1、BRITISH STANDARD BS 7870-3.20: 2001 Incorporating Amendment No. 1 LV and MV polymeric insulated cables for use by distribution and generation utilities Part 3: Specification for distribution cables of rated voltage 0.6/1 kV Section 3.20: PVC insulated split concentric cables with copper or aluminium
2、 conductors (Implementation of HD 603) ICS 29.060.20 BS 7870-3:20:2001 This British Standard, having been prepared under the direction of the Electrotechnical Sector Committee, was published under the authority of the Standards Committee and comes into effect on 15 September 2001 BSI 5 February 2004
3、 The following BSI references relate to the work on this British Standard: Committee reference GEL/20/2 Draft for comment 99/244661 DC ISBN 0 580 37562 5 Committees responsible for this British Standard The preparation of this British Standard was entrusted by Technical Committee GEL/20, Electric ca
4、bles, to Subcommittee GEL/20/2, Mains cables, 1kV and above, upon which the following bodies were represented: Association of Consulting Engineers British Approvals Service for Cables British Cables Association British Plastics Federation Electricity Association ERA Technology Ltd. London Undergroun
5、d Ltd. UK Steel Association Amendments issued since publication Amd. No. Date Comments 14407 5 February 2004 See foreword.BS 7870-3:20:2001 BSI 5 February 2004 i Contents Committees responsible Inside front cover Foreword ii 1S c o p e 1 2 Normative references 1 3 Voltage designation 1 4 Phase condu
6、ctor 1 5 Insulation 2 6 Concentric layer 2 7B i n d e r s 2 8O v e r s h e a t h 2 9M a r k i n g 3 10 End sealing 4 11 Dimensions 4 12 Tests 6 13 Routine tests 6 14 Sample tests 7 15 Type tests 8 Bibliography 9 Table 1 Single phase copper conductor with split concentric copper neutral/earth conduct
7、ors 4 Table 2 Single phase aluminium conductor with split concentric copper neutral/earth conductors 5 Table 3 Schedule of tests 6 Table 4 Insulation resistance 7 Table 5 Requirements for compatibility of insulation and oversheath 8BS 7870-3:20:2001 ii BSI 5 February 2004 Foreword This section of BS
8、 7870 has been prepared by Subcommittee GEL/20/2. It supersedes BS 7870-3.2:1996, which is withdrawn. The start and finish of text introduced or altered by amendment is indicated in the text by tags !“. Tags indicating changes to text carry the number of the amendment. For example, text altered by a
9、mendment No. 1 is indicated by !“. BS 7870 implements the nationally applicable parts of Harmonization Documents HD 603, 604, 605, 620, 622, 626 and 627 published by the European Committee for Electrotechnical Standardization (CENELEC) in accordance with the decision of the CENELEC Technical Board.
10、BS 7870 applies to cables for fixed installations having a rated voltage U 0 /U up to and including 19/33 kV, and is published as a series of separate parts and sections, as listed in the table in the foreword of BS 7870-1. BS 7870-3.20 specifies a range of PVC insulated split concentric service cab
11、les, implements Part 3N of HD 603 S1 A2, and is to be read in conjunction with BS 7870-1 and BS 7870-2. BS 7870-3.20 is a full technical revision of BS 7870-3.2. BS 7870-3.21 specifies a range of split concentric service cables that have XLPE insulation. A “Guide to use” for these types of cable is
12、under consideration. Amendment No. 1:2004 implements the changes to the identification of cores by colours, in accordance with HD 308 S2. The principal identification colours are now: Single phase Green-and-yellow (Earth); blue (Neutral); brown (Live). Three phase Green-and-yellow (Earth); blue (Neu
13、tral); brown, black, grey (Live). Users should ensure that any interconnection between cables with these new colours and those with the pre-existing ones is carried out safely. BS 7671, as amended in parallel with this standard, gives some guidance in this respect, but does not cover all installatio
14、n conditions or cable uses. The provisions introduced by amendment No. 1:2004 are effective from 1 st April 2004. The original version of this standard remains current until 31 st March 2006. It has been assumed in the preparation of this British Standard that the execution of its provisions will be
15、 entrusted to appropriately qualified and experienced people, for whose use it has been produced. WARNING. This British Standard calls for the use of procedures that may be injurious to health if adequate precautions are not taken. It refers only to technical suitability and does not absolve the use
16、r from legal obligations relating to health and safety at any stage. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard does not of itself confer immunity from legal obligation
17、s. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages 1 to 9 and a back cover. The BSI copyright displayed in this document indicates when the document was last issued.BS 7870-3.20:2001 BSI 5 February 2004 1 1 Scope This section of BS 7870 specifies
18、requirements for the construction, dimensions and mechanical and electrical properties of split concentric service cables having a rated voltage of 0.6/1(1.2) kV. NOTE The concentric layer comprises bare copper wires (earth continuity conductor) and copper wires covered with black polymeric compound
19、 (neutral conductor). It specifies requirements for the following types of cable: single phase; stranded copper or solid aluminium conductor; PVC insulation and oversheath. This section of BS 7870 is applicable to cables that are designed for a maximum continuous conductor operating temperature of 7
20、0 C and for a maximum short circuit conductor temperature of 160 C. 2 Normative references The following normative documents contain provisions which, through reference in this text, constitute provisions of this section of this British Standard. For dated references, subsequent amendments to, or re
21、visions of, any of these publications do not apply. For undated references, the latest edition of the publication referred to applies. BS 6360, Specification for conductors in insulated cables and cords. BS 7655-3.1, Specification for insulating and sheathing materials for cables Part 3: PVC insulat
22、ing compounds Section 3.1: Harmonized types. BS 7655-4.1, Specification for insulating and sheathing materials for cables Part 4: PVC sheathing compounds Section 4.1: Harmonized types. BS 7870-1, LV and MV polymeric insulated cables for use by distribution and generation utilities Part 1: General. B
23、S 7870-2:1999, LV and MV polymeric insulated cables for use by distribution and generation utilities Part 2: Methods of test. BS EN 50265-2-1, Common test methods for cables under fire conditions Test for resistance to vertical flame propagation for a single insulated conductor or cable Part 2-1: Pr
24、ocedures 1 kW pre-mixed flame. BS EN 60811-1-1:1995, Insulating and sheathing materials of electric cables Common test methods Part 1-1: General application Measurement of thickness and overall dimensions Tests for determining the mechanical properties. BS EN 60811-1-2:1995, Insulating and sheathing
25、 materials of electric cables Common test methods Part 1-2: General application Thermal ageing methods. 3 Voltage designation Cables shall be designated by the voltages U 0 , U and U m , expressed in the form U 0 /U (U m ). The voltage designation of cables in this standard is 0.6/1(1.2) kV. The rat
26、ed voltage of the cable shall be at least equal to the nominal voltage of the system for which it is intended. 4 Phase conductor The phase conductor shall be either stranded (class 2) plain annealed copper or solid (class 1) aluminium in accordance with BS 6360. Conformity shall be checked by visual
27、 examination as specified in 14.2. The d.c. resistance shall conform to the values given in Table 1 and Table 2. NOTE Other sizes and constructions may be provided by agreement between the manufacturer and the purchaser.BS 7870-3.20:2001 2 BSI 5 February 2004 5 Insulation The insulation shall be PVC
28、 compound type TI 1, conforming to the requirements of BS 7655-3.1. Insulation shall be applied by the extrusion process and shall form a compact homogeneous body. The thickness of the insulation shall be in accordance with the values specified in Table 1 and Table 2. Conformity shall be checked by
29、the test methods specified in 14.4. !The single core of all cables shall be identified by the colour brown. “ 6 Concentric layer 6.1 Neutral conductor The neutral conductor shall be manufactured from plain annealed copper wires. Conformity shall be checked by visual examination as specified in 14.3.
30、 The d.c. resistance shall conform to the values given in Table 1 and Table 2. To distinguish the neutral from the earth continuity conductor, each wire shall be covered by extrusion with a !blue “ polymeric compound, conforming to the requirements of 15.3, to a diameter approximately the same as th
31、at of the individual wires in the earth continuity conductor. NOTE The covering should not be regarded as insulation. 6.2 Earth continuity conductor The earth continuity conductor shall be manufactured from bare, plain annealed copper wires. Conformity shall be checked by visual examination as speci
32、fied in 14.3. The d.c. resistance shall conform to the values given in Table 1 and Table 2. 6.3 Non-hygroscopic string separators Non-hygroscopic string separators shall be approximately the same diameter as the individual bare wires forming the earth continuity conductor. Conformity shall be checke
33、d by visual examination as specified in 14.3. 6.4 Application of concentric layer The concentric layer shall be applied with a right-hand direction of lay. The wires forming the neutral conductor and earth continuity conductor shall be applied in individual groups over the insulation with non-hygros
34、copic string separators. Either one or two non-hygroscopic string separator(s) shall be located on either side of the group of bare copper wires to separate it from the group of covered wires. The length of lay and the number of strings shall be such that coverage of approximately 90 % is achieved.
35、Conformity shall be checked by visual examination as specified in 14.3. NOTE Examples of concentric conductor construction are given in Table 1 and Table 2. 7 Binders One or more overlapped synthetic binder tape(s) shall be applied immediately over the concentric layer. 8 Oversheath The oversheath s
36、hall be an extruded layer of PVC type TM 1, conforming to the requirements of BS 7655-4.1. NOTE Oversheaths are normally black but colours other than black may be provided by agreement between the manufacturer and the purchaser, subject to their suitability for the particular conditions under which
37、the cables are to be used. The thickness of the oversheath shall conform to the values specified in Table 1 and Table 2. Conformity shall be checked by the test methods specified in 14.5.BS 7870-3.20:2001 BSI 5 February 2004 3 9 Marking 9.1 External marking The external surface of the cable shall be
38、 legibly marked with the following elements: Element Example of marking a) Electric cable ELECTRIC CABLE b) Voltage designation 600/1 000 V c) British Standard number 1) BS 7870-3.20 d) Manufacturers identification XYZ e) Number of cores, type and nominal area of phase conductors, e.g. 1) 1 25 shall
39、 indicate a single core cable with a 25 mm 2copper phase conductor. 2) 1 25 AL shall indicate a single core cable with a 25 mm 2aluminium phase conductor. The marking of elements a) to d) shall be by embossing or by indenting on the oversheath. For cables with tabulated 2)approximate overall diamete
40、rs greater than 15 mm, elements a), b) and c) shall appear, in any sequence that is deemed neither to confuse nor to conflict, on two or more primary lines along the axis of the cable, approximately equally spaced around the circumference of the cable. Elements d) and e) shall appear, together or se
41、parately, in any sequence that is deemed neither to confuse nor to conflict, either on one of the primary lines, or on a secondary line or lines. For cables with tabulated 2)approximate overall diameters of 15 mm or less, the elements shall be arranged as for cables of greater than 15 mm diameter, e
42、xcept that the marking for elements a), b) and c) shall appear on one or more primary lines. The letters and figures shall consist of upright block characters. The characters shall have a minimum height of 3 mm. The distance between the end of one element of marking and the beginning of the next ide
43、ntical element shall be not greater than 550 mm for elements a), b) and c), and not greater than 1 100 mm for elements d) and e). Conformity shall be checked by visual examination and measurement as specified in 13.6. 9.2 Identification of year of manufacture A means of identifying the year of manuf
44、acture of the cable shall be provided throughout the length of the cable, either internally by use of an identification thread or externally by marking on the surface of the cable. If the identification mark is internal, the distance between the end of one mark and the beginning of the next mark sha
45、ll be not greater than 550 mm. If the identification is by marking on the external surface, the distance between the end of one element of marking and the beginning of the next identical element shall be not greater than 1 100 mm. Conformity shall be checked by visual examination and measurement as
46、specified in 13.6. 9.3 Mark of an approval organization If the mark of an approval organization is used, it shall be provided throughout the length of the cable, either as an identification thread or by marking on the external surface of the cable, as specified by the approval organization. If the m
47、ark is on the external surface of the cable, it shall be in the form of the symbol(s) specified by the approval organization, and the distance between the end of one element of marking and the beginning of the next identical element shall be not greater than 1 100 mm. Conformity shall be checked by
48、visual examination and measurement as specified in 13.6. 1) Marking BS 7870-3.20:2001 on or in relation to a product represents a manufacturers declaration of conformity, i.e. a claim by or on behalf of the manufacturer that the product meets the requirements of the standard. The accuracy of the cla
49、im is solely the claimants responsibility. Such a declaration is not to be confused with third-party certification of conformity. 2) See Table 1 and Table 2.BS 7870-3.20:2001 4 BSI 5 February 2004 9.4 Additional marking Where additional marking is made, it shall be throughout the length of the cable, and on the external surface of the cable, or by means of a tape or thread within the cable, or by a combination of these methods. If the additional m
