1、 IEC 60079-18 Edition 4.0 2014-12 REDLINE VERSION Explosive atmospheres Part 18: Equipment protection by encapsulation “m” IEC 60079-18:2014-12 RLV(en) colour inside THIS PUBLICATION IS COPYRIGHT PROTECTED Copyright 2014 IEC, Geneva, Switzerland All rights reserved. Unless otherwise specified, no pa
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10、sc If you wish to give us your feedback on this publication or need further assistance, please contact the Customer Service Centre: csciec.ch. IEC 60079-18 Edition 4.0 2014-12REDLINE VERSIONExplosive atmospheres Part 18: Equipment protection by encapsulation “m” INTERNATIONAL ELECTROTECHNICAL COMMIS
11、SION RM ICS 29.260.20 PRICE CODE ISBN 978-2-8322-2078-8 Registered trademark of the International Electrotechnical Commission Warning! Make sure that you obtained this publication from an authorized distributor. colour inside 2 IEC 60079-18:2014 RLV IEC 2014 CONTENTS FOREWORD . 5 1 Scope 8 2 Normati
12、ve references. 8 3 Terms and definitions 9 4 General . 11 4.1 Level of protection (equipment protection level (EPL) 11 4.2 Additional requirements for levels of protection “ma” and “mb” . 11 4.3 Additional requirements for level of protection “ma” 11 4.4 Rated voltage and prospective short circuit c
13、urrent 11 5 Requirements for compounds . 11 5.1 General . 11 5.2 Specification . 12 5.3 Properties of the compound . 12 5.3.1 Water absorption 12 5.3.2 Dielectric strength 12 6 Temperatures 12 6.1 General . 12 6.2 Determination of the limiting temperatures . 13 6.2.1 Maximum surface temperature . 13
14、 6.2.2 Temperature of the compound 13 6.3 Temperature limitation . 13 7 Constructional requirements 13 7.1 General . 13 7.2 Determination of faults 14 7.2.1 Fault examination . 14 7.2.2 Components considered as not subject to fail . 14 7.2.3 Isolating components . 15 7.2.4 Infallible separation dist
15、ances 15 7.3 Free space in the encapsulation 17 7.3.1 Group III “m” equipment . 17 7.3.2 Group I and Group II “m” equipment . 17 7.4 Thickness of the compound . 18 7.4.1 “m” equipment 18 7.4.2 Windings for electrical machines 20 7.4.3 Rigid, multi-layer printed wiring boards with through connections
16、 20 7.5 Switching contacts 22 7.5.1 General . 22 7.5.2 Level of protection “ma” . 22 7.5.3 Level of protection “mb” . 23 7.5.4 Level of protection “mc” 23 7.6 External connections . 23 7.6.1 General . 23 7.6.2 Additional requirements for “ma” equipment 23 7.7 Protection of bare live parts . 23 IEC 6
17、0079-18:2014 RLV IEC 2014 3 7.8 Cells and batteries 24 7.8.1 General . 24 7.8.2 Prevention of gassing . 24 7.8.3 Protection against inadmissible temperatures and damage to the cells or batteries . 24 7.8.4. Reverse current . 25 7.8.5 Current limitation . 25 7.8.6 Protection against the polarity inve
18、rsion and deep discharge of the cells . 25 7.8.7 Charging of cells or batteries 26 7.8.8 Requirements for control safety devices for cells or batteries 26 7.9 Protective devices . 26 7.9.1 General . 26 7.9.2 Electrical protective devices . 27 7.9.3 Thermal protective devices . 28 7.9.4 Built-in prot
19、ective devices 28 8 Type tests . 29 8.1 Tests on the compound . 29 8.1.1 Water absorption test . 29 8.1.2 Dielectric strength test . 29 8.2 Tests on the apparatus 29 8.2.1 Test sequence . 29 8.2.2 Maximum temperature 29 8.2.3 Thermal endurance test 30 8.2.4 Dielectric strength test . 30 8.2.5 Cable
20、pull test 31 8.2.6 Pressure test for Group I and Group II electrical equipment 32 8.2.7 Test for resettable thermal protective device . 32 8.2.8 Sealing test for built-in protective devices . 33 9 Routine verifications and tests . 33 9.1 Visual inspections . 33 9.2 Dielectric strength test 33 10 Mar
21、king . 34 Annex A (informative) Basic requirements for compounds for “m” equipment . 35 Annex B (normative informative) Allocation of test samples . 36 Bibliography . 37 Figure 1 Dimensional key for thickness through the compound 19 Figure 2 Minimum distances for multi-layer printed wiring boards 22
22、 Figure 3 Fitting of blocking diodes 25 Figure A.1 Basic requirements for compounds for “m” equipment 35 Table 1 Distances through the compound . 16 Table 2 Minimum thickness of compound adjacent to free space for Group III “m” equipment 17 Table 3 Minimum thickness of compound adjacent to free spac
23、e for Group I and Group II “m” equipment . 18 Table 4 Thickness of the compound . 20 4 IEC 60079-18:2014 RLV IEC 2014 Table 5 Minimum distances for multi-layer printed wiring boards . 21 Table 6 Test pressure 32 Table B.1 Allocation of test samples . 36 IEC 60079-18:2014 RLV IEC 2014 5 INTERNATIONAL
24、 ELECTROTECHNICAL COMMISSION _ EXPLOSIVE ATMOSPHERES Part 18: Equipment protection by encapsulation “m” FOREWORD 1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising all national electrotechnical committees (IEC National Committees). The o
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35、 version is not an official IEC Standard and is intended only to provide the user with an indication of what changes have been made to the previous version. Only the current version of the standard is to be considered the official document. This Redline version provides you with a quick and easy way
36、 to compare all the changes between this standard and its previous edition. A vertical bar appears in the margin wherever a change has been made. Additions and deletions are displayed in red, with deletions being struck through. 6 IEC 60079-18:2014 RLV IEC 2014 Standard IEC 60079-18 has been prepare
37、d by IEC technical committee 31: Equipment for explosive atmospheres. This fourth edition cancels and replaces the third edition of IEC 60079-18 (2009), and constitutes a technical revision. This International Standard is to be used in conjunction with IEC 60079-0, Explosive atmospheres Part 0: Equi
38、pment-General requirements. This edition includes the following significant technical changes with respect to the previous edition: Type Explanation of the significance of the changes Clause Minor and editorial changes Extension Major technical changes Definitions deleted and moved to IEC 60079-0 3
39、X Heading modified /added to clarify which requirements are additional requirements for “ma” level of protection only 4 X Thermal conductivity added 5.2 X Note added that it is not a requirement of this standard that conformity to the manufacturers specification of the compound needs to be verified
40、5.3.2 X Clarification added 6.2.2 X Clarification added 7.1 X For the determination of faults options added and clarification given 7.2 X Additional information included in Figure 1 7.4.1 X “Varnish and similar coatings are not considered to be solid insulation.” was added in this section and delete
41、d in the definition on 3.8 7.4.2 X For rigid, multi-layer printed wiring boards with through connections additional standards added 7.4.3.1 X Protection against inadmissible temperatures and damage to the cells 7.8.3 C1 Electrical protective devices clarified and additional possibilities added 7.9.2
42、 X Thermal protective devices clarified and additional possibilities added 7.9.3 X 2/3 voltage limitation deleted 7.9.3 X Determination of the maximum temperature for “Da” fixed 8.2.2 C2 Stabilization of the temperature 8.2.2 C3 Thermal endurance to heat 8.2.3.1 X Temperature fixed as reference serv
43、ice temperatures and tests given as alternatives 8.2.3.1.1 X For the dielectric strength test procedure alternative possibilities added 8.2.4.1 X Alternative test methods for the required pressure test for Group I and Group II electrical equipment added 8.2.6 X Sealing test for build-in protective d
44、evices 8.2.8 X For the dielectric strength test procedure alternative possibilities added 9.2 X Marking 10 X X IEC 60079-18:2014 RLV IEC 2014 7 Explanation of the Types of Significant Changes: A) Definitions 1. Minor and editorial changes: Clarification Decrease of technical requirements Minor techn
45、ical change Editorial corrections These are changes which modify requirements in an editorial or a minor technical way. They include changes of the wording to clarify technical requirements without any technical change, or a reduction in level of existing requirement. 2. Extension: Addition of techn
46、ical options These are changes which add new or modify existing technical requirements, in a way that new options are given, but without increasing requirements for equipment that was fully compliant with the previous standard. Therefore, these will not have to be considered for products in conformi
47、ty with the preceding edition. 3. Major technical changes: addition of technical requirements increase of technical requirements These are changes to technical requirements (addition, increase of the level or removal) made in a way that a product in conformity with the preceding edition will not alw
48、ays be able to fulfil the requirements given in the later edition. These changes have to be considered for products in conformity with the preceding edition. For these changes additional information is provided in item B) below. Note These changes represent current technological knowledge. However,
49、these changes should not normally have an influence on equipment already placed on the market. B) Information about the background of Major technical changes C1 Clause 7.8.3 modified and additional requirements added for cells or batteries C2 The flexibility given in IEC 60079-0 is replaced by a min. requirement. For level of protection “ma” equipment, designed for EPL “Da” the maximum surface temperature shall be determined with the equipment mounted in accordance with the manufacturer
