IEC 60079-14:2024
(Main)Explosive atmospheres - Part 14: Electrical installation design, selection and installation of equipment, including initial inspection
Explosive atmospheres - Part 14: Electrical installation design, selection and installation of equipment, including initial inspection
IEC 60079:2024 contains the specific requirements for the design of electrical systems, selection, installation and the required initial inspection of electrical installations of Ex Equipment in, or associated with, explosive atmospheres including requirements for documentation and personnel competency.
These requirements are in addition to the requirements for installations in non-hazardous areas.
This document applies to all electrical Ex Equipment including fixed, transportable, portable and personal, and installations, permanent or temporary.
This document does not apply to:
• electrical installations in mines susceptible to firedamp;
• inherently explosive situations and dust from explosives or pyrophoric substances (for example explosives manufacturing and processing);
• rooms used for medical purposes;
• electrical installations in areas where the hazard is due to flammable mist; and
• installation of non-electrical Ex Equipment (unless being part of an equipment assembly according IEC TS 60079-46).
No account is taken in this document of the toxic hazards that are associated with flammable gases, liquids and dusts in concentrations that are usually very much less than the lower flammable limit. In locations where personnel could be exposed to potentially toxic concentrations of flammable material, appropriate precautions are necessary. Such precautions are outside the scope of this document.
This sixth edition cancels and replaces the fifth edition published in 2013. This edition constitutes a technical revision. Edition 6 is a major restructure and introduces a number of technical changes from the previous edition (2013), see Table 1 of the foreword for detailed information.
Atmosphères explosives – Partie 14: Conception des installations électriques, sélection et installation des appareils, comprenant l’inspection initiale
IEC 60079-14:2024 contient les exigences spécifiques relatives à la conception de systèmes électriques, à la sélection, à l’installation et à l’inspection initiale exigée des installations électriques des appareils Ex électriques situés dans des atmosphères explosives, ou associées à celles-ci, comprenant les exigences relatives à la documentation et à la compétence du personnel.
Ces exigences complètent celles relatives aux installations dans les emplacements non dangereux.
Le présent document s’applique à tout appareil Ex électrique, comprenant les appareils fixes, transportables, portables, et personnels, et aux installations, permanentes ou temporaires.
Le présent document ne s’applique pas:
• aux installations électriques situées dans des mines grisouteuses;
• aux situations intrinsèquement explosives et aux poussières issues de substances explosives ou pyrophoriques (la fabrication et le traitement d’explosifs, par exemple);
• aux salles utilisées à des fins médicales;
• aux installations électriques situées dans des emplacements où le danger provient d’un brouillard inflammable; et
• à l’installation d’appareils Ex non électriques (sauf s’ils font partie d’un assemblage d’appareils conformément à l’IEC TS 60079-46).
Le présent document ne tient pas compte des dangers toxiques associés aux gaz, liquides et poussières inflammables présents dans des concentrations habituellement bien inférieures à la limite inférieure d’inflammabilité. Sur les sites où le personnel est susceptible d’être exposé à des concentrations potentiellement toxiques de matières inflammables, des précautions appropriées sont nécessaires. Ces précautions ne relèvent pas du domaine d’application du présent document.
Cette sixième édition annule et remplace la cinquième édition parue en 2013. Cette édition constitue une révision technique.
La 6e édition constitue une restructuration majeure et introduit plusieurs modifications techniques par rapport à l’édition précédente (2013). Le Tableau 1, voir AVANT-PROPOS "Tableau des modifications majeures", est fourni afin de mettre en avant les modifications techniques ainsi que les principales modifications rédactionnelles par rapport à l’édition précédente.
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Standards Content (Sample)
IEC 60079-14 ®
Edition 6.0 2024-08
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Explosive atmospheres –
Part 14: Electrical installation design, selection and installation of equipment,
including initial inspection
Atmosphères explosives –
Partie 14: Conception des installations électriques, sélection et installation des
appareils, comprenant l’inspection initiale
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IEC 60079-14 ®
Edition 6.0 2024-08
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Explosive atmospheres –
Part 14: Electrical installation design, selection and installation of equipment,
including initial inspection
Atmosphères explosives –
Partie 14: Conception des installations électriques, sélection et installation des
appareils, comprenant l’inspection initiale
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 29.260.20 ISBN 978-2-8322-9300-3
– 2 – IEC 60079-14:2024 © IEC 2024
CONTENTS
FOREWORD . 10
INTRODUCTION . 16
1 Scope . 19
2 Normative references . 20
3 Terms and definitions . 21
3.1 General . 21
3.2 Hazardous areas . 22
3.3 Flameproof enclosure . 24
3.4 Increased safety . 24
3.5 Intrinsic safety . 25
3.6 Intrinsic safety parameters . 26
3.7 Pressurization . 26
3.8 Type of Protection "n" . 26
3.9 Type of Protection "o" . 27
3.10 Type of Protection "q" . 27
3.11 Type of Protection "m" . 27
3.12 Type of Protection "t" . 27
3.13 Electrical supply systems . 27
3.14 Equipment . 28
3.16 Cable(s) . 28
4 General . 30
4.1 General requirements . 30
4.1.1 Zones and Equipment Protection Levels . 30
4.1.2 Requirements for all Ex Equipment . 31
4.1.3 Electrical ratings . 31
4.1.4 Conditions of control for exceptional circumstances . 31
4.2 Conditions of Use . 32
4.2.1 General . 32
4.2.2 Specific Conditions of Use . 32
4.2.3 Use of Ex Components . 32
4.3 Ignition sources that have an influence on the installation . 33
4.3.1 General . 33
4.3.2 Static electricity . 33
4.3.3 Optical radiation . 33
4.3.4 Lightning protection . 33
4.3.5 Radio frequency received and transmitted in hazardous areas . 33
4.3.6 RFID tags . 34
5 Documentation . 34
5.1 General . 34
5.2 Site information . 35
5.3 Ex Equipment information . 35
5.4 Installation information . 35
5.5 Personnel competency . 36
6 Design . 36
6.1 General . 36
6.2 Protection from dangerous (incendive) sparking . 36
6.2.1 Equipment (other than Ex Equipment) above hazardous areas . 36
6.2.2 Wiring systems traversing a hazardous area . 37
6.2.3 Construction materials . 37
6.2.4 Danger from live parts . 37
6.2.5 Danger from exposed and extraneous-conductive-parts . 38
6.2.6 Protective equipotential bonding . 39
6.2.7 Cathodically protected metallic parts . 40
6.3 Electrical protection . 41
6.4 Emergency stop . 41
6.5 Electrical isolation . 41
6.6 Cables . 42
6.6.1 External surface temperature . 42
6.6.2 Cables subjected to thermal insulation . 42
6.6.3 Overhead wiring . 42
6.7 Electrical machines . 42
6.7.1 General . 42
6.7.2 Electrical machines with Type of Protection "d" – Flameproof
enclosures, "p" – Pressurized enclosures and "t" – Protection by
enclosures . 43
6.7.3 Electrical machines with Level of Protection "eb" – Increased safety . 44
6.7.4 Electrical machines with Level of Protection "ec" and Type of Protection
"nA" . 46
6.7.5 Switching electrical machines above 1 kV AC . 47
6.7.6 Prevention of falling bodies . 48
6.8 Electric heating systems . 48
6.8.1 General . 48
6.8.2 Earth fault protection . 48
6.8.3 Limiting temperature . 49
6.8.4 Temperature safety device . 49
6.9 Plugs, socket outlets and couplers . 50
6.9.1 Specific requirements for explosive dust atmospheres . 50
6.9.2 Location . 50
6.10 Cells and batteries . 51
6.10.1 Charging of secondary cells and batteries . 51
6.10.2 Ventilation . 51
6.11 Gas detection systems . 51
6.12 Type of Protection "d" – Flameproof enclosures . 51
6.13 Type of Protection "e" – Increased safety . 51
6.13.1 Maximum dissipated power of junction boxes . 51
6.13.2 Maximum number of conductors . 52
6.14 Type of Protection "i" – Intrinsic safety . 53
6.14.1 General . 53
6.14.2 Cables . 54
6.14.3 Verification of intrinsically safe circuits . 54
6.14.4 Earthing of conducting screens . 56
6.14.5 Cable armour bonding . 57
6.14.6 Marking of cables . 57
6.14.7 Cables carrying more than one intrinsically safe circuit . 58
6.14.8 Types of cables carrying more than one intrinsically safe circuit and
applicable fault considerations . 58
– 4 – IEC 60079-14:2024 © IEC 2024
6.14.9 Earthing of intrinsically safe circuits . 58
6.14.10 Installations to meet the requirements of EPL Ga or EPL Da . 60
6.14.11 Simple apparatus . 61
6.14.12 Junction boxes . 62
6.14.13 Plugs and sockets used for external connections . 63
6.14.14 Special application: Combining intrinsically safe and non-intrinsically
safe circuits . 63
6.15 Type of Protection "m" – Encapsulation . 63
6.16 Type of Protection "n" . 63
6.16.1 General . 63
6.16.2 Type of Protection "nR" . 64
6.17 Type of Protection "o"– Liquid immersion (former Oil immersion) . 64
6.18 Type of Protection "p" . 64
6.18.1 General . 64
6.18.2 Ducting . 65
6.18.3 Action to be taken on failure of pressurization . 65
6.19 Pressurized rooms and artificially ventilated rooms . 69
6.20 Analyser houses . 69
6.21 Type of Protection "q" – Powder filling . 69
7 Selection . 69
7.1 General . 69
7.2 Assurance of conformity of Ex Equipment . 69
7.2.1 Ex Equipment based on IEC standards . 69
7.2.2 Ex Equipment not based on IEC standards . 69
7.2.3 Selection of used or repaired Ex Equipment . 70
7.3 Selection of Ex Equipment . 70
7.3.1 Information requirements . 70
7.3.2 External influences . 70
7.3.3 Selection of radiating equipment . 71
7.3.4 Selection of ultrasonic equipment . 72
7.3.5 Selection for pollution degree . 73
7.3.6 Selection for specific process hazards . 73
7.3.7 Selection of Ex Equipment according to EPLs . 74
7.3.8 Selection according to equipment grouping . 76
7.3.9 Selection according to the ignition temperature of the gas, vapour or
dust . 77
7.3.10 Selection according to the temperature range . 80
7.4 Selection of cables . 80
7.4.1 General . 80
7.4.2 Wiring systems for installation in areas requiring EPL Ga or EPL Da . 81
7.4.3 Cables for direct entries into flameproof enclosures . 81
7.4.4 Cables for direct entries into restricted breathing enclosures . 81
7.4.5 Resistance to flame propagation or flame spread . 81
7.4.6 UV or solar radiation . 81
7.4.7 Non-flexible cables for fixed equipment . 81
7.4.8 Flexible cables for fixed and transportable equipment (excluding
intrinsic safety circuits) . 81
7.4.9 Flexible cables for use for portable equipment . 82
7.4.10 Cables for intrinsic safety circuits . 82
7.4.11 Single insulated wires (excluding intrinsically safe circuits) . 82
7.4.12 Aluminium conductors. 82
7.5 Selection of entry devices and other fittings . 83
7.5.1 General . 83
7.5.2 Cable entry devices . 83
7.5.3 Adapters and Blanking Elements . 84
7.5.4 Breathing and draining devices . 84
7.5.5 Entry devices for fibre optic cables . 85
7.5.6 Other entry devices . 85
7.5.7 Cable entry device for Type of Protection "d" . 85
7.5.8 Cable entry device for Type of Protection "nR" . 86
7.6 Conduits . 87
7.6.1 Group II . 87
7.6.2 Group III . 87
7.7 Luminaires and lamps . 88
7.7.1 Luminaires . 88
7.7.2 Lamps . 88
7.8 Rotating electrical machines . 88
8 Installation of equipment . 88
8.1 General . 88
8.2 Cables and wiring systems . 88
8.2.1 Avoidance of damage . 88
8.2.2 Equipotential bonding connections . 89
8.2.3 Terminations . 89
8.2.4 Penetrations in structures . 90
8.2.5 Passage and collection of flammables . 90
8.2.6 Group III ‒ Accumulation of dust . 90
8.2.7 Jointing . 90
8.3 Entry devices and other fittings . 90
8.3.1 General . 90
8.3.2 Cable entry devices . 91
8.3.3 Additional entries . 93
8.3.4 Unused openings . 93
8.4 Conduit systems . 93
8.4.1 General . 93
8.4.2 Group II . 94
8.4.3 Group III . 94
8.4.4 Additional requirements for flameproof sealing devices for conduit . 95
8.5 Electrical heating systems. 95
8.5.1 General . 95
8.5.2 Trace heating system . 95
8.6 Protective coating of Ex Equipment . 95
8.7 Type of Protection "d" – Flameproof enclosures . 96
8.7.1 General . 96
8.7.2 Solid obstacles . 96
8.7.3 Protection of flamepaths . 96
8.8 Types of Protection "e" and "nA" . 97
8.8.1 Conductor terminations . 97
– 6 – IEC 60079-14:2024 © IEC 2024
8.8.2 Combinations of terminals and conductors for general connection and
junction boxes . 97
8.9 Types of Protection "i" – Intrinsic safety . 97
8.9.1 Earthing of conducting screens . 97
8.9.2 Cable armour bonding . 97
8.9.3 Installation of cables and wiring . 98
8.10 Type of Protection "nR" . 99
8.11 Type of Protection "o"– Liquid immersion (formerly Oil immersion) . 99
9 Initial inspection . 99
Annex A (normative) Knowledge, skills and competencies of designers, electricians
and technicians . 100
A.1 Scope . 100
A.2 Knowledge and skills . 100
A.2.1 Designers . 100
A.2.2 Electricians and technicians. 100
A.3 Competencies . 101
A.3.1 General . 101
A.3.2 Designers . 101
A.3.3 Electricians and technicians. 101
A.4 Assessment . 101
Annex B (informative) Safe work procedure guidelines for explosive gas atmospheres . 102
Annex C (normative) Pressure test procedure for cables into Ex "d" enclosures . 103
C.1 General . 103
C.2 Test apparatus . 103
C.3 Test method . 103
C.4 Test report . 104
Annex D (normative) Potential stator winding discharge hazard assessment – Ignition
risk factors . 106
Annex E (normative) Verification of intrinsically safe circuits with more than one
intrinsically safe power source with linear current/voltage characteristics . 107
E.1 General . 107
E.2 Intrinsic safety with Level of Protection "ib" . 107
E.3 Intrinsic safety with Level of Protection "ic" . 107
Annex F (informative) Methods of determining the maximum system voltages and
currents in intrinsically safe circuits with more than one intrinsically safe power source
with linear current and voltage characteristics . 108
F.1 Intrinsically safe circuits with linear current and voltage characteristics . 108
F.2 Intrinsically safe circuits with non-linear current or voltage characteristics . 109
Annex G (informative) Determination of intrinsic safety cable parameters . 110
G.1 Measurements . 110
G.2 Cables carrying more than one intrinsically safe circuit . 110
G.2.1 General . 110
G.2.2 Type A cables . 110
G.2.3 Type B cables . 111
G.2.4 Type C cables . 111
G.3 FISCO . 111
Annex H (informative) Hybrid mixtures . 112
H.1 General . 112
H.2 Concentration limits . 112
H.3 Electrostatic hazard . 112
H.4 Energy/temperature limits . 112
H.5 Selection of equipment . 112
H.6 Use of flameproof equipment . 112
H.7 Installation requirements . 112
Annex I (informative) Transportable, portable and personal equipment . 113
I.1 General . 113
I.2 Transportable and portable equipment . 113
I.3 Personal equipment . 114
Annex J (informative) Electrical machines operated from converters . 115
J.1 General . 115
J.2 Earthing, bonding and cabling . 116
J.2.1 Objectives of earthing . 116
J.2.2 Bonding of machines . 116
J.2.3 Machine power cables . 116
J.2.4 Cable terminations . 118
J.2.5 Interruption of the shielded machine supply line . 119
Annex K (informative) Surge protection of an intrinsically safe circuit . 120
K.1 General . 120
K.2 Installation to be protected . 120
K.3 Lightning induced surges . 120
K.4 Preventive measures . 120
K.5 Supporting documentation . 121
K.6 Further protection . 121
Annex L (informative) Adverse environmental conditions . 122
L.1 Climate classifications . 122
L.2 Cables and cable entry devices. 122
L.3 Seals and sealing materials . 122
L.4 Storage and transportation . 122
L.5 Low temperatures . 122
L.5.1 General . 122
L.5.2 Electrical machines . 123
L.6 High humidity . 123
L.7 Solar radiation . 123
L.7.1 General . 123
L.7.2 Equipment protection . 124
L.7.3 Cables and cable entry devices . 124
L.8 Atmospheres containing salt and chlorides . 124
L.9 Snow conditions . 124
L.10 Icing and winterization . 125
L.11 Rapid cooling . 125
Annex M (informative) Guidance on the different duty types S1 to S10 of electrical
machines . 126
Annex N (normative) High voltage installations with rated voltage up to 245 kV . 127
Annex O (informative) Inspection tables for initial inspections (from IEC 60079-17) . 128
Annex P (informative) Minimum degree of protection (IP Code) in accordance to Type
of Protection . 135
Annex Q (normative) Additional requirements for simple apparatus. 136
– 8 – IEC 60079-14:2024 © IEC 2024
Q.1 Temperature classification . 136
Q.1.1 Group II . 136
Q.1.2 Group III . 137
Q.2 Isolation and separation . 137
Q.3 Enclosures and cable entry devices . 137
Q.4 Assessment and documentation . 138
Bibliography . 141
Figure 1 – Correlation between the maximum permissible surface temperature and
thickness of dust layers . 79
Figure 2 – Selection of cable entry devices . 86
Figure C.1 – Example of a low pressure test arrangement . 103
Figure F.1 – Series connection – Summation of voltage . 108
Figure F.2 – Parallel connection – Summation of currents . 109
Figure F.3 – Series and parallel connections – Summations of voltages and
summations of currents . 109
Figure J.1 – Basic structure of a converter fed drive system . 115
Figure J.2 – Examples of shielded machine cables and connections . 117
Figure J.3 – Cable shield connection at the machine side . 119
Figure K.1 – Surge protection requirements of an instrument loop . 121
Figure Q.1 – Assessment process for simple apparatus . 138
Table 1 – Table of significant changes . 11
Table 2 – Clauses of this document for requirements for special types of equipment . 14
Table 3 – Clauses of this document for additional requirements for Types of Protection . 14
Table 4 – Equipment Protection Levels (EPLs) where only zones are assigned . 30
Table 5 – Radio frequency power thresholds . 33
Table 6 – Radio-frequency energy thresholds . 34
Table 7 – Requirements for the temperature safety devices . 50
Table 8 – Example of defined terminal/conductor arrangement – Maximum number of
wires in relation to the cross-section and the permissible continuous current . 52
Table 9 – Determination of Type of Protection (with no flammable release within the
enclosure) . 64
Table 10 – Use of spark and particle barriers . 65
Table 11 – Summary of protection requirements for enclosures without an internal
source of release . 66
Table 12 – Relationship between EPLs and Types of Protection . 75
Table 13 – Relationship between gas/vapour or dust subdivision and equipment group . 77
Table 14 – Relationship between gas or vapour ignition temperature and temperature
class of Ex Equipment . 78
Table 15 − Selection of cable entry devices, Type of Protection according to the
enclosure Type of Protection . 84
Table 16 – Minimum dista
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