1、Designation: D 2656 06An American National StandardStandard Specification forCrosslinked Polyethylene Insulation for Wire andCable Rated 2001 to 35 000 V1This standard is issued under the fixed designation D 2656; the number immediately following the designation indicates the year oforiginal adoptio
2、n or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This specification covers a crosslinked polyethyleneinsulation for electr
3、ical wires and cables for conductor sizes 8AWG (8.37 mm2) and larger. The base polymer of thisinsulation consists substantially of polyethylene.1.2 This type of insulation is suitable for use on powercables in wet and dry locations at conductor temperatures notexceeding 90 C for continuous operation
4、, 130 C for emer-gency overload conditions, and 250 C for short-circuit con-ditions. It is considered suitable for all sizes and voltageclassifications of single- and multiple-conductor power cablesat voltage ratings of 2001 to 35 000 V phase-to-phase at the100 % insulation level and at voltage rati
5、ngs of 2001 to 25 000V at the 133 % insulation level as listed in Table 1C of TestMethods D 470.1.3 Materials covered by this specification are not sunlight-and weather-resistant unless they are carbon black pigmentedor contain an additive system designed for this protection.1.4 In many instances th
6、e insulation cannot be tested unlessit has been formed around a conductor. Therefore, tests aredone on insulated wire in this standard solely to determine therelevant property of the insulation and not to test the conductoror completed cable.1.5 Whenever two sets of values are presented, in differen
7、tunits, the values in the first set are the standard, while those inparentheses are for information only.2. Referenced Documents2.1 ASTM Standards:2D 470 Test Methods for Crosslinked Insulations and Jacketsfor Wire and CableD 1248 Specification for Polyethylene Plastics ExtrusionMaterials for Wire a
8、nd CableD 1711 Terminology Relating to Electrical InsulationD 2765 Test Methods for Determination of Gel Content andSwell Ratio of Crosslinked Ethylene Plastics2.2 ICEA Standard:ICEAT-28-562 Test Method for Measurement of Hot Creepof Polymeric Insulation33. Terminology3.1 Definitions:3.1.1 For defin
9、itions of terms used in this specification referto Terminology D 1711.3.2 Definitions of Terms Specific to This Standard:3.2.1 aging (act of), nexposure of materials to air at 121C for 168 h.4. Physical Properties4.1 The requirements for the insulation are listed in Table 1.5. Electrical Requirement
10、s Electrical Requirements5.1 Order of TestingPerform the partial-discharge, acvoltage, insulation resistance, and dc voltage tests in that orderwhen any of these tests are specified. The sequence for othertesting is not specified.5.2 Partial Discharge (Corona) Extinction VoltageEachlength of complet
11、ed power cable with shielded conductorsshall comply with the minimum level specified in Table 2.Conduct the tests in accordance with Test Methods D 470.5.3 AC Voltage TestSubject the wires and cables to an actest voltage for a period of 5 min. Unless otherwise specified,omit this test if the dc volt
12、age test described in 5.5 is to beperformed. Test at a voltage of 125 V/mil (5 kV/mm) based onthe specified nominal thickness of insulation for the ratedcircuit voltage, phase to phase. Conduct the test in accordancewith Test Methods D 470.5.4 Insulation ResistanceThe insulated conductor shallhave a
13、n insulation resistance equal to or greater than thatcorresponding to a constant of 20 000 at 60 F (15.6 C).When the temperature of the water in which the insulation istested differs from 60 F, apply a correction factor. Table 2 ofTest Methods D 470 contains the correction factors. Each1This specifi
14、cation is under the jurisdiction of ASTM Committee D09 onElectrical and Electronic Insulating Materials and is the direct responsibility ofSubcommittee D 09.18 on Solid Insulations, Non-Metallic Shieldings, and Cover-ings for Electrical and Telecommunications Wires and Cables.Current edition approve
15、d Oct. 1, 2006. Published October 2006. Originallyapproved in 1967. Last previous edition approved in 2000 as D 2656 00.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer
16、 to the standards Document Summary page onthe ASTM website.3Available from The Insulated Cable Engineers Association, Inc. (ICEA), P.O.Box 1568, Carrollton, GA 30112, http:/.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box
17、 C700, West Conshohocken, PA 19428-2959, United States.insulation manufacturer can furnish the 1 F coefficient for theinsulation material by using the procedure given in TestMethods D 470. Multiply the measured value by the correctionfactor to obtain the insulation-resistance value corrected to 60F.
18、5.4.1 Where a nonconducting separator is applied betweenthe conductor and insulation or where an insulated conductor iscovered with a nonmetallic jacket so that the insulationresistance can be measured only on the completed assembly,the required insulation resistance shall be at least 60 % of thatre
19、quired for the primary insulation based on the nominalthickness of that insulation.5.5 DC Voltage TestAfter the insulation resistance test hasbeen completed, subject wires and cables rated 5001 V andabove to a dc voltage test for a period of 15 min. Use a dcvoltage three times the ac voltage based o
20、n the specifiednominal thickness of insulation for the rated circuit voltage,phase to phase. Conduct the tests in accordance with TestMethods D 470.5.5.1 Upon completion of the insulation resistance test, eachnonshielded insulated conductor rated up to 5000 V shallwithstand for 5 min a dc test volta
21、ge that is three times the actest voltage specified in 5.3. Unless otherwise specified, omitthis test if the ac voltage test described in 5.3 has beenperformed.5.6 Accelerated Water Absorption RequirementsThe insu-lation shall meet the requirements of Table 3 when tested inaccordance with theAcceler
22、ated WaterAbsorption Tests in TestMethods D 470. Conduct the Electrical Method Test at 60 Hzwith the water temperature at 75 6 1 C.5.7 Permittivity and Dissipation FactorThis test appliesto insulation rated 5001 V and above. Measure the permittivityand dissipation factor on suitable 60-Hz equipment
23、after thetest specimen has been immersed in water at room temperaturefor at least 24 h. Make the measurements at a voltagecorresponding to an average stress of 40 V/mil (1.6 kV/mm),based upon the specified nominal thickness of insulation for therated circuit voltage, phase to phase. The insulation s
24、hall meetthe following requirements:Permittivity at room temperature, max 3.5Dissipation factor at room temperature, max, 0.0205.8 U-Bend DischargePerform this test only on single-conductor nonshielded cables rated 2001 through 5000 V. Atthe end of the test period no cable dielectric failures or cra
25、cksin the cable surface are permitted. Conduct the test in accor-dance with Test Methods D 470.5.9 Surface ResistivityPerform this test only on single-conductor nonshielded cables rated 2001 through 5000 V. Thesurface resistivity shall exceed 200 000 MV. Conduct the testin accordance with Test Metho
26、ds D 470.6. Heat Distortion6.1 The requirements for heat distortion are given in Table1 of this Specification. The test is conducted in accordance withTest Methods D 470.7. Percent Hot Creep and Percent Hot Set7.1 Determine the percent hot creep for 15 min at 150 C(302 F) as follows: Meet the filled
27、 or unfilled values specifiedin Table 1. Conduct this test in accordance with Practice ICEAT-28-562.7.2 Determine the percent hot set for 5 min at 150 C (302F) as follows: Meet the filled or unfilled values specified inTable 1. Conduct this test in accordance with Practice ICEAT-28-562.7.3 In case o
28、f dispute, the solvent extraction test in TestMethods D 2765 is to be the referee method. The extractables,after a drying time of 20 h, shall be no more than 30 percent.8. Test Applicable for Sunlight and Weather ResistantMaterials8.1 For insulations requiring sunlight- and weather-resistance testin
29、g, test in accordance with “Weatherability forTABLE 1 Physical Properties for CrosslinkedPolyethylene InsulationUnaged Requirements:Tensile strength, min, psi (MPa) 1800 (12.4)Elongation at rupture, min % 250Aged Requirements:After Air Oven Test at 121 6 1 C for 168 h:Tensile strength, min, % of una
30、ged value 75Elongation at rupture, min, % of unaged value 75Heat Distortion:At 1216 1 C, max, % of unaged value:4/0 Awg (107 mm2) and smaller (insulation on cable) 30Larger than 4/0 Awg (107 mm2) (buffed sample ofinsulation)15Percent Hot Creep, maxFilledA100UnfilledB175Percent Hot Set, maxFilledA5Un
31、filledB10AFilled indicates a crosslinked polyethylene insulation that contains 10 % orgreater carbon black and/or mineral fillers.BUnfilled indicates a crosslinked polyethylene insulation that contains less than10 % carbon black and/or mineral fillers.TABLE 2 Partial Discharge (Corona) Extinction Vo
32、ltageRequirementsRated Circuit VoltagePhase to Phase, VMinimum Level, kVGroundedNeutralUngroundedNeutralShielded2 001 to 5 000 4 5A5 001 to 8 000 6 88 001 to 15 000 11 1515 001 to 25 000 19 2625 001 to 28 000 2128 001 to 35 000 26AUnless otherwise indicated the cable shall be rated grounded neutral.
33、TABLE 3 Accelerated Water Absorption TestRequirementsElectrical Method:Permittivity after one day, max 3.5Increase in capacitance, max, %:From 1 to 14 days 3.0From 7 to 14 days 1.5Stability factor after 14 days, max 1.0Alternative to stability factor:Stability factor difference, 1 to 14 days, max 0.
34、5D2656062Colored Materials (including white and black)” in Specifica-tion D 1248. Prepare the specimens in accordance with TestMethods D 470 for physical tests of insulations and jackets.9. Sampling9.1 Unless otherwise specified, sample the insulation inaccordance with Test Methods D 470.10. Test Me
35、thods10.1 Unless otherwise specified, test the insulation in accor-dance with Test Methods D 470.11. Keywords11.1 ac voltage; crosslinked polyethylene; dc voltage; heatdistortion; hot creep; hot set; insulation resistance; waterabsorption; weather resistantSUMMARY OF CHANGESCommittee D09 has identif
36、ied the location of selected changes to this specification since the last issue,D 2656 00, that may impact the use of this specification. (Approved October 1, 2006)(1) Revised Table 1.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any it
37、em mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical com
38、mittee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a
39、meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Driv
40、e, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).D2656063
