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1、BRITISH STANDARD CONFIRMED OCTOBER 1990 BS 5345-6: 1978 Reprinted, incorporating Amendment No. 1 and Corrigendum No. 1 Code of practice for The selection, installation and maintenance of electrical apparatus for use in potentially explosive atmospheres (other than mining applications or explosives p
2、rocessing) Part 6: Recommendations for type of protection “e” Increased safety UDC 696.6:621.3 7:614.83 Licensed Copy: sheffieldun sheffieldun, na, Mon Dec 04 12:25:51 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 5345-6:1978 This British Standard, having been prepared under the direction of the Gen
3、eral Electrotechnical Engineering Standards Committee, was published under the authority of the Executive Board on 31 March 1978 BSI 02-2000 The following BSI references relate to the work on this standard: Committee reference GEL/114 Draft for comment 75/20797 DC ISBN 0 580 10164 9 Cooperating orga
4、nizations The General Electrotechnical Engineering Standards Committee, under whose direction this British Standard was prepared, consists of representatives from the following Government departments and scientific and industrial organizations: The organizations marked with an asterisk in the above
5、list, together with the following, were directly represented on the committee entrusted with the preparation of this British Standard: British Electrical and Allied Manufacturers Electronic Components Industry Federation* Association (BEAMA)*Electronic Engineering Association British Radio Equipment
6、 Manufacturers Engineering Equipment Users Association* AssociationHealth and Safety Executive* British Steel CorporationHome Office Department of Energy (Electricity)Institution of Electrical Engineers* Electric Cable Makers Confederation*Ministry of Defence* Electrical Contractors Association*Nati
7、onal Coal Board* Electrical Contractors Association of ScotlandOil Companies Materials Association* Electrical Research Association*Post Office* Electricity Supply Industry in England and Telecommunication Engineering and Wales*Manufacturing Association (TEMA)* Association of Consulting EngineersDep
8、artment of the Environment Association of Mining Electrical and Department of the Environment (Building Mechanical EngineersResearch Establishment) British Electrical Systems Association (Fire Research Station) (BEAMA)Department of Trade (Marine Division) British Gas CorporationFire Offices Committe
9、e British Industrial Measuring and Control Fire Protection Association Apparatus Manufacturers AssociationGeneral Council of British Shipping British Industrial Truck AssociationInstitute of Petroleum CBMPEInstitution of Gas Engineers Chief and Assistant Chief Fire Officers Institution of Mining Eng
10、ineers AssociationLighting Industry Federation Ltd. Council for Electrical Equipment for Rotating Electrical Machines Association Flammable Atmospheres (BEAMA)(BEAMA) Council of Underground Machinery Scientific Instrument Manufacturers ManufacturersAssociation Department of Energy (Petroleum) (OIL)
11、Amendments issued since publication Amd. No.Date of issueComments 5557November 1989 7957 Corr.November 1992 Indicated by a sideline in the margin Licensed Copy: sheffieldun sheffieldun, na, Mon Dec 04 12:25:51 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 5345-6:1978 BSI 02-2000i Contents Page Coope
12、rating organizationsInside front cover Forewordii 0Introduction1 Section 1. General principles 1Scope2 2References2 3Definitions and explanation of terms2 4Description of technique3 5Relevant specifications3 Section 2. Selection of apparatus 6General3 7Permissible zones of use3 8Temperature classifi
13、cation4 9Apparatus subgrouping4 10Environmental conditions5 11Requirements for certification of apparatus5 12Rotating machines and similar apparatus5 Section 3. Installation requirements 13General5 14Automatic electrical protection5 15Wiring systems5 16Installation of metallic conduit systems5 17Ins
14、tallation of cables5 18Conductor terminations6 Section 4. Inspection maintenance and testing 19General6 20Initial and periodic inspections6 21Maintenance7 Appendix A Selection of increased safety cage motors and associated protection devices8 Appendix B Marking of apparatus12 Appendix C Resistance t
15、o impact14 Appendix D Resistance to chemical attack14 Figure 1 Minimum tE time for motors in relation to IA/IN9 Table 1 Inspection schedule; apparatus with type of protection “e”: increased safety7 Table 2 Class of insulating material and limiting temperature9 Publications referred toInside back cov
16、er Licensed Copy: sheffieldun sheffieldun, na, Mon Dec 04 12:25:51 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 5345-6:1978 ii BSI 02-2000 Foreword Many gases, vapours, mists and dusts encountered in industry are flammable. When ignited, they may burn readily and with considerable explosive force i
17、f mixed with air in the appropriate proportions. It is often necessary to use electrical apparatus in locations where such flammable materials may be present, and appropriate precautions should therefore be taken to ensure that all such apparatus is adequately protected in order to reduce the likeli
18、hood of ignition of any external explosive atmosphere. When using electrical apparatus, potential ignition sources include electrical arcs and sparks, hot surfaces and, in certain circumstances, frictional sparks. In general, electrical safety is ensured by implementing one of two procedures. Either
19、 the electrical apparatus should be located, whenever practicable, outside hazardous areas; or the electrical apparatus should be designed, installed and maintained in accordance with measures recommended for the area in which the apparatus is located. Several techniques are available for the protec
20、tion of electrical apparatus in hazardous areas. Some of these techniques (or “types of protection” as they are known) have been used for many years and have come to be regarded as traditional. Other types of protection have been introduced only recently. This code of practice describes the basic sa
21、fety features of these types of protection, full details of which are given in the relevant standards, and recommends the selection, installation and maintenance procedures that should be adopted to ensure the safe use of electrical apparatus in hazardous areas. This code therefore takes account of
22、the significant developments that have taken place in area classification and in the design, manufacture and use of electrical apparatus for hazardous areas since the preparation of the earlier code of practice CP 1003. It is important to note that this code of practice deals with explosion hazards
23、due to the presence of flammable gas-air mixtures; it does not provide guidance on the extra precautions to be taken where such gases involve a toxic hazard. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for thei
24、r 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 14, an inside back cover and a back cover. This standard has been updated (se
25、e copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover. Licensed Copy: sheffieldun sheffieldun, na, Mon Dec 04 12:25:51 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 5345-6:1978 BSI 02-20001 0 Introduction This document is
26、Part 6 of code of practice BS 5345. The code gives guidance in the selection, installation and maintenance of electrical apparatus for use in areas where flammable materials are generated, processed, handled or stored, and that are therefore potentially hazardous. In common with the earlier code of
27、practice for the use of electrical apparatus in hazardous areas (CP 1003-1:1964, CP 1003-2:1966 and CP 1003-3:1967), the present code is divided into a number of Parts. Each Part deals with the installation and maintenance requirements appropriate to one of the types of protection that may be used t
28、o achieve electrical safety, or with basic requirements and considerations that are fundamental to the use of electrical apparatus in hazardous areas and that therefore provide the basis for the other Parts of the code. The full list of Parts is as follows: Part 1: General recommendations; Part 2: C
29、lassification of hazardous areas1); Part 3: Installation and maintenance requirements for electrical apparatus with type of protection “d”. Flameproof enclosure1); Part 4: Installation and maintenance requirements for electrical apparatus with type of protection “i”. Intrinsically safe apparatus and
30、 systems; Part 5: Installation and maintenance requirements for electrical apparatus with type of protection “p”. Pressurization and continuous dilution1); Part 6: Recommendations for type of protection “e”. Increased safety; Part 7: Installation and maintenance requirements for electrical apparatus
31、 with type of protection N1); Part 8: Installation and maintenance requirements for electrical apparatus with type of protection “s”. Special protection1); Part 9: Installation and maintenance requirements for electrical apparatus with type of protection “o”. Oil-immersed apparatus, and with type of
32、 protection “q”. Sand-filled apparatus1). This Part of the code should be read in conjunction with the other Parts, particularly Parts 1 and 2 which, taken together, describe the fundamental considerations that affect the selection, installation and maintenance of all electrical apparatus used in ha
33、zardous areas. BS 5345 is based on the concept of area classification which recognizes the differing degrees of probability with which explosive (flammable) concentrations of flammable gas or vapour may arise in installations in terms of both the frequency of occurrence and the probable duration of
34、existence on each occasion. The detailed considerations that should be taken into account in deciding on an area classification are described in Part 2 of the code. For completeness, and for the convenience of readers, the definitions appropriate to area classification are repeated here. It should b
35、e noted that whereas, formerly, classified areas were known as Divisions, they are now called Zones. Three Zones are recognized, i.e.: It should be noted that this concept of area classification deals only with risks due to flammable gases and vapours and, by implication, mists. It does not deal wit
36、h flammable dusts, which may lie quiescent for long periods of time until disturbed into suspension by a suitable mechanism. An area classification concept is being developed for dusts. By implication, an area that is not classified as Zone 0, 1 or 2 is deemed to be a non-hazardous or safe area. If
37、doubt exists as to the classification of an area that is judged to be hazardous or potentially hazardous, guidance should be sought at an early stage from the authority having jurisdiction in the industry or area concerned (see Parts 1 and 2 of the code). Electrical apparatus used in each of the cla
38、ssified Zones should be suitably protected by design and manufacture, and should also be installed and maintained in a manner to ensure its safe use. BS 5345, in offering guidance in the selection, installation and maintenance of suitably protected apparatus, replaces CP 1003 and should be used for
39、all new installations. It should also be used for changes to existing installations, though it is recognized that minor changes only to certain existing installations may need to be made in accordance with the recommendations of the earlier code. It is intended, however, that CP 1003-1, CP 1003-2 an
40、d CP 1003-3 will eventually be withdrawn from use. 1) In course of preparation. Zone 0In which an explosive gas-air mixture is continuously present or present for long periods. Zone 1In which an explosive gas-air mixture is likely to occur in normal operation. Zone 2In which an explosive gas-air mix
41、ture is not likely to occur in normal operation, and if it occurs it will only exist for a short time. Licensed Copy: sheffieldun sheffieldun, na, Mon Dec 04 12:25:51 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 5345-6:1978 2 BSI 02-2000 Notwithstanding application of the installation recommendatio
42、ns of this code to existing installations, the recommendations for maintenance should be applied to all electrical apparatus and installations, irrespective of age and date of installation. It should also be noted that the installation and maintenance recommendations given in the code are supplement
43、ary to, and not alternative to, requirements that would apply to general industrial installations (see also Part 1 of the code). Section 1. General principles 1 Scope This Part of BS 5345 describes the concept of ensuring electrical safety in hazardous areas by means of type of protection “e”: incre
44、ased safety, and gives guidance on the selection, installation and maintenance of this type of electrical apparatus. This code does not apply to the underground mining industry, where other precautions are necessary, though it is recognized that the code may be applied to the surface installations o
45、f mines. Apparatus with type of protection “e”: increased safety is designed for use in areas with flammable gas and vapour risks. For the use of this apparatus in areas with flammable dust risks see Part 10 of the code. 2 References The titles of the publications referred to in this code are listed
46、 on the inside back cover. 3 Definitions and explanation of terms The definitions and terms generally applicable to hazardous areas and electrical apparatus used therein are included in Part 1 of the code, to which reference should be made. The definitions and terms that are particularly relevant to
47、 individual types of protection are given in the appropriate Parts of the code. For the purposes of this Part, the following definitions and terms apply. 3.1 type of protection “e”: increased safety a method of protection by which additional measures are applied to electrical apparatus to give incre
48、ased security against the possibility of excessive temperatures and of the occurrence of arcs and sparks during the service life of the apparatus. It applies only to electrical apparatus, no parts of which produce sparks or arcs or exceed the limiting temperature in normal service 3.2 clearance the
49、shortest distance through air between two conducting parts 3.3 creepage distance the shortest distance between two conducting parts along the surface of the insulating parts 3.4 dynamic current limit Idyn the peak value of the maximum alternating current the dynamic effect of which the electrical apparatus can sustain without damage 3.5 limiting temperature the maximum permissible temperature for apparatus or parts of apparatus. It is determined by: a) the danger of ignition of the explosive gas-air mixture; b) the thermal stability of the mater