ASTM D470-99

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An American National Standard
Designation:D470–99
Standard Test Methods for
Crosslinked Insulations and Jackets for Wire and Cable
This standard is issued under the fixed designation D470; 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 (e) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the Department of Defense.
1. Scope
U-Bend Discharge Test 121 to 125
Water Absorption Test 65 to 71
1.1 These test methods cover procedures for testing
Water Absorption Test, Accelerated 72 to 86
crosslinked insulations and jackets for wire and cable. To
Water Absorption Test on Fibrous Coverings 105 to 110
determine the test to be made on the particular insulation or
2. Referenced Documents
jacket, reference should be made to the product specification
2.1 ASTM Standards:
for that type. These test methods do not apply to the class of
D149 Test Method for Dielectric Breakdown Voltage and
products known as flexible cords.
Dielectric Strength of Solid Electrical Insulating Materials
1.2 This standard does not purport to address all of the
at Commercial Power Frequencies
safety problems, if any, associated with its use. It is the
D150 Test Methods for AC Loss Characteristics and Per-
responsibility of the user of this standard to establish appro-
mittivity (Dielectric Constant) of Solid Electrical Insulat-
priate safety and health practices and determine the applica-
ing Materials
bilityofregulatorylimitationspriortouse.Forspecifichazards
D257 Test Methods for D-C Resistance or Conductance of
see Section 4.
Insulating Materials
1.3 Whenever two sets of values are presented, in different
D412 Test Methods for Vulcanized Rubber and Thermo-
units, the values in the first set are the standard, while those in
plastic Rubbers and Thermostatic Elastomers—Tension
the parentheses are for information only.
D454 Test Method for Rubber Deterioration by Heat and
1.4 In many instances the insulation or jacket cannot be
Air Pressure
tested unless it has been formed around a conductor or cable.
D572 Test Method for Rubber Deterioration by Heat and
Therefore, tests are done on insulated or jacketed wire or cable
Oxygen
in these test methods solely to determine the relevant property
D573 Test Method for Rubber—Deterioration in an Air
of the insulation or jacket and not to test the conductor or
Oven
completed cable.
D1193 Specification for Reagent Water
1.5 The procedures appear in the following sections:
D1711 Terminology Relating to Electrical Insulation
Sections
AC and DC Voltage Withstand Tests 22 to 29
D2132 Test Method for Dust-and-Fog Tracking and Ero-
Capacitance and Dissipation Factor Tests 38 to 44 2
sion Resistance of Electrical Insulating Materials
Cold Bend 128
D3755 Test Method for Dielectric Breakdown Voltage and
Cold Bend, Long-Time Voltage Test on Short Specimens 51 to 57
Double AC Voltage Test on Short Specimens 45 to 50 Dielectric Strength of Solid Electrical Insulating Materials
Electrical Tests of Insulation 17 to 64 5
Under Direct-Voltage Stress
Heat Distortion Test 127
D5025 Specification for a Laboratory Burner Used for
Horizontal Flame Test 100 to 104
Insulation Resistance Tests on Completed Cable 30 to 37
Small-Scale Burning Tests on Plastic Materials
Mineral Filler Content, Determination of 111 to 115
D5207 Practice for Calibration of 20 and 125 mm Test
Ozone Resistance Test 87 to 99
Flames for Small-Scale Burning Tests on Plastic Materi-
Partial-Discharge Test 58 to 64
Physical Tests of Insulation and Jacket Compounds 5 to 16
als
Surface Resistivity Test 116 to 120
D 5423 Specification for Forced-Convection Laboratory
Track Resistance Test 129 to 132
Ovens for Evaluation of Electrical Insulation
These test methods are under the jurisdiction of ASTM Committee D-9 on
Electrical and Electronic Insulating Materials and are the direct responsibility of Annual Book of ASTM Standards, Vol 10.01.
Subcommittee D09.18 on Solid Insulations, Non-Metallic Shieldings, and Cover- Annual Book of ASTM Standards, Vol 09.01.
ings for Electrical and Telecommunications Wire and Cables. Annual Book of ASTM Standards, Vol 11.01.
Current edition approved March 10, 1999. Published June 1999. Originally Annual Book of ASTM Standards, Vol 10.02.
published as D470–37 T. Last previous edition D470–93. Annual Book of ASTM Standards, Vol 08.03.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D470–99
2.2 ICEA Standard: agencies and are usually based upon recommendations made
T-24-380 Guide for Partial-Discharge Procedure by the American Conference of Governmental Industrial Hy-
gienists. Ozoneislikelytobepresentwhenevervoltagesexist
3. Terminology
which are suffıcient to cause partial, or complete, discharges in
air or other atmospheres that contain oxygen. Ozone has a
3.1 Definitions—For definitions of terms used in these test
distinctive odor which is initially discernible at low concen-
methods, refer to Terminology D1711.
trations but sustained inhalation of ozone can cause temporary
3.2 Definition of Term Specific to this Standard:
loss of sensitivity to the scent of ozone. Because of this it is
3.2.1 aging (act of), n—exposure of material to air or oil at
important to measure the concentration of ozone in the
a temperature and time as specified in the relevant material
atmosphere, using commercially available monitoring devices,
specification for that material.
whenever the odor of ozone is persistently present or when
3.3 Symbol:
ozone generating conditions continue. Use appropriate means,
3.3.1 kcmil—thousands of circular mils.
such as exhaust vents, to reduce ozone concentrations to
4. Hazards
acceptable levels in working areas. See Section 90.
4.1 Mercury:
PHYSICAL TESTS OF INSULATIONS AND
4.1.1 Mercury metal vapor poisoning has long been recog-
JACKETS
nized as a hazard in industry. The exposure limits are set by
governmental agencies and are usually based upon recommen-
5. Significance and Use
dations made by the American Conference of Governmental
Industrial Hygienists. The concentration of mercury vapor
5.1 Physical tests, properly interpreted, provide information
over spills from broken thermometers, barometers, and other with regard to the physical properties of the insulation or
instruments using mercury can easily exceed these exposure
jacket. The physical test values give an approximation of how
limits. Mercury, being a liquid with high surface tension and the insulation will physically perform in its service life.
quite heavy, will disperse into small droplets and seep into
Physical tests may provide data for research and development,
cracks and crevices in the floor. This increased area of engineeringdesign,qualitycontrol,andacceptanceorrejection
exposure adds significantly to the mercury vapor concentration
under specifications.
in air. The use of a commercially available emergency spill kit
is recommended whenever a spill occurs. Mercury vapor
6. Physical Tests
concentration is easily monitored using commercially avail-
6.1 Physical tests shall include determination of the follow-
able sniffers. Make spot checks periodically around operations
ing:
where mercury is exposed to the atmosphere. Make thorough
6.1.1 Tensile strength,
checks after spills. See 8.3.2 and 8.3.3.
6.1.2 Tensile stress,
4.2 High Voltage:
6.1.3 Ultimate elongation,
4.2.1 Lethal voltages may be present during these tests. It is
6.1.4 Permanent set,
essential that the test apparatus, and all associated equipment
6.1.5 Accelerated aging,
that may be electrically connected to it, be properly designed
6.1.6 Tear resistance,
and installed for safe operation. Solidly ground all electrically
6.1.7 Effects of oil immersion, and
conductive parts that any person might come in contact with
6.1.8 Thickness of insulations and jackets.
during the test. Provide means for use at the completion of any
test to ground any parts which: were at high voltage during the
7. Sampling
test;mayhaveacquiredaninducedchargeduringthetest;may
7.1 Number of Samples—Unless otherwise required by the
retain a charge even after disconnection of the voltage source.
detailed product specification, wire and cable shall be sampled
Thoroughly instruct all operators in the proper way to conduct
for the physical tests, other than the tests for insulation and
tests safely. When making high voltage tests, particularly in
jacket thickness, as follows:
compressed gas or in oil, the energy released at breakdown
7.1.1 Sizes Less than 250 kcmil (127 mm )—One sample
may be suffıcient to result in fire, explosion, or rupture of the
shall be selected for each quantity ordered between 2000 and
test chamber. Design test equipment, test chambers, and test
50 000 ft (600 and 15 000 m) of wire or cable and one
specimens so as to minimize the possibility of such occurrences
additional sample for each additional 50000 ft. No sample
and to eliminate the possibility of personal injury.SeeSections
shall be selected from lots of less than 2000 ft.
20, 27, 33, 42, 48, 54, 62, 68, 76, 118, 123 and 130.
7.1.2 Sizes of 250 kcmil (127 mm ) and Over—One sample
4.3 Ozone:
shall be selected for each quantity ordered between 1000 and
4.3.1 Ozone is a physiologically hazardous gas at elevated
25000ft(300and7600m)ofwireorcableandoneadditional
concentrations. The exposure limits are set by governmental
sample for each additional 25000 ft. No sample shall be
selected from lots of less than 1000 ft.
7.2 Size of Samples—Samples shall be at least 6 ft (2 m) in
Available from the Insulated Cable Engineers Assoc., P.O. Box 440, South 2
length when the wire size is less than 250 kcmil (127 mm ),
Yarmouth, MA 02664.
andatleast3ft(1m)inlengthwhenthewiresizeis250kcmil
American Conference of Governmental and Industrial Hygienists, 6500 Glen-
way Ave., Building D-7, Cincinnati, OH 45211. or over.
D470–99
8. Test Specimens the mercury. Removal of the insulation may also be facilitated
by stretching the conductor to the breaking point in a tensile-
8.1 Number of Specimens—From each of the samples se-
strength machine.
lected in accordance with Section 7, test specimens shall be
8.3.3 Caution—Mercury is a hazardous material. See 4.1.
prepared as follows:
Care should be exercised to keep mercury from the hands.The
Number of Test
use of rubber gloves is recommended for handling specimens
Specimens
For Determination of Initial Properties (Unaged):
as in 8.3.2.
Tensile strength, tensile stress, and ultimate elongation 3
8.4 Specimens of Thin-Jacketed Insulation—In the case of
Permanent set 3
wires or cables having a thin jacket crosslinked directly to the
For Aging Tests:
Air pressure, heat, or oxygen pressure 3
insulation, it is usually necessary to prepare die-cut specimens
Air oven 3
of the jacket and insulation. Make an effort to separate the
For Oil Immersion 3
jacket from the insulation by slitting the covering through to
Onespecimenofeachthreeshallbetestedandtheothertwo
the conductor and pulling the jacket and insulation apart by
specimensheldinreserve,exceptthatwhenonlyonesampleis
pliers. (This procedure may be facilitated by immersing the
selected all three specimens shall be tested and the average of
sample in hot water for a few minutes just prior to pulling off
the results reported. For the tear test, six individual specimens
thejacket.)Ifthejacketcannotberemoved,preparespecimens
as described in 8.5 shall be used.
by buffing. Equip the buffing apparatus with a cylindrical table
8.2 SizeofSpecimens—Inthecaseofwireandcablesmaller
arrangedsothatitcanbeadvancedverygradually.Removethe
than AWG 6 (13.3 mm ) having an insulation thickness less
conductor from two short lengths of wire by slitting the
than 0.090 in. (2.29 mm), the test specimen may be the entire
covering. Stretch one length of covering into the clamps of the
section of the insulation. When the full cross section is used,
buffing apparatus so that it lies flat, with the jacket toward the
the specimens shall not be cut longitudinally. In the case of
wheel. The jacket is buffed off, with due care not to buff any
wire and cable ofAWG 6 and larger, or in the case of wire and
further than necessary, or overheat the material. Repeat the
cable smaller than AWG 6 having an insulation thickness
process with the other length of covering, except that the
greater than 0.090 in., specimens approximately square in
insulation is buffed off. Die-cut specimens may be prepared
section with a cross section not greater than 0.025 in. (16
from the buffed pieces after they have been allowed to recover
mm ) shall be cut from the insulation. In extreme cases, it may
foratleast30min.(Inthecaseofspecimensfromsmallwires,
be necessary to use a segmental specimen.
itmaybenecessarytouseadiehavingaconstrictedportion ⁄8
8.2.1 The test specimens shall be approximately 6 in. (150
in.(3.18mm)wide.)Jacketswithathicknessoflessthan0.030
mm) in length. Specimens for tests on jackets shall be taken
in. (0.76 mm) shall not be tested.
fromthecompletedwireorcableandcutparalleltotheaxisof
8.5 Specimen for the Tear Test—Cut the specimen with a
the wire or cable. With the exception of the tear tests, the test
sharp knife or die. After irregularities, corrugations, and
specimenshallbeeitherasegmentorsectorcutwithasuitable
reinforcing cords or wires have been removed, the test speci-
sharp instrument or a shaped specimen cut out with a die and
men shall conform to the dimensions shown in Fig. 1. The
shall have a cross-sectional area not greater than 0.025 in. (16
thickness of the test specimen shall be not greater than 0.150
mm )afterirregularities,corrugations,andreinforcingcordsor
in. (3.81 mm) and not less than 0.040 in. (1.02 mm). Split the
wires have been removed by buffing.
specimen longitudinally with a new razor blade to a point
8.3 Preparation of Specimens:
0.150 in. from the wider end.
8.3.1 The test specimen is to have no surface incisions and
8.6 Condition and Age—In accordance with Section 7, take
be as free as possible from other imperfections. Remove
samples of the insulated wire and cable for physical and
surface irregularities, such as corrugations due to stranding,
accelerated aging tests after crosslinking. Perform tests be-
etc., so that the test specimen will be smooth and of uniform
tween 24 h and 60 days after crosslinking unless agreed to by
thickness.
themanufacturer.Donotheat,immerseinwater,orsubjectthe
8.3.2 The removal of the insulation can be greatly acceler-
specimens
...