BS-7655-3.2-1993.pdf
BRITISH STANDARD BS 7655-3.2: 1993 Specification for Insulating and sheathing materials for cables Part 3: PVC insulating compounds Section 3.2 Hard grade types Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 11:56:44 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7655-3.2:1993 This British Standard, having been prepared under the direction of the Cables and Insulation Standards Policy Committee, was published under the authority of the Standards Board and comes into effect on 15 April 1993 © BSI 01-2000 The following BSI references relate to the work on this standard: Committee reference CIL/20 Draft for comment 92/25662 DC ISBN 0 580 22038 9 Committees responsible for this British Standard The preparation of this British Standard was entrusted by the Cables and Insulation Standards Policy Committee (CIL/-) to Technical Committee CIL/20, upon which the following bodies were represented: Aluminium Federation Association of Consulting Engineers Association of Manufacturers of Domestic Electrical Appliances British Approvals Service for Cables British Cable Makers Confederation British Plastics Federation British Steel Industry Department of the Environment (Property Services Agency) Department of Trade and Industry (Consumer Safety Unit, CA Division) Electricity Association Engineering Equipment and Materials Users Association Institution of Electrical Engineers London Regional Transport The following bodies were also represented in the drafting of the standard, through subcommittees and panels: British Railways Board British Rubber Manufacturers Association Ltd. British Telecommunications plc ERA Technology Ltd. GAMBICA (BEAMA Ltd.) Institution of Incorporated Executive Engineers London Underground Ltd. Queen Mary and Westfield College Telecommunications Cables Group of BCMC Warrington Fire Research Centre Amendments issued since publication Amd. No.DateComments Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 11:56:44 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7655-3.2:1993 © BSI 01-2000i Contents Page Committees responsibleInside front cover Forewordii 1Scope1 2Normative references1 3Definitions1 4Composition1 5Colours1 6Test requirements for physical and electrical properties1 Table 1 Type of hard grade PVC insulation1 Table 2 Test methods1 Table 3 Test requirements2 Table 4 Tolerances on temperature values2 List of referencesInside back cover Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 11:56:44 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7655-3.2:1993 ii © BSI 01-2000 Foreword This Section of BS 7655 has been prepared under the direction of the Cables and Insulation Standards Policy Committee. This Section specifies the physical and electrical properties of hard grade PVC insulating compound type 2. For a general introduction to the BS 7655 series and a list of Parts and Sections, Part 0 should be consulted. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages 1 and 2, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover. Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 11:56:44 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7655-3.2:1993 © BSI 01-20001 1 Scope This Section of BS 7655 specifies the physical and electrical properties of the hard grade PVC insulating compound given in Table 1. The relevant test methods for verification of compliance are given in BS 6469. This Section is to be used in conjunction with BS 7655-0. Table 1 Type of hard grade PVC insulation 2 Normative references This Section of BS 7655 incorporates by dated or undated reference, provisions from other publications. These normative references are cited at the appropriate places in the text and the publications are listed on the inside back cover. For a dated reference, only the edition cited applies; any subsequent amendments to or revisions of the publication apply to this British Standard only when incorporated in the reference by amendment or revision. For undated references, any amendment to, or the latest edition of, the cited publications applies. 3 Definitions For the purposes of this Section of BS 7655, the definitions given in BS 1755-1, BS 1755-2, BS 3558 and BS 4727-2:Group 08 apply, together with the following. 3.1 variation the difference between the median value after ageing and the median value without ageing expressed as a percentage of the latter 3.2 median value when several test results have been obtained and ordered in an increasing or decreasing succession, the median is the middle value if the number of available values is odd and is the mean of the two middle values if the number is even 4 Composition The insulation shall consist of a compound based on one of the following materials suitably compounded and processed to conform to this standard: a) polyvinyl chloride (PVC); or b) a copolymer of vinyl chloride; or c) a mixture of materials a) and b). 5 Colours Opaque insulation shall be of a colour that reasonably matches one of the colours given in BS 6746C. NOTEThere is no requirement for the colour of transparent insulation. 6 Test requirements for physical and electrical properties 6.1 General 6.1.1 The test methods shall be as specified in Table 2 and the methods of sampling and pre-conditioning shall be as described in 6.2 and 6.3. The temperatures used for the test methods shall conform to the conditions specified in 6.4. Table 2 Test methods (in accordance with BS 6469 unless otherwise stated) 6.1.2 When tested by the methods specified in 6.1.1 the properties shall be in accordance with the requirement given in Table 3 for the particular type of material. 6.2 Sampling Unless otherwise stated in the particular specification for the cable, the tests on insulation shall be made on samples from each core if the cable has one, two or three cores and on samples from three cores (of differing colours, if any) if the cable has more than three cores. 6.3 Pre-conditioning The tests shall be carried out not less than 16 h after extrusion. Type Maximum material operating temperature °C General application 270Hard grade Test Method SectionClause Properties in the state as delivered Tensile strength and elongation at break 1.1:19929 Bending test at low temperature 1.4:19928.1 Elongation test at low temperature 1.4:19928.3 Pressure test at high temperature 3.1:19928.1 Resistance to cracking3.1:19929.1 Loss of mass test3.2:19928.1 Hot deformation test99.1:199210 Insulation resistance test99.2:19928 Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 11:56:44 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7655-3.2:1993 2 © BSI 01-2000 Table 3 Test requirements 6.4 Temperatures for test methods 6.4.1 Ambient temperature Tests shall be made at an ambient temperature within the range 5 °C to 35 °C unless otherwise specified in the details for the particular test. 6.4.2 Tolerances on temperature values Unless otherwise stated in the particular specification the tolerances on temperature values quoted in the test methods shall be as given in Table 4. Table 4 Tolerances on temperature values Test Requirements for insulation type 2 Properties in the state as delivered Minimum tensile strengthN/mm218.5 Minimum elongation at break%125 Bending test at low temperature Temperature°C 15 Requirementno cracks Elongation test at low temperature Temperature°C 15 Minimum elongation without break%20 Pressure test at high temperature Force exerted by the blade a Duration of heating under load a Temperature°C 80 Maximum indentation%50 Resistance to cracking Temperature°C 150 Requirementno cracks Loss of mass test Temperature°C 80 Durationh 7 × 24 Maximum loss of massmg/cm22 Hot deformation testb Maximum deformation%30 Insulation resistance test Temperature°C 20 Minimum K valueM7·km 350 a See 8.1 of BS 6469-3.1:1992. b Only for specified radial thicknesses less than 0.4 mm. Specified temperature, t °C Tolerance °C 40 k t k0± 2 0 150± 3 Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 11:56:44 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7655-3.2:1993 © BSI 01-2000 List of references (see clause 2) Normative references BSI standards publications BRITISH STANDARDS INSTITUTION, London BS 1755, Glossary of terms used in the plastics industry. BS 1755-1:1982, Polymer and plastics technology. BS 1755-2:1974, Manufacturing processes. BS 3558:1980, Glossary of rubber terms. BS 4727, Glossary of electrotechnical, power, telecommunication, electronics, lighting and colour terms. BS 4727-2, Terms particular to power engineering. BS 4727-2:Group 08:1986, Electric cable terminology. BS 6469, Common test methods for insulating and sheathing materials of electric cables. BS 6469-1, Methods for general application. BS 6469-1.1:1992, Measurement of thickness and overall dimensions Tests for determining the mechanical properties. BS 6469-1.4:1992, Tests at low temperature. BS 6469-3, Methods specific to PVC compounds. BS 6469-3.1:1992, Pressure test at high temperature Tests for resistance to cracking. BS 6469-3.2:1992, Loss of mass test Thermal stability test. BS 6469-99, Test methods used in the United Kingdom but not specified in Parts 1 to 5. BS 6469-99.1:1992, Non-electrical tests. BS 6469-99.2:1992, Electrical tests. BS 6746C:1969, Colour chart for PVC insulation and sheath of electric cables. BS 7655, Specification for insulating and sheathing materials for cables. BS 7655-0:1993, General introduction. Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 11:56:44 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7655-3.2: 1993 BSI 389 Chiswick High Road London W4 4AL BSI British Standards Institution BSI is the independent national body responsible for preparing British Standards. It presents the UK view on standards in Europe and at the international level. 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