1、Designation: D2656 13Standard Specification forCrosslinked Polyethylene Insulation for Wire andCable Rated 2001 to 35 000 V1This standard is issued under the fixed designation D2656; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision,
2、the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This specification covers a crosslinked polyethyleneinsulation for electrical wires and cables for conduc
3、tor 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, 130 C for emer-gency overload
4、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 ratings of 2001 to 25 000V at the 13
5、3 % insulation level as listed in Table 1C of TestMethods D470.1.3 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 the insulation cannot be tested unl
6、essit 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 differentunits, the values in the first s
7、et are the standard, while those inparentheses are for information only.2. Referenced Documents2.1 ASTM Standards:2D470 Test Methods for Crosslinked Insulations and Jacketsfor Wire and CableD1248 Specification for Polyethylene Plastics ExtrusionMaterials for Wire and CableD1711 Terminology Relating
8、to Electrical InsulationD2765 Test Methods for Determination of Gel Content andSwell Ratio of Crosslinked Ethylene Plastics2.2 ICEA Standard:ICEA T-28-562 Test Method for Measurement of Hot Creepof Polymeric Insulation33. Terminology3.1 Definitions:3.1.1 For definitions of terms used in this specifi
9、cation referto Terminology D1711.4. Physical Properties4.1 The requirements for the insulation are listed in Table 1.5. 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.
10、 The sequence for othertesting is not specified.5.2 Partial Discharge (Corona) Extinction VoltageEachlength of completed power cable with shielded conductorsshall comply with the minimum level specified in Table 2.Conduct the tests in accordance with Test Methods D470.5.3 AC Voltage TestSubject the
11、wires and cables to an actest voltage for a period of 5 min. Unless otherwise specified,omit this test if the dc voltage 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 phas
12、e. Conduct the test in accordancewith Test Methods D470.5.4 Insulation ResistanceThe insulated conductor shallhave an 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 f
13、rom 60 F, apply a correction factor. Table 2 of1This specification is under the jurisdiction of ASTM Committee D09 onElectrical and Electronic Insulating Materials and is the direct responsibility ofSubcommittee D09.07 on Electrical Insulating Materials.Current edition approved Nov. 1, 2013. Publish
14、ed November 2013. Originallyapproved in 1967. Last previous edition approved in 2006 as D2656 06. DOI:10.1520/D2656-13.2For 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
15、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:/.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C7
16、00, West Conshohocken, PA 19428-2959. United States1Test Methods D470 contains the correction factors. Eachinsulation manufacturer can furnish the 1 F coefficient for theinsulation material by using the procedure given in TestMethods D470. Multiply the measured value by the correctionfactor to obtai
17、n the insulation-resistance value corrected to 60F.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 ins
18、ulation resistance shall be at least 60 % of thatrequired 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.
19、 Use a dcvoltage three times the ac voltage based on the specifiednominal thickness of insulation for the rated circuit voltage,phase to phase. Conduct the tests in accordance with TestMethods D470.5.5.1 Upon completion of the insulation resistance test, eachnonshielded insulated conductor rated up
20、to 5000 V shallwithstand for 5 min a dc test voltage 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 o
21、f Table 3 when tested inaccordance with theAccelerated WaterAbsorption Tests in TestMethods D470. 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 permittivityan
22、d dissipation factor on suitable 60-Hz equipment 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
23、circuit voltage, phase to phase. The insulation shall 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 th
24、e test period no cable dielectric failures or cracksin the cable surface are permitted. Conduct the test in accor-dance with Test Methods D470.5.9 Surface ResistivityPerform this test only on single-conductor nonshielded cables rated 2001 through 5000 V. Thesurface resistivity shall exceed 200 000 M
25、. Conduct the testin accordance with Test Methods D470.6. Heat Distortion6.1 The requirements for heat distortion are given in Table1 of this Specification. The test is conducted in accordance withTest Methods D470.7. Percent Hot Creep and Percent Hot Set7.1 Determine the percent hot creep for 15 mi
26、n at 150 C(302 F) as follows: Meet the filled 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 accord
27、ance with Practice ICEAT-28-562.7.3 In case of dispute, the solvent extraction test in TestMethods D2765 is to be the referee method. The extractables,after a drying time of 20 h, shall be no more than 30 percent.TABLE 1 Physical Properties for CrosslinkedPolyethylene InsulationUnaged Requirements:T
28、ensile strength, min, psi (MPa) 1800 (12.4)Elongation at rupture, min % 250Aged Requirements:After Air Oven Test at 1211Cfor168h:Tensile strength, min, % of unaged value 75Elongation at rupture, min, % of unaged value 75Heat Distortion:At 121 1 C, max, % of unaged value:4/0 Awg (107 mm2) and smaller
29、 (insulation on cable) 30Larger than 4/0 Awg (107 mm2) (buffed sample ofinsulation)15Percent Hot Creep, maxFilledA100UnfilledB175Percent Hot Set, maxFilledA5UnfilledB10AFilled indicates a crosslinked polyethylene insulation that contains 10 % orgreater carbon black and/or mineral fillers.BUnfilled i
30、ndicates a crosslinked polyethylene insulation that contains less than10 % carbon black and/or mineral fillers.TABLE 2 Partial Discharge (Corona) Extinction VoltageRequirementsRated Circuit VoltagePhase to Phase, VMinimum Level, kVGroundedNeutralUngroundedNeutralShielded2 001 to 5 000 4 5A5 001 to 8
31、 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.TABLE 3 Accelerated Water Absorption TestRequirementsElectrical Method:Permittivity after one day, max 3.5Increase in capacitance, max, %:Fro
32、m 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 0.5D2656 1328. Test Applicable for Sunlight and Weather ResistantMaterials8.1 For insulations requiring sunlight- and weather-resistance testin
33、g, test in accordance with “Weatherability forColored Materials (including white and black)” in Specifica-tion D1248. Prepare the specimens in accordance with TestMethods D470 for physical tests of insulations and jackets.9. Sampling9.1 Unless otherwise specified, sample the insulation inaccordance
34、with Test Methods D470.10. Test Methods10.1 Unless otherwise specified, test the insulation in accor-dance with Test Methods D470.11. Keywords11.1 ac voltage; crosslinked polyethylene; dc voltage; heatdistortion; hot creep; hot set; insulation resistance; waterabsorption; weather resistantSUMMARY OF
35、 CHANGESCommittee D09 has identified the location of selected changes to this specification since the last issue,D2656 06, that may impact the use of this specification. (Approved Nov. 1, 2013)(1) Revised Section 3.ASTM International takes no position respecting the validity of any patent rights ass
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