1、 IEC 60079-7 Edition 5.0 2015-06 INTERNATIONAL STANDARD Explosive atmospheres Part 7: Equipment protection by increased safety e IEC 60079-7:2015-06(en) THIS PUBLICATION IS COPYRIGHT PROTECTED Copyright 2015 IEC, Geneva, Switzerland All rights reserved. Unless otherwise specified, no part of this pu
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10、h to give us your feedback on this publication or need further assistance, please contact the Customer Service Centre: csciec.ch. IEC 60079-7 Edition 5.0 2015-06 INTERNATIONAL STANDARD Explosive atmospheres Part 7: Equipment protection by increased safety e INTERNATIONAL ELECTROTECHNICAL COMMISSION
11、ICS 29.260.20 ISBN 978-2-8322-2710-7 Registered trademark of the International Electrotechnical Commission Warning! Make sure that you obtained this publication from an authorized distributor. 2 IEC 60079-7:2015 IEC 2015 CONTENTS FOREWORD . 8 1 Scope 14 2 Normative references 15 3 Terms and definiti
12、ons 17 4 Constructional requirements 21 4.1 Level of Protection 21 4.2 Electrical connections . 21 4.2.1 General . 21 4.2.2 Field wiring connections 22 4.2.3 Factory connections. 23 4.2.4 External plug and socket connections for field wiring connection . 25 4.3 Clearances . 26 4.4 Creepage distances
13、 26 4.5 Printed wiring boards with conformal coating, Level of Protection “ec” 32 4.6 Solid electrical insulating materials . 33 4.6.1 Specification 33 4.6.2 Long-term thermal stability 33 4.7 Windings . 34 4.7.1 General . 34 4.7.2 Insulated conductors . 34 4.7.3 Winding impregnation 34 4.7.4 Conduc
14、tor dimensions . 34 4.7.5 Sensing elements 35 4.8 Temperature limitations 35 4.8.1 General . 35 4.8.2 Conductors 35 4.8.3 Insulated windings . 36 4.9 Wiring internal to equipment . 36 4.10 Degrees of protection provided by enclosures . 37 4.11 Fasteners . 38 5 Supplementary requirements for specific
15、 electrical equipment . 38 5.1 General . 38 5.2 Electrical machines . 38 5.2.1 General . 38 5.2.2 Degrees of protection provided by electrical machines, Level of Protection “eb” . 39 5.2.3 Degrees of protection provided by electrical machines, Level of Protection “ec” . 39 5.2.4 Connection facilitie
16、s for external conductors 39 5.2.5 Internal fans 39 5.2.6 Minimum air gap 39 5.2.7 Rotating electrical machines with cage rotors 40 5.2.8 Limiting temperature 42 5.2.9 Machines with permanent magnet rotors 45 5.2.10 Stator winding insulation system 45 5.2.11 Supplemental winding requirements Level o
17、f Protection “eb” . 46 IEC 60079-7:2015 IEC 2015 3 5.2.12 Bearing seals and shaft seals 46 5.2.13 Neutral point connections 47 5.3 Luminaires, hand lights, or caplights . 47 5.3.1 General . 47 5.3.2 Light source . 48 5.3.3 Minimum distance between lamp and protective cover . 49 5.3.4 Electrical spac
18、ings . 49 5.3.5 Lampholders and lamp caps 50 5.3.6 Auxiliaries for Luminaires in Level of Protection “ec” 53 5.3.7 Surface temperatures 54 5.3.8 Limiting temperatures 55 5.3.9 Luminaires for tubular fluorescent bi-pin lamps 55 5.3.10 Tests for resistance to impact 56 5.4 Analog measuring instruments
19、 and instrument transformers . 56 5.4.1 General . 56 5.4.2 Limiting temperature 56 5.4.3 Short-circuit currents . 56 5.4.4 Short time thermal current . 57 5.4.5 Measuring instruments supplied by current transformers . 57 5.4.6 Moving coils 57 5.4.7 External secondary circuits 57 5.5 Transformers oth
20、er than instrument transformers 57 5.6 Supplementary requirements for equipment incorporating cells and batteries 58 5.6.1 Type of cells and batteries . 58 5.6.2 Requirements for cells and batteries 25 Ah 59 5.6.3 Requirements for valve-regulated or vented cells or batteries 25 Ah 62 5.6.4 Charging
21、of cells and batteries 65 5.7 General purpose connection and junction boxes . 66 5.8 Resistance heating equipment (other than trace heating systems) 66 5.8.1 General . 66 5.8.2 Heating resistors . 66 5.8.3 Temperature coefficient . 67 5.8.4 Insulating material . 67 5.8.5 Cold-start current . 67 5.8.
22、6 Electrical safety device 67 5.8.7 Electrically conductive covering . 67 5.8.8 Exclusion of explosive atmosphere 68 5.8.9 Conductor cross-section 68 5.8.10 Limiting temperature 68 5.8.11 Safety device . 68 5.9 Supplementary requirements for fuses 69 5.9.1 General . 69 5.9.2 Temperature class of equ
23、ipment 70 5.9.3 Fuse mounting . 70 5.9.4 Fuse enclosures 70 5.9.5 Replacement fuse identification . 70 5.10 Other electrical equipment 70 6 Type verifications and type tests 70 6.1 Dielectric strength . 70 4 IEC 60079-7:2015 IEC 2015 6.2 Rotating electrical machines . 71 6.2.1 Determination of start
24、ing current ratio I A / I Nand the time t E. 71 6.2.2 Mounting of machine for test 71 6.2.3 Additional tests for machines . 71 6.2.4 Overspeed test of cemented magnets 73 6.3 Luminaires 73 6.3.1 Battery operated luminaires . 73 6.3.2 Impact and drop tests 73 6.3.3 Mechanical tests for screw lamphold
25、ers other than E10 . 74 6.3.4 Abnormal operation of luminaires 75 6.3.5 Sulphur dioxide test for Level of Protection “eb” for the connection of bi- pin lamp caps to lampholders 76 6.3.6 Vibration test for Level of Protection “eb” for luminaires with bi-pin lamps 77 6.3.7 Test for wiring of luminaire
26、s subject to high-voltage impulses from ignitors 78 6.3.8 Tests for electronic starters for tubular fluorescent lamps and for ignitors in Level of Protection “ec” for discharge lamps 78 6.3.9 Test for starter holders for luminaires in Level of Protection “ec” . 79 6.4 Measuring instruments and instr
27、ument transformers . 79 6.5 Transformers other than instrument transformers 80 6.6 Verification and tests for cells and batteries of Level of Protection “eb” . 80 6.6.1 General . 80 6.6.2 Insulation resistance 80 6.6.3 Mechanical shock test . 80 6.6.4 Test for ventilation of Level of Protection “eb”
28、 battery container . 81 6.7 Verification and tests for cells and batteries of Level of Protection “ec” . 82 6.7.1 General . 82 6.7.2 Insulation resistance 82 6.7.3 Mechanical shock test . 82 6.7.4 Test for ventilation of Level of Protection “ec” battery container . 82 6.8 General purpose connection
29、and junction boxes . 83 6.8.1 General . 83 6.8.2 Maximum dissipated power method . 83 6.8.3 Defined arrangement method . 83 6.9 Resistance heating equipment 83 6.10 Terminal insulating material tests 84 7 Routine verifications and routine tests . 85 7.1 Dielectric tests 85 7.2 Dielectric tests for b
30、atteries 86 7.3 Inter-turn overvoltage tests . 86 8 Ex Component certificates . 86 8.1 General . 86 8.2 Terminals 86 9 Marking and instructions 87 9.1 General marking . 87 9.2 Ex Component enclosures 88 9.3 Instructions for use . 88 9.3.1 Battery operated equipment . 88 IEC 60079-7:2015 IEC 2015 5 9
31、.3.2 Terminals 88 9.3.3 Luminaires . 88 9.3.4 Machines . 89 9.4 Warning markings . 89 10 Documentation 90 Annex A (normative) Temperature determination of electrical machines Methods of test and of calculation 91 A.1 General . 91 A.2 Determination of maximum service temperatures 91 A.2.1 Rotor tempe
32、rature normal operation . 91 A.2.2 Winding temperature normal operation . 91 A.3 Determination of maximum surface temperatures 92 A.3.1 General . 92 A.3.2 Locked rotor tests 92 A.4 Optional calculation of maximum surface temperature 93 A.4.1 General . 93 A.4.2 Rotor temperature . 93 A.4.3 Stator tem
33、perature . 93 A.5 Determination of t Etime . 93 A.6 Arduous starting conditions . 94 A.7 Motors operated with a converter 94 Annex B (normative) Type tests for specific forms of resistance heating devices or resistance heating units (other than trace heater) 95 B.1 Resistance heating devices subject
34、ed to mechanical stresses 95 B.2 Resistance heating devices or units intended for immersion 95 B.3 Resistance heating devices or units having hygroscopic insulating material 95 B.4 Verification of limiting temperature of resistance heating devices (other than trace heaters) . 95 B.4.1 General . 95 B
35、.4.2 Safety devices . 95 B.4.3 Resistance heating unit of stabilized design. 96 B.4.4 Heating device with temperature self-limiting characteristic . 96 Annex C (informative) Cage motors Thermal protection in service . 97 Annex D (informative) Resistance heating devices and units Additional electrica
36、l protection 98 D.1 Objective 98 D.2 Method of protection . 98 Annex E (informative) Combinations of terminals and conductors for general purpose connection and junction boxes . 99 E.1 General . 99 E.2 Maximum dissipated power method. 99 E.3 Defined arrangement method 99 Annex F (normative) Dimensio
37、ns of copper conductors 102 Annex G (normative) Test procedure for T5 (only 8 W),T8, T10 and T12 lamps 103 G.1 Asymmetric pulse test . 103 G.1.1 General . 103 G.1.2 Test procedure 103 G.2 Asymmetric power test 104 G.2.1 General . 104 6 IEC 60079-7:2015 IEC 2015 G.2.2 Test procedure 105 Annex H (norm
38、ative) Alternative separation distances for Level of Protection “ec” equipment under controlled environments 108 H.1 General . 108 H.2 Specific Conditions of Use 108 H.3 Control of pollution access 109 H.4 Voltage limitation 109 H.5 Control of overvoltages and transient protection . 109 H.6 Alternat
39、ive separation distances . 109 Annex I (informative) Application, installation, and testing considerations for Level of Protection “ec” asynchronous machines. 111 I.1 Surface temperature . 111 I.2 Starting . 111 I.3 Rated voltage and surface discharges 112 Annex J (informative) Luminaires incorporat
40、ing LEDs 113 J.1 LEDs for EPL Gb 113 J.2 LEDs for EPL Gc . 113 Bibliography 114 Figure 1 Determination of creepage distances and clearances . 32 Figure 2 Minimum values of the time t E(in seconds) of motors in relation to the starting current ratio I A /I N43 Figure 3 Arrangement for the luminaire v
41、ibration test . 77 Figure A.1 Diagram illustrating the determination of time t E. 94 Figure E.1 Example of defined terminal/conductor arrangement table 101 Figure G.1 Asymmetric pulse test circuit 104 Figure G.2 Asymmetric power detection circuit . 106 Figure G.3 Flow Chart Asymmetric power Test for
42、 T8, T10, T12 and T5 (8 W lamps) 107 Table 1 Tracking resistance of insulating materials 27 Table 2 Minimum Creepage distances, clearances and separations . 28 Table 3 Conditions for the determination of maximum surface temperature 35 Table 4 Maximum temperatures for insulated windings 36 Table 5 Po
43、tential air gap sparking risk assessment for cage rotor ignition risk factors . 42 Table 6 Stator insulation system tests of Level of Protection “ec” machines . 46 Table 7 Assumed voltage of neutral points . 47 Table 8 Minimum distance between lamp and protective cover 49 Table 9 Creepage distances
44、and clearances at peak values of pulse voltages greater than 1,5 kV . 50 Table 10 Creepage distances and clearances for screw lampholder and lamp cap . 51 Table 11 Resistance to the effect of short-circuit currents 57 Table 12 Types and use of cells and batteries . 59 Table 13 Explosion test mixture
45、s . 72 Table 14 Tests for resistance to impact 74 Table 15 Insertion torque and minimum removal torque . 74 IEC 60079-7:2015 IEC 2015 7 Table 16 Power dissipation of cathodes of lamps supplied by electronic ballasts . 76 Table 17 Value for pull-out tests 85 Table 18 Creepage distances and clearances
46、 for screw lamp caps 89 Table 19 Text of warning markings. 89 Table F.1 Standard cross-sections of copper conductors . 102 Table H.1 Alternative separation distances for equipment under controlled environments 110 8 IEC 60079-7:2015 IEC 2015 INTERNATIONAL ELECTROTECHNICAL COMMISSION _ EXPLOSIVE ATMO
47、SPHERES Part 7: Equipment protection by increased safety e FOREWORD 1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international co-o
48、peration on all questions concerning standardization in the electrical and electronic fields. To this end and in addition to other activities, IEC publishes International Standards, Technical Specifications, Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to
49、 as “IEC Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested in the subject dealt with may participate in this preparatory work. International, governmental and non- governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely with the International Organization for Standardization (ISO) in accordance with conditions determined by
