ASTM B33-10(2020)e1
(Specification)Standard Specification for Tin-Coated Soft or Annealed Copper Wire for Electrical Purposes
Standard Specification for Tin-Coated Soft or Annealed Copper Wire for Electrical Purposes
ABSTRACT
This specification covers tinned, round, soft, or annealed copper wire for electrical purposes. The tinned wire shall conformto the required tensile strength and elongation. Electrical resistivity shall be measured. The wire sizes shall be expressed as the diameter of the wire and shall be measured using micrometre caliper equipped with a vernier. The tin coating shall be continuous. The continuity of the wire shall be determined on representative samples taken before stranding or insulating. The continuity of tinning shall be determined by the hydrochlroic acid-sodium polysulfide test. The tin coating shall be firmly adherent to the surface of the copper. The adherence of coating on the wire shall be determined on representative samples taken before stranding or insulating. The adherence of coating shall be determined by the wrapping and immersion test.
SCOPE
1.1 This specification covers tin-coated, round, soft, or annealed copper wire for electrical purposes.
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 Exceptions—The SI values for density, resistivity, and volume 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
Relations
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.
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Designation:B33 −10 (Reapproved 2020)
Standard Specification for
Tin-Coated Soft or Annealed Copper Wire for Electrical
Purposes
This standard is issued under the fixed designation B33; 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.Asuperscript
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.
ε NOTE—Editorial corrections were made to 6.3.1.2, 6.4.1.2, and Explanatory Note 6 in January 2020.
1. Scope 2.2 Other Document:
NBS Handbook 100 Copper Wire Tables
1.1 This specification covers tin-coated, round, soft, or
annealed copper wire for electrical purposes.
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 Exceptions—The SI values for density, resistivity, and
3.1.3 Type of copper, if special (see 4.2),
volume 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 packaging 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. Material
priate safety, health, and environmental practices and deter-
mine the applicability of regulatory limitations prior to use. 4.1 Tin for Coating—The tin used for coating shall be
commercially pure (Explanatory Note 1). For purposes of this
1.4 This international standard was developed in accor-
dance with internationally recognized principles on standard- specification, the tin shall be considered commercially pure if
the total of other elements, exclusive of copper, does not
ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom- exceed 1 %. Notwithstanding the previous sentence, chemical
mendations issued by the World Trade Organization Technical analysisofthetincoatingorofthetinusedforcoatingshallnot
Barriers to Trade (TBT) Committee. be required under this specification. Adequacy of the tin
coatingisassuredbythecontinuityofcoatingandadherenceof
2. Referenced Documents
coating requirements (see 5.4 and 5.5, respectively).
2.1 ASTM Standards:
4.2 Copper-Base Metal—The base metal shall be copper of
B49 Specification for Copper Rod for Electrical Purposes
such quality and purity that the finished product shall have
B193 Test Method for Resistivity of Electrical Conductor
properties and characteristics prescribed in this specification.
Materials
NOTE 1—Specification B49 defines copper suitable for use.
B258 Specification for Standard Nominal Diameters and
4.3 Copper bars of special qualities, forms, or types, as may
Cross-Sectional Areas of AWG Sizes of Solid Round
be agreed upon between the manufacturer and the purchaser,
Wires Used as Electrical Conductors
and which will conform to the requirements prescribed in this
specification, may also be used.
This specification is under the jurisdiction of ASTM Committee B01 on
Electrical Conductors and is the direct responsibility of Subcommittee B01.04 on 5. General Requirements (See Section 8)
Conductors of Copper and Copper Alloys.
5.1 Tensile Strength and Elongation (Explanatory Note 2
Current edition approved Jan. 1, 2020. Published January 2020. Originally
approved in 1919. Last previous edition approved in 2014 as B33 – 10 (2014). DOI: and Note 3)—The tinned wire shall conform to the require-
10.1520/B0033-10R20E01.
ments for elongation prescribed in Table 1. No requirements
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
Standards volume information, refer to the standard’s Document Summary page on Available from National Technical Information Service (NTIS), 5301 Shawnee
the ASTM website. 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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B33−10 (2020)
TABLE 1 Tensile Requirements TABLE 2 Electrical Resistivity Requirements
Diameter Area at 20°C Nominal Diameter Resistivity at 20°C
Elongation
2 2
in 10 in. in. mm Ω·lb/mile Ω·g/m
(250 mm),
0.460 to 0.290, incl 11.7 to 7.4, incl 896.15 0.15695
2 2
in. mm cmil in. mm %min
Under 0.290 to 0.103, incl Under 7.4 to 2.6, incl 900.77 0.15776
0.4600 11.684 211600 0.1662 107.0 30
Under 0.103 to 0.0201, incl Under 2.6 to 0.51, incl 910.15 0.15940
0.4096 10.404 167800 0.1318 85.0 30 Under 0.0201 to 0.0111 incl Under 0.51 to 0.28, incl 929.52 0.16279
0.3648 9.266 133100 0.1045 67.4 30
Under 0.0111 to 0.0030, incl Under 0.28 to 0.076, incl 939.51 0.16454
0.3249 8.252 105600 0.08291 53.5 30
0.2893 7.348 83690 0.06573 42.4 25
0.2576 6.543 66360 0.05212 33.6 25
0.2294 5.827 52620 0.04133 26.7 25
(0.0025 mm). The tin-coated wire shall not vary from the
0.2043 5.189 41740 0.03278 21.2 25
specified diameter by more than the amounts prescribed in
Table 3.
0.1819 4.620 33090 0.02599 16.8 25
0.1620 4.115 26240 0.02061 13.3 25
5.4 Continuity of Coating—The tin coating shall be continu-
0.1443 3.665 20820 0.01635 10.6 25
0.1285 3.264 16510 0.01297 8.37 25 ous. The continuity of coating on the wire shall be determined
on representative samples taken before stranding or insulating.
0.1144 2.906 13090 0.01028 6.63 25
The continuity of tinning shall be determined by the hydro-
0.1019 2.588 10380 0.008155 5.26 20
0.0907 2.304 8230 0.00646 4.17 20
chloric acid-sodium polysulfide test in accordance with 6.3.
0.0808 2.052 6530 0.00513 3.31 20
5.5 Adherence of Coating—The tin coating shall be firmly
0.0720 1.829 5180 0.00407 2.63 20
adherent to the surface of the copper. The adherence of coating
0.0641 1.628 4110 0.00323 2.08 20
on the wire shall be determined on representative samples
0.0571 1.450 3260 0.00256 1.65 20
0.0508 1.290 2580 0.00203 1.31 20 taken before stranding or insulating. The adherence of coating
shall be determined by the wrapping and immersion test in
0.0453 1.151 2050 0.00161 1.04 20
accordancewith6.4for0.0320in.(0.813mm)andlargersizes.
0.0403 1.024 1620 0.00128 0.823 20
0.0359 0.912 1290 0.00101 0.653 20
5.6 Joints—Necessary joints in the completed wire and in
0.0320 0.813 1020 0.000804 0.519 20
the wire and rods prior to final drawing shall be made in
0.0285 0.724 812 0.000638 0.412 20
accordance with the best commercial practice.
0.0253 0.643 640 0.000503 0.324 20
5.7 Finish—The coating shall consist of a smooth continu-
0.0226 0.574 511 0.000401 0.259 20
0.0201 0.511 404 0.000317 0.205 15
ouslayer,firmlyadherenttothesurfaceofthecopper.Thewire
shall be free of all imperfections not consistent with the best
0.0179 0.455 320 0.000252 0.162 15
commercial practice.
0.0159 0.404 253 0.000199 0.128 15
0.0142 0.361 202 0.000158 0.102 15
0.0126 0.320 159 0.000125 0.080 15
6. Test Methods
0.0113 0.287 128 0.000100 0.065 15
6.1 Tensile Strength and Elongation (Explanatory Note 5):
0.0100 0.254 100 0.0000785 0.051 10
6.1.1 No test for tensile strength shall be required.
0.0089 0.226 79.2 0.0000622 0.040 10
6.1.2 The elongation of wire with a nominal diameter
0.0080 0.203 64.0 0.0000503 0.032 10
greater than 0.0808 in. (2.052 mm) shall be determined as the
0.0071 0.180 50.4 0.0000396 0.026 10
permanent increase in length due to the breaking of the wire in
0.0063 0.160 39.7 0.0000312 0.020 10
tension.The elongation shall be measured between gage marks
0.0056 0.142 31.4 0.0000246 0.016 10
0.0050 0.127 25.0 0.0000196 0.013 10
placed originally 10 in. (254 mm) apart upon the test specimen
and expressed in percent of the original length.
0.0045 0.114 20.3 0.0000159 0.010 10
6.1.3 The elongation of wire with a nominal diameter equal
0.0040 0.102 16.0 0.0000126 0.0081 10
0.0035 0.089 12.3 0.00000962 0.0062 10
to or less than 0.0808 in. (2.053 mm) may be determined as
0.0031 0.079 9.61 0.00000755 0.0049 10
describedaboveorbymeasurementsmadebetweenthejawsof
the testing machine. When measurements are made between
the jaws, the zero length shall be the distance between the jaws
at the start of the tension test and be as near 10 in. (254 mm)
for tensile strength are specified. For wire whose nominal
as practicable. The final length shall be the distance between
diameter is more than 0.001 in. (0.025 mm) greater than a size
the jaws at the time of rupture. The fracture shall be between
listed in Table 1, but less than that of the next larger size, the
requirements of the next larger size shall apply.
5.2 Resistivity (Explanatory Note 1 and Note 4)—The elec-
TABLE 3 Permissible Variations in Diamter
trical resistivity of tinned wire at a temperature of 20°C shall
Permissible Variations in Diameter
Nominal Diameter of Wire
not exceed the values prescribed in Table 2.
in. mm
in. mm plus minus plus minus
5.3 Dimensions and Permissible Variations (Explanatory
Under 0.0100 Under 0.25 0.0003 0.00010 0.0076 0.0025
Note 2)—The wire sizes shall be expressed as the diameter of
0.0100 and over 0.25 and over 3 % 1 % 3 % 1 %
thewireindecimalfractionsofaninchtothenearest0.0001in.
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B33−10 (2020)
gage marks or jaws of the testing machine, depending on considered exhausted if it fails to blacken a piece of clean
method used, and not closer than 1 in. (25.4 mm) to either gage copper as described above.
mark or jaw.
6.3.3 Procedure:
6.3.3.1 Immersion of Specimens—Immerse a length of at
6.2 Dimensional Measurements—Dimensional measure-
least 4- ⁄2 in. (114 mm) from each of the clean specimens, in
ments shall be made with a micrometer caliper equipped with
accordance with the following cycles, in test solutions main-
a vernier graduated in 0.0001 in. (0.0025 mm). Measurements
tained at a temperature between 15.6 and 21°C (60 and 70°F):
shall be made on at least three places on each unit selected for
(1) Immerse the specimen for 1 min in the HCl solution
this test. If accessible, one measurement shall be taken on each
described in 6.3.2, wash, and wipe dry; (2) immerse the
end and one near the middle. The average of the three
specimen for 30 s in the sodium polysulfide solution described
measurements shall determine compliance with the require-
in 6.3.2, wash, and wipe dry; (3) immerse the specimen for 1
ments.
min in the HCl solution, wash, and dry; (4) immerse the
6.3 Continuity of Coating:
specimenfor30sinthesodiumpolysulfidesolution,wash,and
6.3.1 Specimens:
wipe dry.
6.3.1.1 Length of Specimens—Test specimens shall have a
6.3.3.2 Washing Specimens—After each immersion, imme-
lengthofabout6in.(152mm).Theyshallbetaggedormarked
diately wash the specimens thoroughly in clean water and wipe
tocorrespondwiththecoil,spool,orreelfromwhichtheywere
dry with a clean, soft cloth.
cut.
6.3.3.3 Examination of Specimens—After immersion and
6.3.1.2 Treatment of Specimens—The specimens shall be
washing, examine the specimens to ascertain if copper exposed
thoroughly cleaned by immersion in a suitable organic solvent
through openings in the tin coating has been blackened by
for at least 3 min; then removed and wiped dry with a clean,
action of the sodium polysulfide. The specimens shall be
soft cloth (Warning—see Explanatory Note 6).The specimens
considered to have failed if, by such blackening, exposed
thus cleaned shall be kept wrapped in a clean, dry cloth until
copper is revealed. No attention shall be paid to blackening
tested. That part of the specimen to be immersed in the test
within 0.5 in. (12.7 mm) of the cut end. A grayish brown
solution shall not be handled. Care shall be taken to avoid
appearance of the coating shall not constitute failure.
abrasion by the cut ends.
6.4 Adherence of Coating:
6.3.2 Special Solutions Required:
6.4.1 Specimens:
6.3.2.1 Hydrochloric Acid Solution (HCl) (sp gr 1.088)—
Commercial HCl (sp gr 1.12) shall be diluted with distilled 6.4.1.1 Length of Specimens—Test specimens shall be ap-
proximately 12 in. (305 mm) in length and shall be tagged or
water to a specific gravity of 1.088 measured at 15.6°C (60°F).
Aportion of HCl solution having a volume of 180 mLshall be marked to correspond with the coil, spool, or reel from which
they are cut.
considered to be exhausted when the number of test specimens
prescribed in Table 4 of a size as indicated in 6.3.3 have been 6.4.1.2 Treatment of Specimens—The specimens shall be
thoroughly cleaned, if required, by immersion in a suitable
immersed in it for two cycles.
6.3.2.2 Sodium Polysulfide Solution (sp gr 1.142) (Ex- organic solvent for at least 3 min, then removed and dried
planatory Note 7)—A concentrated solution shall be made by (Warning—See Explanatory Note 6). The specimens thus
dissolving sodium sulfide cp crystals in distilled water until the cleaned shall be kept wrapped in a clean dry cloth until tested.
solutionissaturatedatabout21°C(70°F),andaddingsufficient That part of the specimens to be immersed in the test solution
flowers of sulfur (in excess of 250 g/L of solution) to provide shall not be handled. Care shall be taken to avoid abrasion of
complete saturation, as shown by the presence in the solution the surface to be subjected to test. Wire of sizes 0.005 in. (0.13
of an excess of sulfur after the solution has been allowed to mm) and smaller may be cleaned after wrapping around the
stand for at least 24 h. The test solution shall be made by mandrel.
diluting a portion of the concentrated solution with distilled 6.4.2 Procedure:
water to a specific gravity of 1.135 to 1.145 at 15.6°C (60°F).
6.4.2.1 Wrapping—Slowly wrap the test specimen in a
The sodium polysulfide test solution should have sufficient
suitable manner in an open helix around a polished mandrel
strengthtoblackenthoroughlyapieceofcleanuntinnedcopper
having rounded ends and a diameter not to exceed four times
wire in 5 s. The test solution used for testing samples shall be
the nominal diameter of the specimen. Take care not to stretch
the specimen during the wrapping operation. The spacing of
the consecutive turns shall be approximately equal to the
diameterofthewire.Forsizes0.021in.(0.53mm)andsmaller,
TABLE 4 Limiting Number of Test Specimens fo
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