ASTM B228 Copper Clad Steel Wire for Grounding Purpose
good electric conductivity.
strong capability of anti-oxidation
Branded products with high quality
1.1 This specification covers bare concentric-lay-stranded
conductors made from bare round copper-clad steel wires for
general use for electrical purposes.
1.2 For the purpose of this specification, conductors are
classified as follows: Grade 40 HS, Grade 30 HS, and Grade 30
1.3 The values stated in inch-pound units are to be regarded
as the standard. The values given in parentheses are in SI units.
2. Referenced Documents
2.1 The following documents of the issue in effect on the
date of material purchase form a part of this specification to the
extent referenced herein:
2.2 ASTM Standards:
B 227 Specification for Hard-Drawn Copper-Clad Steel
B 354 Terminology Relating to Uninsulated Metallic Electrical
2.3 ANSI Standards:
C 42 Definitions of Electrical Terms3
2.4 National Institute of Standards and Technology:
NBS Handbook 100—Copper Wire Tables4
3. Ordering Information
3.1 Orders for material under this specification shall include
the following information:
3.1.1 Quantity of each size and grade;
3.1.2 Conductor size: approximate diameter in fractions of
an inch, or number and AWG size of individual wires (Section
7 and Table 1);
3.1.3 Grade (see 1.2 and Table 1);
3.1.4 Direction of lay of outer layer, if other than left-hand
3.1.5 When physical tests shall be made (see 8.2);
3.1.6 Package size (see 13.1);
3.1.7 Special package marking, if required (Section 12);
3.1.8 Lagging, if required (see 13.2); and
3.1.9 Place of inspection (Section 14).
3.2 In addition, Supplementary Requirements shall apply
only when specified by the purchaser in the inquiry, contract, or
purchase order for direct procurement by agencies of the U. S.
Government (S1, S2, and S3).
4. Material for Wires
4.1 The purchaser shall specify the grade of wire to be used
in the conductor.
4.2 Before stranding, the copper-clad steel wire shall meet
all the requirements of Specification B 227.
4.3 All wires in the conductor shall be of the same grade and
5.1 Joints or splices may be made in the finished individual
copper-clad steel wires composing concentric-lay-stranded
conductors, using more than three wires provided that such
joints or splices have a protection equivalent to that of the wire
itself and that they do not decrease the strength of the finished
stranded conductor below the minimum breaking strength
shown in Table 1. Such joints or splices shall be not closer than
50 ft (15 m) to any other joint in the same layer in the
conductor (Note 1).
NOTE 1—Joints or splices in individual copper-clad steel wires in their
finished size are made by electrical butt welding. Two types of joints are
used and are described as follows:
(a) Weld-Annealed Joints—After butt welding, the wire is annealed for
a distance of approximately 5 in. (127 mm) on each side of the weld. The
weld is then protected from corrosion with a snug fitting seamless copper
sleeve which extends at least 3⁄8 in. (9.5 mm) on each side of the weld and
which is thoroughly sealed to the wire with solder. The wall thickness of
the sleeve is at least 10 % of the radius of the wire.
This joint has a tensile strength of approximately 60 000 psi (415 MPa).
This is less than the strength of the individual wires, but an allowance is
made for this in the rated strength of the conductor as a whole. The
completed conductor when containing such joints is required to have the
full rated strength.
This type of joint is but slightly larger than the wire itself and is
applicable for 7, 12, and 19-wire stranded conductors.
(b) Compression-Weld Joints—Compression-weld joints differ from
weld-annealed joints in that the wire is not annealed after the butt-welding
operation but is reinforced with a hard-drawn, seamless, silicon-tin bronze
sleeve which is applied by means of a hydraulic compressor over the weld.
This sleeve is covered with solder so as to completely seal the ends. These
sleeves have a wall thickness of 25 to 50 % of the radius of the wire,
depending on the wire size. Their use is usually limited to 3-wire
conductors where the relatively large diameter is not objectionable. This
joint develops the full strength of the wire.
6.1 For 3-wire conductors the preferred lay is 161⁄2 times the
outside diameter, but the lay shall not be less than 14 times nor
more than 20 times this diameter.
6.2 For 7- and 19-wire conductors the preferred lay is 131⁄2
times the diameter of that layer, but the lay shall not be less
than 10 nor more than 16 times this diameter.
6.3 The direction of lay of the outer layer shall be left-hand
unless the direction of lay is specified otherwise by the
6.4 The direction of lay shall be reversed in consecutive
6.5 All wires in the conductor shall lie naturally in their true
positions in the completed conductor. They shall tend to remain
in position when the conductor is cut at any point and shall
permit restranding by hand after being forcibly unraveled at the
end of the conductor.
7.1 The numbers and diameters of the wires in the
concentric-lay-stranded conductors shall conform to the requirements
prescribed in Table 1 (Note 2 ).
NOTE 2—For definitions of terms relating to conductors, reference
should be made to (1) ANSI C42.35-latest revision and (2) Terminology
8. Physical and Electrical Tests
8.1 Tests for physical and electrical properties of wires
composing concentric-lay-stranded conductors made from
copper-clad steel wire shall be made before stranding.
8.2 At the option of the purchaser, tension and elongation
tests before stranding may be waived and the complete
conductors may be tested as a unit. The breaking strength of the
conductors so tested shall be not less than that required in Table
8.3 Where breaking strength tests are required on the
finished conductor, they shall be made on representative
samples, not less than 4 ft (1.22 m) in length. For lots of 10 000
lb (4540 kg) or less, two samples shall be taken from separate
reels or coils in the lot except that but one sample shall be
required where the total amount of conductor is 5000 ft (1525
m) or less. For quantities over 10 000 lb, one sample for each
10 000 lb or fraction thereof, shall be taken, but the minimum
number of samples shall be three.
8.4 Specimens of the completed conductor shall be tested in
a tensile testing machine equipped with jaws suitable for
gripping of the conductor or equipped for holding properly
socketed specimens. Any test in which the result is below the
stated value and which is obviously caused by improper
socketing of the specimen, or due to the break occurring in or
at the gripping jaws of the machine, shall be disregarded and
another sample from the same coil or reel shall be tested.
9.1 For the purpose of calculating mass per unit length
(Note 3), cross sections, etc., the density of the copper-clad
steel wire shall be taken as shown in Table 2 (Note 4).
NOTE 3—The term mass per unit length is used in this specification as
being more technically correct replaces the term “weights.”
NOTE 4—The value of density of copper-clad steel is an average value
which has been found to be in accordance with usual values encountered
in practice. Equivalent expressions of density at 20°C are given in Table
10. Mass and Resistance
10.1 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 standard increments shown in Table 3. When greater
accuracy is desired, the increment based on the specific lay of
the conductor may be calculated (Note 5).
NOTE 5—The increment of mass or electrical resistance of a completed
concentric-lay-stranded conductor (k) in percent is
k 5 100~m 2 1!
where m is the stranding factor, and is also the ratio of the mass or
electrical resistance of a unit length of stranded conductor to that of a solid
conductor of the same cross-sectional area or of a stranded conductor with
infinite length of stranding, that is, all wires parallel to the conductor axis.
The stranding factor m for the completed stranded conductor is the
numerical average of the stranding factors for each of the individual wires
in the conductor, including the straight core wire, if any (for which the
stranding factor is unity). The stranding factor (mind) for any given wire in
a concentric-lay-stranded conductor is
mind 5=1 1 ~9.8696/n2!
where n = length of lay/diameter of helical path of the wire. The
derivation of the above is given in NBS Handbook 100.
11. Variation in Area
11.1 The area of cross section of the completed conductor
shall be not less than 98 % of the area specified. The area 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
NOTE 6—For the convenience of the users of this specification, Table 4
has been prepared giving areas, resistances per 1000 ft and mass per 1000
ft and per mile, of the various constructions referred to in Table 1.
12.1 Unless otherwise specified in the contract or purchase
order, the manufacturer shall be responsible for the performance
of all inspection and test requirements specified.
12.2 All inspections and tests shall be made at the place of
manufacture unless otherwise especially agreed to between the
manufacturer and the purchaser at the time of the purchase.
12.3 The manufacturer shall afford the inspector representing
the purchaser all reasonable manufacturer’s facilities necessary
to ensure that the material is being furnished in
accordance with this specification.
13. Packaging and Package Marking
13.1 Package sizes for conductors shall be agreed upon by
the manufacturer and the purchaser in the placing of individual
13.2 The conductors shall be protected against damage in
ordinary handling and shipping. If heavy wood lagging is
required, it shall be specified by the purchaser at the time of the
13.3 The net mass, length (or lengths, and number of
lengths, if more than one length is included in the package),
size, grade of conductor, purchase order number, and any other
marks required by the purchase order shall be marked on a tag
attached to the end of the conductor inside of the package. The
same information together with the manufacturer’s serial
number (if any) and all shipping marks required by the
purchaser shall appear on the outside of each package.
14.1 clad steel electrical conductor; concentric-lay-stranded
copper-clad steel electrical conductor; copper electrical
conductor—copper-clad steel; copper electrical conductor—
stranded; copper-clad steel electrical conductor; electrical
1. grounding purpose
2. electrical railway system
3. overhead drop cable
4. tower lead cable