BS 7727:1994:2006 Edition
$102.76
Code of practice for installation and inspection of pre-insulated compression terminals and connectors for cables with copper conductors up to 6 mm2
| Published By | Publication Date | Number of Pages |
| BSI | 2006 | 16 |
This British Standard recommends methods and procedures applicable to installation and inspection of pre-insulated terminals and connectors for use on copper conductors of insulated cables conforming to BS EN 60228:2005, up to 6 mm2 cross-sectional area , using hand application tooling.
This standard does not apply to installations which are required to comply with BS 5G 178-1:1993 and BS 4G 178-2:1986.
Guidance for methods and procedures using hand application tooling.
PDF Catalog
| PDF Pages | PDF Title |
|---|---|
| 1 | BRITISH STANDARD BS 7727:1994 Code of practice for Installation and inspection of pre-insulated compression terminals and connectors for cables with copper conductors up to 6 mm2 |
| 2 | 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 May 1994 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: Association of Consulting Engineers Association of Manufacturers of Domestic Electrical Appliances BECCAMA (BEAMA Electrical Cable Connector and Accessories Manufacturers’ Association) British Approvals Service for Cables British Cable Makers’ Confederation British Plastics Federation British Steel Industry 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 bodes were also represented in the drafting of the standard, through subcommittees and panels: Electrical Contractors’ Association Electrical Installation Equipment Manufacturers’ Association (BEAMA Ltd.) ERA Technology Ltd. Institution of Lighting Engineers London Underground Ltd. Transmission and Distribution Association (BEAMA Ltd.) |
| 3 | Contents |
| 4 | Foreword This British Standard has been prepared under the direction of the Cables and Insulation Standards Policy Committee. BS 7727 is intended to give guidance to manufacturers and contractors who use compression terminals and connectors of the pre-in… A similar code of practice for uninsulated connectors is !BS 7609″. As a code of practice, this British Standard takes the form of guidance and recommendations. It should not be quoted as if it were a specification and particular care should be taken to ensure that claims of compliance are not misleading. The start and finish of text introduced or altered by Amendment No. 1:2006 is indicated in the text by tags !”. Minor editorial changes are not tagged. 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 to 10, 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. |
| 5 | 1 Scope This British Standard recommends methods and procedures applicable to installation and inspection of pre-insulated terminals and… This standard does not apply to installations which are required to comply with BS 5G 178-1:1993 and BS 4G 178-2:1986. 2 References 2.1 Normative references This British Standard incorporates, by dated or undated reference, provisions from other publications. These normative reference… 2.2 Informative references This British Standard refers to other publications that provide information or guidance. Editions of these publications current … 3 Definitions For the purposes of this British Standard, the following definitions apply. 3.1 pre-insulated compression joint an electrical connection made by compressively forming the insulated barrel of a terminal or connector around one or more conductors 3.2 terminal lug a connector comprising a palm and a barrel, for connecting a conductor to an equipment terminal 3.3 splice a device used to permanently connect conductors to each other 3.4 disconnect connector a device used to connect a conductor to another conductor or equipment terminal fitted with a similar connector having mating parts of opposite gender. Such connection or disconnection may only be suitable for a limited number of operations 3.5 barrel part of a connector designed to accommodate the conductor 3.6 palm part of a terminal lug formed flat to make a bolted connection to an equipment terminal 3.7 insulation sleeve cylindrical insulation sleeve surrounding the compression barrel and through which the compressed connection is made. The insulation may be extended to protect the mating part of a connector 3.8 insulation grip sleeve an optional metal sleeve interposed between the compression barrel and insulation for the purpose of providing a positive retention of the wire insulation within the insulation compression area 3.9 compression sleeve a metal sleeve often used to improve compression properties of the spring material when using mating disconnect devices 4 Marking Each compression connector and its packaging should be clearly marked with the supplier’s identification (Figure 1). Reference s… |
| 6 | Figure 1 – Example of identification marking 5 Selection of styles There are various styles of terminals and connectors available; some of these are described in Annex A . If there is any doubt about correct selection, advice should be sought from the supplier or manufacturer. Insulation entry diameter should be checked to ensure that the selected wire insulation can be accommodated. Flared and straight entry variants are available (Figure 2). Figure 2 – Examples of styles 6 Compression tools Advice should be sought from the terminal supplier or manufacturer, if there is any doubt about the correct selection of the too… Locators are available for various terminal types and, as they facilitate precise location during compression, they promote cons… Tools should be regularly maintained, tested and where required, certified. Further information on maintenance, testing and certification is given in Annex B . 7 Current rating Current ratings are dependent upon the conductors in use, the environment and the permitted temperature rise. Correctly designed… 8 Preparation Cable should be cut to length and stripped squarely and cleanly without damage to conductors or insulation (Figure 4). There sho… If the compression tool is fitted with a locator (Figure 6) it should be appropriate to the style of terminal being compressed. … |
| 7 | Figure 3 – Examples of compression tools Figure 4 – Example of correct and incorrect stripping of insulation Figure 5 – Example of correct bare conductor protrusion Figure 6 – Example of a tool with a locator fitted Figure 7 – Example of a tool with insulation thickness adjustment |
| 8 | 9 Compression The connector should be inserted into the tool die-space (Figure 8); if a locator is present it should be used. If a locator is … The handles should then be closed until the full closure device permits them to be opened, releasing the compressed connector. 10 Inspection Figure 9 shows correct compression features and Figure 10 shows common faults. The compressed connector should be inspected to check the following. a) The correct connector has been used for the conductor size (see clause 4). b) Compression die identifier markings show that the correct dies have been used for the connector size. c) Correct positioning of compressed areas, ensuring that the conductor compression is central to the conductor barrel length and in the correct plane. d) Approximately 1 mm of conductor shows at the barrel end or that, if a wire stop is present, the conductor abuts it. e) The wire insulation is fully inserted into the entry of the insulation sleeve and is adequately secured or supported, depending upon the connector construction. f) There is no apparent damage to conductors or insulation and that no stray strands of conductor are visible. Quality control procedures should include the periodic sampling of completed work for tensile testing and voltage drop testing a… |
| 9 | Figure 8 – Example of correct insertion into a compression tool |
| 10 | Figure 9 – Examples of correct compression Figure 10 – Examples of common faults |
| 11 | Annex A (informative) Construction of pre-insulated terminals, splices and connectors A.1 Pre-insulated copper compression terminals (see Figure A.1) The compression area is a cylindrical barrel formed from tightly butted sheet copper, the seam of which may be brazed. One end o… A tubular insulating sleeve is fitted around the barrel, usually flush with the junction of barrel and palm, extending past the … PVC is commonly used; it has excellent insulation and mechanical properties and is little affected by moisture. Other insulation… It is essential that nylon insulated products are not exposed to high or low humidity prior to use. In addition to the insulating sleeve, there may be a metal sleeve interposed between the insulating sleeve and the barrel, exten… Insulation sleeving is normally coloured to indicate the applicable conductor size range. A.2 Pre-insulated splices (see Figure A.2) A lap or parallel splice has a short barrel of sufficient size to connect the sum of the conductors to be joined. The barrel has… A closed end splice has a similar barrel, but the insulation is formed or moulded to allow wire entry from one end only. Installation is made with a single compression of the conductor only. A through or butt splice has a longer barrel with two compression areas separated by an indent which acts as a conductor stop. T… The copper barrels of these types are frequently made from tubular copper, but can be from rolled sheet with tightly butted seams, which may be brazed. A.3 Pre-insulated disconnect connectors (see Figure A.3) Mating connectors are usually flat male and female connections with male tab dimensions of 2.8, 4.8, 6.3 and 9.5 mm wide and thi… Because of the necessity to maintain contact pressure of the mating connectors, these are normally made from a suitable grade of… The insulation sleeve of mating connectors is often extended to cover and insulate the mating parts. The process of compressing mating connectors using the above style of composite construction is more critical than with copper b… |
| 12 | Figure A.1 – Examples of pre-insulated compression terminal Figure A.2 – Examples of pre-insulated splices |
| 13 | Figure A.3 – Examples of pre-insulated disconnect connectors Annex B (informative) Maintenance, testing and certification of tooling B.1 General All tooling used in the application of cable connectors should be kept in a good state of repair and adjustment. Tools and assoc… At suitable intervals of up to 12 months maximum, depending upon tool types, usage and manufacturer’s recommendations, the tools… The authority should maintain records of tool history indexed by serial numbers which are engraved on tools by the authority. Th… When submitting tooling for maintenance, test and certification, it should be accompanied by specimens of work performed by the … B.2 Examination of initial specimens Upon receipt by the authority, initial specimens should be examined in accordance with clause 10 or another recognized standard … |
| 14 | Tools and accompanying dies should be examined carefully for missing parts, damage and excessive wear. Interchangeable dies shou… The full closure mechanism (ratchet) should be tested for correct operation and release point. If necessary, it should be adjusted or replaced. With the tool in the closed position, die compression cavities should be checked with the aid of “go/no-go” gauges. If out of to… B.3 Preparation and testing of compressed specimens Three specimens should be prepared for each die using the appropriate minimum wire size and should be tested in accordance with … Details of the above operations should be entered on the Tool History Record, the reference number of which will be found engrav… B.4 Certificate The inspection and test certificate should show the following: a) user (customer) name, address, contact name and order number; b) date, certificate serial number, tool history reference number, user’s tool reference number (if any), the tool manufacturer and part number; c) style of tool with completed check-list of operations; d) details of any special requirements, non-typical applications, etc; e) details of tensile test, showing the reference standard, the standard acceptance level and the results; manufacturer and part number of terminals, manufacturer and details of cables; f) comments to the user; g) authorized signature on behalf of the maintenance, test and certification authority; h) quality system status of inspection and certification authority. |
| 15 | List of references (see clause 2) Normative references BSI publications BRITISH STANDARDS INSTITUTION, London !BS EN 60228:2005, Conductors of insulated cables. ” Informative references BSI publications BRITISH STANDARDS INSTITUTION, London !BS 5057:1992, Specification for flat, quick-connect terminations. ” BS 7609:1992, Code of practice for installation and inspection of uninsulated compression and mechanical connectors for power cables with copper or aluminium conductors. BS 5G 178, Crimped joints for aircraft electric cables and wires. BS 5G 178-1:1993, Specification for design requirements (including tests) for components and tools. BS 4G 178-2:1986, Specification for control of crimping (including user control tests). !BS EN 61238-1:2003, Compression and mechanical connectors for power cables for rated voltages up to 36 kV (Um = 42 kV) – Part 1: Test methods and requirements. BS EN ISO 9000:2005, Quality management systems – Fundamentals and vocabulary. ” |
| 16 | BS 7727:1994 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. It is incorporated by Royal Charter. Revisions British Standards are updated by amendment or revision. Users of British Standards should make sure that they possess the latest amendments or editions. It is the constant aim of BSI to improve the quality of our products and services. We would be grateful if anyone finding an ina… BSI offers members an individual updating service called PLUS which ensures that subscribers automatically receive the latest editions of standards. Buying standards Orders for all BSI, international and foreign standards publications should be addressed to Customer Services. Tel: 0181 996 7000. Fax: 0181 996 7001. In response to orders for international standards, it is BSI policy to supply the BSI implementation of those that have been published as British Standards, unless otherwise requested. Information on standards BSI provides a wide range of information on national, European and international standards through its Library and its Technical… Subscribing members of BSI are kept up to date with standards developments and receive substantial discounts on the purchase pri… Copyright Copyright subsists in all BSI publications. BSI also holds the copyright, in the UK, of the publications of the international st… This does not preclude the free use, in the course of implementing the standard, of necessary details such as symbols, and size,… If permission is granted, the terms may include royalty payments or a licensing agreement. Details and advice can be obtained from the Copyright Manager. Tel: 0181 996 7070. |
