ASTM_D_2768_-_95_2001.pdf

Designation:D 2768 95(Reapproved 2001)An American National StandardStandard Specification forGeneral-Purpose Ethylene-Propylene Rubber Jacket forWire and Cable1This standard is issued under the fixed designation D 2768;the number immediately following the designation indicates the year oforiginal adoption 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.Scope1.1 This specification covers a weather and ozone-resistingcrosslinked compound for use as the outer covering or jacketon insulated wires and cables.The polymer component of thismaterial consists substantially of ethylenepropylene copolymer(EPM)or ethylene-propylene terpolymer(EPDM).1.2 The values stated in inch-pound units are the standard,except in cases where SI units are more appropriate.The valuesin parentheses are for information only.2.Referenced Documents2.1 ASTM Standards:D 257 Test Methods for DC Resistance or Conductance ofInsulating Materials2D 470 Test Methods for Crosslinked Insulations and Jacketsfor Wire and Cable2D 1499 Practice for Filtered Open-Flame Carbon-Arc Ex-posures of Plastics3G 23 Practice for Operating Light-Exposure Apparatus(Carbon-Arc Type)With and Without Water for Exposureof Nonmetallic Materials43.Electrical Requirements3.1 When used on single conductor nonshielded cables rated2001 through 5000 V phase to phase,the jacket shall meet thefollowing requirements of Test Methods D 470:3.1.1 Surface ResistivityThe jacket shall have a surfaceresistivity equal to or greater than 200 000 MV.3.1.2 U-Bend DischargeThere shall be no cable failurenor cracks in the jacket when a sample of completed cable issubjected to the U-bend discharge test at 150 V/mil(6 kV/mm)for at least 6 h.4.Test Applicable for Sunlight and Weather ResistantMaterials4.1 The jacket shall retain a minimum of 80%of its unagedtensile strength and elongation after 720 h of exposure in a dualcarbon-arc apparatus.Prepare the specimens in accordancewith Test Methods D 470 for physical tests of insulations andjackets.Perform the test in accordance with Practice D 1499using Method 1 of Practice G 23.5.Physical Requirements5.1 The crosslinked jacket shall conform to the physicalproperties specified in Table 1.6.Sampling6.1 Sample the jacket in accordance with Test MethodsD 470.7.Test Methods7.1 Unless otherwise instructed,test the jacket in accor-dance with Test Methods D 470.8.Keywords8.1 ethylene-propylene rubber;sunlight resistant;surfaceresistivity;U-bend discharge;weather resistant1This specification is under the jurisdiction of ASTM Committee D09 onElectrical and Electronic Insulating Materials and is the direct responsibility ofSubcommittee D09.18 on Solid Insulations,Non-Metallic Shieldings and Coveringsfor Electrical and Telecommunication Wires and Cables.Current edition approved Feb.15,1995.Published April 1995.Originallypublished as D 276868.Last previous edition D 276889.2Annual Book of ASTM Standards,Vol 10.01.3Annual Book of ASTM Standards,Vol 08.01.4Discontinued;see 1996 Annual Book of ASTM Standards,Vol 14.02.1Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959,United States.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item 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 committee 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 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 Drive,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).TABLE 1 Physical Properties for General-Purpose EPM or EPDMJacketAUnexposed(Unaged)Requirements:Tensile strength,min,psi1500(MPa)(10.3)Elongation at rupture,min,%200Exposed(Aged)Requirements:After air oven test at 121 6 1C for 168 h:Tensile strength,min,psi1200(MPa)(8.3)Elongation at rupture,min,%175AThe values specified are applicable only to jackets having a nominal thicknessof.030 in.(0.76 mm)or more.D 2768 95