1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS 7870-3.21:2011Incorporating Corrigendum No. 1LV and MV polymericinsulated cables for use bydistribution and generationutilitiesPart 3: Specification for distributioncables of
2、rated voltage 0.6/1 kVSection 3.21: XLPE insulated splitconcentric cables with copper oraluminium conductors(Implementation of HD 603)Publishing and copyright informationThe BSI copyright notice displayed in this document indicates when the documentwas last issued. The British Standards Institution
3、2012Published by BSI Standards Limited 2012ISBN 978 0 580 78836 9ICS 29.060.20The following BSI references relate to the work on this standard:Committee reference GEL/20/16Draft for comment 11/30215743 DCPublication historyFirst published August 2001Second (present) edition, December 2011Amendments
4、issued since publicationDate Text affectedAugust 2012 See forewordBS 7870-3.21:2011 BRITISH STANDARDContentsForeword ii1 Scope 12 Normative references 13 Voltage designation 14 Phase conductors 25 Insulation 26 Assembly of cores 27 Bedding for 3-phase cables 28 Concentric layer 29 Binder tapes 310 O
5、versheath 311 Marking 412 End sealing 513 Dimensions 514 Tests 915 Routine tests 1016 Sample tests 1017 Type tests 11AnnexesAnnex A (informative) Guide to selection and use of cables 13Bibliography 14List of tablesTable 1 Cables with single phase copper conductor and split concentric copperneutral/e
6、arth conductors 6Table 2 Cables with single phase aluminium conductor and split concentriccopper neutral/earth conductors 7Table 3 Cables with 3-phase copper conductors and split concentric copperneutral/earth conductors 7Table 4 Cables with 3-phase aluminium conductors and split concentric copperne
7、utral/earth conductors 8Table 5 Schedule of tests 9Table 6 Requirements for compatibility of insulation and oversheath 12Table A.1 Guide to use 13Summary of pagesThis document comprises a front cover, an inside front cover, pages i to iv,pages 1 to 14, an inside back cover and a back cover.BRITISH S
8、TANDARD BS 7870-3.21:2011 The British Standards Institution 2012 iForewordPublishing informationThis section of BS 7870 is published by BSI Standards Limited, under licence fromThe British Standards Institution, and came into effect on 31 December 2011. Itwas prepared by Subcommittee GEL/20/16, Medi
9、um/High voltage cables, underthe authority of Technical Committee GEL/20, Electric cables. A list oforganizations represented on these committees can be obtained on request totheir secretary.SupersessionThis section of BS 7870 supersedes BS 7870-3.21:2001, which is withdrawn.Relationship with other
10、publicationsBS 7870 implements the nationally applicable parts of Harmonization DocumentsHD 603, 605, 620, 626 and 627 published by the European Committee forElectrotechnical Standardization (CENELEC) in accordance with the decision ofthe CENELEC Technical Board.BS 7870 applies to cables for fixed i
11、nstallations having a rated voltage U0/U upto and including 19/33 kV, and is published as a series of separate parts andsections, as listed in the table in the foreword of BS 7870-1.BS 7870-3.21 specifies a range of XLPE insulated split concentric service cables; itimplements Part 5S of HD 603 S1 A2
12、, and is to be read in conjunction withBS 7870-1 and BS 7870-2.BS 7870-3.20 specifies a range of split concentric service cables with PVCinsulation.BS 7870-3.22 is a new section that specifies a similar range of split concentricservice cables which have XLPE insulation and low emission of smoke andc
13、orrosive gases when affected by fire.Information about this documentThis is a full revision of the standard, and brings the standard up to date inaccordance with current practice in the industry.The start and finish of text introduced or altered by Corrigendum No. 1 isindicated in the text by tagsan
14、d.A general guide to use for the types of cable specified in BS 7870 is given inBS 7870-1 and specific details for the types of cable specified in this section ofBS 7870 are given in Annex A.Hazard warningsWARNING. This British Standard calls for the use of substances and/orprocedures that can be in
15、jurious to health if adequate precautions are nottaken. It refers only to technical suitability and does not absolve the userfrom legal obligations relating to health and safety at any stage.Use of this documentIt has been assumed in the preparation of this British Standard that theexecution of its
16、provisions will be entrusted to appropriately qualified andexperienced people, for whose use it has been produced.BRITISH STANDARDBS 7870-3.21:2011ii The British Standards Institution 2012Presentational conventionsThe provisions of this standard are presented in roman (i.e. upright) type. Itsrequire
17、ments are expressed in sentences in which the principal auxiliary verb is“shall”.Commentary, explanation and general informative material is presented insmaller italic type, and does not constitute a normative element.Contractual and legal considerationsThis publication does not purport to include a
18、ll the necessary provisions of acontract. Users are responsible for its correct application.Compliance with a British Standard cannot confer immunity from legalobligations.BRITISH STANDARD BS 7870-3.21:2011 The British Standards Institution 2012 iiiBRITISH STANDARDBS 7870-3.21:2011This page delibera
19、tely left blankiv The British Standards Institution 20121 ScopeThis section of BS 7870 specifies requirements for the construction, dimensionsand mechanical and electrical properties of split concentric service cables havinga rated voltage of 0.6/1(1.2) kV.It specifies requirements for the following
20、 types of cable:a) single phase or 3-phase;b) stranded copper or solid aluminium conductors;c) XLPE insulation and PVC oversheath.This section of BS 7870 is applicable to cables that are designed for a maximumcontinuous conductor operating temperature of 90 C and for a maximum shortcircuit conductor
21、 temperature of 250 C.2 Normative referencesThe following referenced documents are indispensable for the application ofthis document. For dated references, only the edition cited applies. For undatedreferences, the latest edition of the referenced document (including anyamendments) applies.BS 3988:1
22、970+A3:1989, Specification for wrought aluminium for electricalpurposes Solid conductors for insulated cablesBS 7870-1, LV and MV polymeric insulated cables for use by distribution andgeneration utilities Part 1: GeneralBS 7870-2, LV and MV polymeric insulated cables for use by distribution andgener
23、ation utilities Part 2: Methods of testBS EN 60228, Specification for conductors in insulated cables and cordsBS EN 60332-1-2:2004, Tests on electric and optical fibre cables under fireconditions Part 1-2: Test for vertical flame propagation for a single insulatedwire or cable Procedure for 1 kW pre
24、-mixed flameBS EN 60811-1-1, Insulating and sheathing materials of electric and opticalcables Common test methods Part 1-1: General application Measurement ofthickness and overall dimensions Tests for determining the mechanicalpropertiesBS EN 60811-1-2, Common test methods for insulating and sheathi
25、ng materialsof electric and optical cables Common test methods Part 1-2: Generalapplication Thermal ageing methodsBS EN 60811-1-3, Insulating and sheathing materials of electric and opticalcables Common test methods Part 1-3: General application Methods fordetermining the density Water absorption te
26、sts Shrinkage test3 Voltage designationCables shall be designated by the voltages U0, U and Um, expressed in the formU0/U (Um).The voltage designation of cables in this standard shall be 0.6/1(1.2) kV.The rated voltage of the cable shall be at least equal to the nominal voltage ofthe system for whic
27、h it is intended.BRITISH STANDARD BS 7870-3.21:2011 The British Standards Institution 2012 14 Phase conductorsThe phase conductors shall be either stranded (class 2) plain annealed copper orsolid (class 1) aluminium conductors in accordance with BS EN 60228. Class 1conductors shall also conform to t
28、he dimensional requirements specified inBS 3988:1970+A3, 2.4.1.Conformity shall be checked by visual examination and, in the case of class 1conductors, by measurement, as specified in 16.2.The d.c. resistance shall conform to the relevant value given in Table 1 toTable 4, as applicable.Conformity sh
29、all be checked by the test method specified in 15.2.5 InsulationThe insulation shall be XLPE compound type DIX 3, conforming to therequirements given in BS 7870-1, Annex B.The insulation shall be applied by extrusion and shall form a compact andhomogeneous layer.The thickness of the insulation shall
30、 be in accordance with the relevant valuesspecified in Table 1 to Table 4, as applicable.Conformity shall be checked by the test methods specified in 16.4.The cores of all cables shall be identified by colours, as follows:a) Single-core: brown;b) 3-core: brown, black and grey.6 Assembly of coresThe
31、cores of 3-phase cables shall be laid up with a right-hand direction of layand a minimum lay length of 550 mm.NOTE Where necessary, fillers of suitable synthetic material may be used.7 Bedding for 3-phase cablesA PVC or synthetic tape bedding, having an approximate total thickness of0.5 mm, shall be
32、 applied over the laid-up cores of 3-phase cables.NOTE At the discretion of the manufacturer a polyester separation tape may beapplied between the laid-up cores and the PVC tape as part of the bedding.8 Concentric layer8.1 Neutral conductorThe neutral conductor shall be manufactured from plain annea
33、led copper wires.The d.c. resistance shall conform to the relevant value given in Table 1 toTable 4, as applicable.Conformity shall be checked by the test method specified in 15.2.To distinguish the neutral conductor from the earth continuity conductor, eachwire shall be covered by extrusion with a
34、blue polymeric compound, conformingto the requirements of 17.3, to a diameter approximately the same as that ofthe individual wires in the earth continuity conductor.BRITISH STANDARDBS 7870-3.21:20112 The British Standards Institution 2012The lay length shall not exceed the relevant value given in T
35、able 1 to Table 4, asapplicable, by more than 50%.Conformity shall be checked by visual examination and measurement asspecified in 16.3.NOTE The covering should not be regarded as insulation.8.2 Earth continuity conductorThe earth continuity conductor shall be manufactured from bare plain annealedco
36、pper wires.Conformity shall be checked by visual examination as specified in 16.3.The d.c. resistance shall conform to the relevant value given in Table 1 toTable 4, as applicable.Conformity shall be checked by the test method specified in 15.2.8.3 Non-hygroscopic string separatorsThe non-hygroscopi
37、c string separators shall be approximately the same diameteras the individual bare wires forming the earth continuity conductor.Conformity shall be checked by visual examination as specified in 16.3.8.4 Application of concentric layerThe concentric layer shall be applied with a right-hand direction
38、of lay. Thewires forming the neutral conductor and earth continuity conductor shall beapplied in individual groups over the insulation with non-hygroscopic stringseparators.Either one or two non-hygroscopic string separator(s) shall be located on eitherside of the group of bare copper wires to separ
39、ate it from the group of coveredwires.The length of lay and number of strings shall be such that coverage ofapproximately 90% is achieved.Conformity shall be checked by visual examination as specified in 16.3.NOTE Examples of concentric conductor construction are given in Table 1 toTable 4.9 Binder
40、tapesOne or more overlapped synthetic binder tape(s) shall be applied immediatelyover the concentric layer.10 OversheathThe oversheath shall be an extruded layer of PVC compound type DMV 23,conforming to the requirements given in BS 7870-1, Annex B.NOTE Oversheaths are normally black but colours oth
41、er than black may beprovided by agreement between the manufacturer and the purchaser, subject totheir suitability for the particular conditions under which the cables are to be used.The thickness of the oversheath shall conform to the relevant values specified inTable 1 to Table 4, as applicable.Con
42、formity shall be checked by the test methods specified in 16.5.BRITISH STANDARD BS 7870-3.21:2011 The British Standards Institution 2012 311 Marking11.1 External markingThe external surface of the cable shall be legibly marked with the followingelements:Element Example of markinga) Cable manufacture
43、r Manufacturers name and their uniquefactory identifierNOTE 1 A simplified version of the manufacturers name, or trading name of themanufacturer, may be used in place of the full name.NOTE 2 Any suitable method may be used to unambiguously identify themanufacturers factory.NOTE 3 The manufacturers o
44、wn trademark or equivalent may be added but thiscannot be used instead of the manufacturers name and identifier.b) Electric cable ELECTRIC CABLEc) Voltage designation 600/1 000 Vd) British Standard number BS 7870-3.211)e) Number of cores, type and nominalarea of phase conductors, e.g.:3-core cable w
45、ith 25 mm2aluminium phase conductors325ALsingle-core cable with a 25 mm2copper phase conductor125f) Year of manufacture YYYYNOTE 4 The year of manufacture may take the form of the actual year (e.g. 2011)or a coded year identifier assigned by the manufacturer.The marking of elements a) to f) shall be
46、 by embossing or by indenting on theoversheath.For cables with overall diameters greater than 15 mm, as given in Table 1 toTable 4, elements b), c) and d) shall appear, in any sequence that is deemedneither to confuse nor to conflict, on two or more primary lines along the axisof the cable, approxim
47、ately equally spaced around the circumference of thecable. Elements a), e) and f) shall appear, together or separately, in anysequence that is deemed neither to confuse nor to conflict, either on one of theprimary lines, or on a secondary line or lines.For cables with overall diameters of 15 mm or l
48、ess, as given in Table 1 toTable 4, the elements shall be arranged as for cables of greater than 15 mmdiameter, except that the marking for elements b), c) and d) shall appear on oneor more primary lines.The letters and figures shall consist of upright block characters. The charactersshall have a mi
49、nimum height of 3 mm.1)Marking BS 7870-3.21 on or in relation to a product represents a manufacturersdeclaration of conformity, i.e. a claim by or on behalf of the manufacturer that theproduct meets the requirements of the standard. The accuracy of the claim is solelythe claimants responsibility. Such a declaration is not to be confused with third-partycertification of conformity.BRITISH STANDARDBS 7870-3.21:20114 The British Standards Institution 2012The distance between the end of one element of markin
