook 100 NBS Handbook 100—Copper Copper Wire Tables of the National Bureau of Standards
This specification is under the jurisdiction of ASTM Committee B01 on Electrical Conductors and is the direct responsibility of Subcommittee B01.04 on Conductors
of Copper and Copper Alloys.
Current edition approved Oct. 1, 2009Sept. 1, 2014. Published January 2010September 2014. Originally approved in 1988. Last previous edition approved in 20042009
as B787/B787M – 04.B787/B787M – 04 (2009). DOI: 10.1520/B0787_B0787M-04R09. 10.1520/B0787_B0787M-04R14.
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’sstandard’s Document Summary page on the ASTM website.
Available from National Institute of Standards and Technology (NIST), 100 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
B787/B787M − 04 (2014)
FIG. 1 Cross Section of Conductor
3. Ordering Information
3.1 Orders for materials under this specification shall include the following information:
3.1.1 Quantity of each size,
3.1.2 Conductor Size: Circular-mil area or American Wire Gage, AWG (Section 7 and Table 1),
3.1.3 Stranding (see Explanatory Note 3),
3.1.4 Temper (see 4.2),
3.1.5 Whether coated or uncoated; if coated, designate type of coating (see 4.1 and 4.2),
3.1.6 Details of special-purpose lays, if required (see 6.2),
3.1.7 When physical tests shall be made (see 9.2 and 9.3),
3.1.8 Package size (see 15.1),
3.1.9 Lagging, if required (see 15.2),
3.1.10 Special package marking, if required (Section 15), and
3.1.11 Place of inspection (Section 13).
4. Requirements for Wires
4.1 The purchaser shall designate the type of wire and the kind of coating, if any, to be used in the conductor.
TABLE 1 Construction Requirements for 19-Wire Combination
Unilay Stranded Copper Conductors
Size, American (or
A B
Brown and
Wire D Wire D
1 2
Cross-Sectional Area Sharpe) Diameter, Diameter,
cmil sq mm Wire Gage mils mm mils mm
500 000 253.4 175.6 4.5 128.5 3.3
450 000 228.0 166.6 4.2 121.9 3.1
400 000 202.7 157.1 4.0 115.0 2.9
350 000 177.3 146.9 3.7 107.5 2.7
300 000 152.0 136.0 3.5 99.6 2.5
250 000 126.7 124.2 3.2 90.9 2.3
211 600 107.2 0000 114.2 2.4 83.6 2.1
167 800 85.0 000 101.7 2.6 74.5 1.9
133 100 67.4 00 90.6 2.3 66.3 1.7
105 600 53.5 0 80.7 2.0 59.1 1.5
83 690 42.4 1 71.8 1.8 52.6 1.3
66 360 33.6 2 64.0 1.6 46.8 1.2
52 620 26.7 3 57.0 1.4 41.7 1.1
41 740 21.1 4 50.7 1.3 37.1 0.9
33 090 16.8 5 45.2 1.1 33.1 0.8
26 240 13.3 6 40.2 1.0 29.4 0.7
20 820 10.5 7 35.8 0.9 26.2 0.7
16 510 8.4 8 31.9 0.8 23.4 0.6
13 090 6.6 9 28.4 0.7 20.8 0.5
10 380 5.3 10 25.3 0.6 18.5 0.5
6530 3.3 12 20.1 0.5 14.7 0.4
4110 2.1 14 15.9 0.4 11.7 0.3
2580 1.3 16 12.6 0.3 9.2 0.2
1620 0.8 18 10.0 0.3 7.3 0.2
1020 0.5 20 7.9 0.2 5.8 0.1
640 0.3 22 6.3 0.2 4.6 0.1
404 0.2 24 5.0 0.1 3.7 0.1
A
Equation Equation to calculate D :
Cross 2Sectional Area
Œ
16.2149
B
Equation Equation to calculate D : D × 0.732.
2 1
B787/B787M − 04 (2014)
4.2 Before stranding, the copper wire used shall meet all of the requirements of the following ASTM specifications that are
applicable to its type:
4.2.1 Specification B3.
4.2.2 Specification B33.
4.2.3 Specification B2.
4.2.4 Specification B1.
4.2.5 Specification B189.
4.2.6 Specification B246.
4.3 In combination unilay stranded conductors, the central core wire shall be made of the same type and temper as the layers,
unless otherwise specified.
5. Joints
5.1 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 50 ft (15.24 m) for hard and medium-hard
conductors, and 1 ft in a layer for soft conductors.
6. Lay
6.1 For combination unilay conductors the lay of a layer of wires shall be not less than 8 nor more than 16 times the outside
diameter of the outer layer.
6.2 Other lays for special purposes shall be furnished by special agreement between the manufacturer and the purchaser
(Explanatory Note 4).
6.3 The direction of lay shall be left-hand unless the direction of lay is specified otherwise by the purchaser.
7. Construction (Explanatory Note 3)
7.1 The cross-sectional areas, numbers, and diameters of wires in the various conductors shall conform to the requirements
prescribed in Table 1.
7.2 The diameters of the wires listed in Table 2 are nominal. In order to produce an essentially round 19-wire construction, the
outer 12-wire layer in the combination unilay product is comprised of 6 wires of the same diameter as the wires in the 7-wire core,
and 6 wires approximately 25 % smaller. The 2-wire sizes are alternated around the 7-wire core (Fig. 1).
TABLE 2 Diameters, Areas, and Masses of 19-Wire Combination Unilay Stranded Copper Conductors
Nominal Area Mass
Size of Conductor
A 2 2
cmil or AWG sq mm Nominal Diameter, in. Conductor, mm in. mm lbs/1000 ft lbs/mile g/m
500 000 253.4 0.784 19.914 0.392700 253.35 1544 8151 2297
450 000 228.0 0.744 18.878 0.353400 228.02 1389 7336 2067
400 000 202.7 0.701 17.805 0.314000 202.68 1235 6521 1838
350 000 177.3 0.656 16.662 0.274900 177.35 1081 5706 1609
300 000 152.0 0.607 15.418 0.235600 152.01 926.3 4891 1378
250 000 126.7 0.554 14.072 0.196300 126.68 771.9 4076 1149
0000 107.2 0.510 12.954 0.166200 107.22 653.3 3450 972.1
000 85.0 0.454 11.532 0.131800 85.02 518.1 2736 770.9
00 67.4 0.404 10.262 0.104500 67.44 410.9 2169 611.4
0 53.5 0.360 9.144 0.082910 53.51 325.8 1720 684.8
1 42.4 0.321 8.153 0.065730 42.41 258.4 1364 384.5
2 33.6 0.286 7.264 0.052120 33.62 204.9 1082 304.9
3 26.7 0.254 6.452 0.041330 26.77 162.5 858.1 241.8
4 21.1 0.226 5.740 0.032780 21.15 128.9 680.5 191.8
5 16.8 0.202 5.131 0.025990 16.77 102.2 539.6 152.1
6 13.3 0.179 4.547 0.020610 13.30 81.05 428.0 120.6
7 15.6 0.160 4.064 0.016350 10.55 64.28 339.4 95.65
8 8.4 0.143 3.632 0.012970 8.37 50.97 269.1 75.84
9 6.6 0.127 3.226 0.010280 6.63 40.42 213.4 60.14
10 5.3 0.113 2.870 0.008155 5.26 32.06 169.3 47.71
12 3.3 0.090 2.286 0.005130 3.31 20.16 106.5 30.00
14 2.1 0.071 1.803 0.003230 2.08 12.68 66.95 18.87
16 1.3 0.056 1.422 0.002030 1.31 7.974 42.10 11.87
18 0.8 0.045 1.143 0.001280 0.82 5.015 26.48 7.462
20 0.5 0.035 0.809 0.000804 0.52 3.154 16.65 4.693
22 0.3 0.028 0.703 0.000503 0.32 1.992 10.52 2.964
24 0.2 0.022 0.558 0.000317 0.20 1.249 6.59 1.859
A
To calculate the diameter, multiply the large wire diameter in Table 1 by 3 and add two times the small wire diameter.
Example: AWG 4/0 diameter = [(3(114.2) + 2 (83.6)] = 509.8
B787/B787M − 04 (2014)
8. Physical and Electrical Tests of Conductors Stranded of Soft Wires
8.1 Tests for the electrical properties of wires composing conductors made from soft or annealed copper wire, bare or coated,
shall be made before stranding.
8.2 Tests for the physical properties of soft or annealed copper wire, bare or coated, may be made upon the wires before
stranding or upon wires removed from the complete stranded conductor, but need not be made upon both. Care shall be taken to
avoid mechanical injury to wire removed from the conductor for the purpose of testing.
8.3 The physical properties of wire when tested before stranding shall conform to the applicable requirements of 4.2.
8.4 The physical properties of wires removed from the completed stranded conductor shall be permitted to vary from the
applicable requirements of 4.2 by the amounts as follows (Explanatory Note 5):
8.4.1 Average of Results Obtained on All Wires Tested—The minimum elongation required shall be reduced in numerical value
5 (for example, from 30 to 25 %) from the numerical requirements for the wire before stranding.
8.4.2 Results Obtained on Individual Wires—The elongation of individual wires shall be reduced in numerical value 15 from
the minimum requirements before stranding (that is, 10 in addition to the 5 allowed in 8.4.1), but in no case shall the elongation
of any individual wire be less than 5 %.
8.5 In the event that the requirements prescribed in 8.4.2 are met but those prescribed in 8.4.1 are not met, a retest shall be
permitted wherein all wires of the conductor shall be tested for the purpose of final determination of conformance to 8.4.
8.6 Elongation tests to determine compliance shall not be made on the conductor as a unit.
8.7 If a tinning or lead-alloy-coating test is required, it shall be made on the wires prior to stranding.
9. Physical and Electrical Tests of Conductors Stranded of Hard-Drawn or Medium-Hard Drawn Wires
9.1 Tests for the physical and electrical properties of wires composing conductors made from hard-drawn or medium-hard-
drawn wires, uncoated or coated, shall be made before but not after stranding.
9.2 At the option of the purchaser, tension and elongation tests on hard-drawn and medium-hard-drawn wires, uncoated or
coated, before stranding may be waived, and the completed hard-drawn and medium-hard-drawn conductors may be tested as a
unit. The breaking strength of the bare conductors so tested shall be at least 90 % of the total of the specified minimum breaking
strengths of the component wires. The maximum breaking strength of conductors made from medium-hard-drawn wires, uncoated
or coated, shall be not greater than the sum of the specified maximum breaking strengths of the component wires. The minimum
breaking strengths of wires shall be calculated using specified nominal diameters and specified minimum tensile strengths. The
maximum breaking strengths of wires shall be calculated using nominal diameters and specified maximum tensile strengths. The
free length between grips of the test specimen shall be not less than 24 in. (610 mm), and care shall be taken to ensure that the
wires in the conductor are evenly gripped during the test (Explanatory Note 6).
9.3 When requested by the purchaser at the time of placing the order, tension tests on hard-drawn and medium-hard-drawn
wires, uncoated or coated, before stranding or as a unit may be waived and tests made on wires removed from the completed
conductor. The test limits, based on a 10-in. (254-mm) gage length, for such tests shall be specified by the purchaser in the placing
of individual orders (Explanatory Note 5).
9.4 If a tinning test is required, it shall be made on the wires prior to stranding.
10. Density
10.1 For the purpose of calculating masses, cross sections, and so forth, the density of the copper shall be taken as 8.89
3 3
g/cm (0.32117 lb/in. ) at 20°C (Explanatory Note 7).
11. Mass and Resistance
11.1 The mass and electrical resistance of a unit length of stranded conductor are a function of the length of lay. The
approximate mass and electrical resistance may be determined using the standa
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