1、Designation: D470 13Standard Test Methods forCrosslinked Insulations and Jackets for Wire and Cable1This standard is issued under the fixed designation D470; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision
2、. A number 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.1. Scope1.1 These test methods cover procedures for testi
3、ng cross-linked insulations and jackets for wire and cable. To determinethe test to be made on the particular insulation or jacket, referto the product specification for that type. These test methods donot apply to the class of products known as flexible cords.1.2 In many instances the insulation or
4、 jacket cannot betested unless it has been formed around a conductor or cable.Therefore, tests are done on insulated or jacketed wire or cablein these test methods solely to determine the relevant propertyof the insulation or jacket and not to test the conductor orcompleted cable.1.3 The procedures
5、appear in the following sections:SectionsAC and DC Voltage Withstand Tests 22 to 29Capacitance and Dissipation Factor Tests 38 to 44Cold Bend 128Cold Bend, Long-Time Voltage Test on Short Specimens 51 to 57Double AC Voltage Test on Short Specimens 45 to 50Electrical Tests of Insulation 17 to 64Heat
6、Distortion Test 127Horizontal Flame Test 100 to 104Insulation Resistance Tests on Completed Cable 30 to 37Mineral Filler Content, Determination of 111 to 115Ozone Resistance Test 87 to 99Partial-Discharge Test 58 to 64Physical Tests of Insulation and Jacket Compounds 5 to 16Surface Resistivity Test
7、116 to 120Track Resistance Test 129 to 132U-Bend Discharge Test 121 to 125Water Absorption Test 65 to 71Water Absorption Test, Accelerated 72 to 86Water Absorption Test on Fibrous Coverings 105 to 1101.4 Whenever two sets of values are presented, in differentunits, the values in the first set are th
8、e standard, while those inthe parentheses are for information only.1.5 This standard does not purport to address all of thesafety problems, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the ap
9、plica-bility of regulatory limitations prior to use. For specific hazardssee Section 4.2. Referenced Documents2.1 ASTM Standards:2D149 Test Method for Dielectric Breakdown Voltage andDielectric Strength of Solid Electrical Insulating Materialsat Commercial Power FrequenciesD150 Test Methods for AC L
10、oss Characteristics and Permit-tivity (Dielectric Constant) of Solid Electrical InsulationD257 Test Methods for DC Resistance or Conductance ofInsulating MaterialsD412 Test Methods for Vulcanized Rubber and Thermoplas-tic ElastomersTensionD454 Test Method for Rubber Deterioration by Heat andAirPress
11、ureD572 Test Method for RubberDeterioration by Heat andOxygenD573 Test Method for RubberDeterioration in an AirOvenD1193 Specification for Reagent WaterD1711 Terminology Relating to Electrical InsulationD2132 Test Method for Dust-and-Fog Tracking and ErosionResistance of Electrical Insulating Materi
12、alsD3755 Test Method for Dielectric Breakdown Voltage andDielectric Strength of Solid Electrical Insulating MaterialsUnder Direct-Voltage StressD5025 Specification for Laboratory Burner Used for Small-Scale Burning Tests on Plastic MaterialsD5207 Practice for Confirmation of 20mm (50W) and125mm (500
13、W) Test Flames for Small-Scale BurningTests on Plastic MaterialsD5423 Specification for Forced-Convection Laboratory Ov-ens for Evaluation of Electrical Insulation1These test methods are under the jurisdiction of ASTM Committee D09 onElectrical and Electronic Insulating Materials and are the direct
14、responsibility ofSubcommittee D09.07 on Electrical Insulating Materials.Current edition approved Feb. 1, 2013. Published February 2013. Originallyapproved in 1937. Last previous edition approved in 2005 as D470 05. DOI:10.1520/D0470-13.2For referenced ASTM standards, visit the ASTM website, www.astm
15、.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis interna
16、tional standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Commi
17、ttee.12.2 ICEA Standard:T-24-380 Guide for Partial-Discharge Procedure33. Terminology3.1 DefinitionsFor definitions of terms used in these testmethods, refer to Terminology D1711.3.2 Definitions of Terms Specific to This Standard:3.2.1 aging (act of), nexposure of material to air or oil ata temperat
18、ure and time as specified in the relevant materialspecification for that material.3.3 Symbols:3.3.1 kcmilthousands of circular mils.4. Hazards4.1 Mercury:4.1.1 Mercury metal vapor poisoning has long been recog-nized as a hazard in industry. The exposure limits are set bygovernmental agencies and are
19、 usually based upon recommen-dations made by the American Conference of GovernmentalIndustrial Hygienists.4The concentration of mercury vaporover spills from broken thermometers, barometers, and otherinstruments using mercury can easily exceed these exposurelimits. Mercury, being a liquid with high
20、surface tension andquite heavy, will disperse into small droplets and seep intocracks and crevices in the floor. This increased area ofexposure adds significantly to the mercury vapor concentrationin air. The use of a commercially available emergency spill kitis recommended whenever a spill occurs.
21、Mercury vaporconcentration is easily monitored using commercially avail-able sniffers. Make spot checks periodically around operationswhere mercury is exposed to the atmosphere. Make thoroughchecks after spills. See 8.3.2 and 8.3.3.4.2 High Voltage:4.2.1 Lethal voltages are a potential hazard during
22、 theperformance of this test. It is essential that the test apparatus,and all associated equipment electrically connected to it, beproperly designed and installed for safe operation.4.2.2 Solidly ground all electrically conductive partswhich it is possible for a person to contact during the test.4.2
23、.3 Provide means for use at the completion of any test toground any parts which were at high voltage during the test orhave the potential for acquiring an induced charge during thetest or retaining a charge even after disconnection of thevoltage source.4.2.4 Thoroughly instruct all operators as to t
24、he correctprocedures for performing tests safely.4.2.5 When making high voltage tests, particularly in com-pressed gas or in oil, it is possible for the energy released atbreakdown to be sufficient to result in fire, explosion, orrupture of the test chamber. Design test equipment, testchambers, and
25、test specimens so as to minimize the possibilityof such occurrences and to eliminate the possibility of personalinjury. If the potential for fire exists, have fire suppressionequipment available. Design test equipment, test chambers,and test specimens so as to minimize the possibility of suchoccurre
26、nces and to eliminate the possibility of personal injury.See Sections 20, 27, 33, 42, 48, 54, 62, 68, 76, 118, 123 and130.4.3 Ozone:4.3.1 Ozone is a physiologically hazardous gas at elevatedconcentrations. The exposure limits are set by governmentalagencies and are usually based upon recommendations
27、 madeby the American Conference of Governmental Industrial Hy-gienists.4Ozone is likely to be present whenever voltages existwhich are suffcient to cause partial, or complete, discharges inair or other atmospheres that contain oxygen. Ozone has adistinctive odor which is initially discernible at low
28、 concen-trations but sustained inhalation of ozone can cause temporaryloss of sensitivity to the scent of ozone. Because of this it isimportant to measure the concentration of ozone in theatmosphere, using commercially available monitoring devices,whenever the odor of ozone is persistently present o
29、r whenozone generating conditions continue. Use appropriate means,such as exhaust vents, to reduce ozone concentrations toacceptable levels in working areas. See Section 90.PHYSICAL TESTS OF INSULATIONS ANDJACKETS5. Significance and Use5.1 Physical tests, properly interpreted, provide informationwit
30、h regard to the physical properties of the insulation orjacket. The physical test values give an approximation of howthe insulation will physically perform in its service life.Physical tests provide useful data for research anddevelopment, engineering design, quality control, and accep-tance or reje
31、ction under specifications.6. Physical Tests6.1 Physical tests shall include determination of the follow-ing:6.1.1 Tensile strength,6.1.2 Tensile stress,6.1.3 Ultimate elongation,6.1.4 Permanent set,6.1.5 Accelerated aging,6.1.6 Tear resistance,6.1.7 Effects of oil immersion, and6.1.8 Thickness of i
32、nsulations and jackets.7. Sampling7.1 Number of SamplesUnless otherwise required by thedetailed product specification, wire and cable shall be sampledfor the physical tests, other than the tests for insulation andjacket thickness, as follows:7.1.1 Sizes Less than 250 kcmil (127 mm2)One sampleshall b
33、e selected for each quantity ordered between 2000 and50 000 ft (600 and 15 000 m) of wire or cable and oneadditional sample for each additional 50 000 ft. No sampleshall be selected from lots of less than 2000 ft.7.1.2 Sizes of 250 kcmil (127 mm2) and OverOne sampleshall be selected for each quantit
34、y ordered between 1000 and3Available from the Insulated Cable Engineers Assoc., P.O. Box 440, SouthYarmouth, MA 02664.4American Conference of Governmental and Industrial Hygienists, 6500 Glen-way Ave., Building D-7, Cincinnati, OH 45211.D470 13225 000 ft (300 and 7600 m) of wire or cable and one add
35、itionalsample for each additional 25 000 ft. No sample shall beselected from lots of less than 1000 ft.7.2 Size of SamplesSamples shall be at least 6 ft (2 m) inlength when the wire size is less than 250 kcmil (127 mm2),and at least 3 ft (1 m) in length when the wire size is 250 kcmilor over.8. Test
36、 Specimens8.1 Number of SpecimensFrom each of the samples se-lected in accordance with Section 7, test specimens shall beprepared as follows:Number of TestSpecimensFor Determination of Initial Properties (Unaged):Tensile strength, tensile stress, and ultimate elongation 3Permanent set 3For Aging Tes
37、ts:Air pressure, heat, or oxygen pressure 3Air oven 3For Oil Immersion 3One specimen of each three shall be tested and the other twospecimens held in reserve, except that when only one sample isselected all three specimens shall be tested and the average ofthe results reported. For the tear test, si
38、x individual specimensas described in 8.5 shall be used.8.2 Size of SpecimensIn the case of wire and cable smallerthan AWG 6 (13.3 mm2) having an insulation thickness lessthan 0.090 in. (2.29 mm), the test specimen shall be the entiresection of the insulation. When the full cross section is used,the
39、 specimens shall not be cut longitudinally. In the case ofwire and cable of AWG 6 and larger, or in the case of wire andcable smaller than AWG 6 having an insulation thicknessgreater than 0.090 in., specimens approximately square insection with a cross section not greater than 0.025 in.2(16mm2) shal
40、l be cut from the insulation. In extreme cases, use ofa segmental specimen is permitted.8.2.1 The test specimens shall be approximately 6 in. (150mm) in length. Specimens for tests on jackets shall be takenfrom the completed wire or cable and cut parallel to the axis ofthe wire or cable. With the ex
41、ception of the tear tests, the testspecimen shall be either a segment or sector cut with a suitablesharp instrument or a shaped specimen cut out with a die andshall have a cross-sectional area not greater than 0.025 in.2(16mm2) after irregularities, corrugations, and reinforcing cords orwires have b
42、een removed by buffing.8.3 Preparation of Specimens:8.3.1 The test specimen is to have no surface incisions andbe as free as possible from other imperfections. Removesurface irregularities, such as corrugations due to stranding,etc., so that the test specimen will be smooth and of uniformthickness.8
43、.3.2 The removal of the insulation often is greatly accel-erated by using mercury. In most cases a test specimen whichis an entire section is obtained, free from surface incisions andimperfections. Warningsee 4.1. Introduce the mercury atone end of the specimen between the insulation and the tinneds
44、urface of the conductor, with the specimen inclined on asupport with the end to which the mercury is applied at the top.The separation of the insulation results from the amalgamationof the tin of the conductor with the mercury. The amalgamationis assisted by first immersing and rubbing the tinning o
45、n theexposed end of the conductor in the mercury. It is also possibleto facilitate the removal of the insulation by stretching theconductor to the breaking point in a tensile-strength machine.8.3.3 WarningMercury is a hazardous material. See 4.1.Care should be exercised to keep mercury from the hand
46、s. Theuse of rubber gloves is recommended for handling specimensas in 8.3.2.8.4 Specimens of Thin-Jacketed InsulationIn the case ofwires or cables having a thin jacket crosslinked directly to theinsulation, it is usually necessary to prepare die-cut specimensof the jacket and insulation. Make an eff
47、ort to separate thejacket from the insulation by slitting the covering through tothe conductor and pulling the jacket and insulation apart bypliers. (Immersing the sample in hot water for a few minutesjust prior to pulling off the jacket often facilitates this proce-dure.) If the jacket cannot be re
48、moved, prepare specimens bybuffing. Equip the buffing apparatus with a cylindrical tablearranged so that it can be advanced very gradually. Remove theconductor from two short lengths of wire by slitting thecovering. Stretch one length of covering into the clamps of thebuffing apparatus so that it li
49、es flat, with the jacket toward thewheel. The jacket is buffed off, with due care not to buff anyfurther than necessary, or overheat the material. Repeat theprocess with the other length of covering, except that theinsulation is buffed off. Die-cut specimens shall be preparedfrom the buffed pieces after they have been allowed to recoverfor at least 30 min. Jackets with a thickness of less than 0.030in. (0.76 mm) shall not be tested.8.5 Specimen for the Tear TestCut the specimen with asharp knife or die. After irregularities, corrugations, andreinforcing cords or
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