oSIST prEN IEC 60079-7:2026

SLOVENSKI STANDARD
01-april-2026
Eksplozijska okolja - 7. del: Zaščita opreme z izboljšano varnostjo "e"
Explosive atmospheres - Part 7: Equipment protection by increased safety "e"
Explosionsgefährdete Bereiche - Teil 7: Geräteschutz durch erhöhte Sicherheit "e"
Atmosphères explosives - Partie 7: Protection du matériel par sécurité augmentée "e"
Ta slovenski standard je istoveten z: prEN IEC 60079-7:2026
ICS:
29.260.20 Električni aparati za Electrical apparatus for
eksplozivna ozračja explosive atmospheres
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

31/1955/CDV
COMMITTEE DRAFT FOR VOTE (CDV)
PROJECT NUMBER:
IEC 60079-7 ED6
DATE OF CIRCULATION: CLOSING DATE FOR VOTING:
2026-03-06 2026-05-29
SUPERSEDES DOCUMENTS:
31/1938/RR
IEC TC 31 : EQUIPMENT FOR EXPLOSIVE ATMOSPHERES
SECRETARIAT: SECRETARY:
United Kingdom Mr Tom Stack
OF INTEREST TO THE FOLLOWING COMMITTEES: HORIZONTAL FUNCTION(S):

ASPECTS CONCERNED:
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TITLE:
Explosive atmospheres - Part 7: Equipment protection by increased safety "e"

PROPOSED STABILITY DATE: 2029
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IEC CDV 60079-7 © IEC 2026
CONTENTS
Contact . 2
CONTENTS . 3
FOREWORD . 10
INTRODUCTION . 18
1 Scope . 21
2 Normative references . 21
3 Terms and definitions . 24
4 Construction requirements . 28
4.1 Level of Protection . 28
4.2 Electrical connections . 28
4.2.1 General . 28
4.2.2 Field wiring connections . 29
4.2.3 Factory connections . 31
4.2.4 External plug and socket-outlet connections for field wiring connection . 33
4.3 Insulation coordination . 34
4.3.1 Environmental conditions . 34
4.3.2 Clearances . 35
4.3.3 Creepage distances . 36
4.3.4 Separation distances . 38
4.4 Printed circuit boards with coating, Level of Protection "ec" . 43
4.5 Solid electrical insulating materials . 44
4.5.1 General . 44
4.5.2 Specification . 44
4.5.3 Long-term thermal stability . 45
4.6 Windings . 45
4.6.1 General . 45
4.6.2 Insulated conductors . 45
4.6.3 Winding impregnation . 45
4.6.4 Conductor dimensions . 46
4.6.5 Sensing elements . 46
4.7 Limiting temperature . 46
4.7.1 General . 46
4.7.2 Conductors . 47
4.7.3 Insulated windings . 47
4.8 Wiring internal to equipment . 48
4.9 Degree of protection (IP Code) provided by enclosures . 48
4.9.1 General . 48
4.9.2 Drain holes or ventilation openings . 49
4.9.3 Live maintenance - Type of Protection "i" circuits or apparatus . 49
4.10 Fasteners . 49
5 Supplementary requirements for specific electrical equipment . 50
5.1 General . 50
5.2 Electric machines . 50
5.2.1 General . 50
5.2.2 Degrees of protection provided by electric machines, Level of
Protection "eb". 50
IEC CDV 60079-7 © IEC 2026
5.2.3 Degrees of protection provided by electric machines, Level of
Protection "ec" . 50
5.2.4 Connection facilities for external conductors . 51
5.2.5 Internal cooling fans . 51
5.2.6 Minimum acceptable air gap . 51
5.2.7 Rotating electric machines with cage rotors . 52
5.2.8 Determination of limiting temperature . 54
5.2.9 Machines with permanent magnet rotors . 57
5.2.10 Machines with reluctance rotors. 58
5.2.11 Stator winding insulation system . 58
5.2.12 Supplemental winding requirements Level of Protection "eb" . 59
5.2.13 Bearing seals and shaft seals for Level of Protection "eb" . 59
5.2.14 Neutral point connections . 59
5.2.15 Anti-condensation heaters . 60
5.3 Luminaires, hand lights, or caplights . 60
5.3.1 General . 60
5.3.2 Light source . 61
5.3.3 Minimum distance between lamp and protective cover . 62
5.3.4 Electrical spacings . 62
5.3.5 Lampholders and lamp caps . 63
5.3.6 Auxiliaries for Luminaires in Level of Protection "ec" . 66
5.3.7 Surface temperatures . 67
5.3.8 Limiting temperatures . 68
5.3.9 Luminaires for tubular fluorescent bi-pin lamps . 68
5.3.10 Tests for resistance to impact . 69
5.4 Analog measuring instruments and instrument transformers . 69
5.4.1 General . 69
5.4.2 Limiting temperature . 70
5.4.3 Short-circuit currents . 70
5.4.4 Short time thermal current . 70
5.4.5 Measuring instruments supplied by current transformers . 70
5.4.6 Moving coils . 70
5.4.7 External secondary circuits . 70
5.5 Transformers other than instrument transformers . 71
5.6 Supplementary requirements for equipment incorporating cells and batteries . 71
5.6.1 Type of cells and batteries . 71
5.6.2 Requirements for cells and batteries ≤ 25 Ah . 73
5.6.3 Requirements for valve-regulated or vented cells or batteries >25 Ah . 75
5.6.4 Charging of cells and batteries . 79
5.7 Enclosures . 80
5.7.1 General purpose connection and junction boxes . 80
5.9 Low-voltage switchgear and controlgear assemblies . 80
5.10 Resistance heating equipment (other than trace heating systems) . 80
5.10.1 General . 80
5.10.2 Heating resistors . 80
5.10.3 Temperature coefficient . 81
5.10.4 Insulating material . 81
5.10.5 Cold-start current. 81
5.10.6 Electrical safety device . 81
IEC CDV 60079-7 © IEC 2026
5.10.7 Electrically conductive covering . 81
5.10.8 Exclusion of explosive atmosphere . 82
5.10.9 Conductor cross-section . 82
5.10.10 Limiting temperature . 82
5.10.11 Safety device . 82
5.11 Supplementary requirements for fuses . 83
5.11.1 General . 83
5.11.2 Temperature class of equipment . 83
5.11.3 Fuse mounting . 84
5.11.4 Fuse enclosures . 84
5.11.5 Replacement fuse identification . 84
6 Type verifications and type tests . 84
6.1 Dielectric strength . 84
6.2 Rotating electric machines . 85
6.2.1 Determination of starting current ratio I / I and the time t . 85
A N E
6.2.2 Mounting of machine for test . 85
6.2.3 Additional tests for machines . 85
6.2.4 Overspeed test . 86
6.3 Luminaires . 87
6.3.1 Battery operated luminaires . 87
6.3.2 Mechanical tests for screw lampholders other than E10 . 87
6.3.3 Abnormal operation of luminaires . 87
6.3.4 Sulphur dioxide test for Level of Protection "eb" for the connection of bi-
pin lamp caps to lampholders . 89
6.3.5 Vibration test for Level of Protection "eb" for luminaires with bi-pin
lamps . 89
6.3.6 Test for wiring of luminaires subject to high-voltage impulses from
ignitors . 90
6.3.7 Tests for electronic starters and ignitors . 91
6.3.8 Test for starter holders . 92
6.4 Measuring instruments and instrument transformers . 92
6.5 Transformers other than instrument transformers . 93
6.6 Verification and tests for cells and batteries of Level of Protection "eb". 93
6.6.1 General . 93
6.6.2 Insulation resistance . 93
6.6.3 Mechanical shock test . 93
6.6.4 Test for ventilation of Level of Protection "eb" battery container . 94
6.7 Verification and tests for cells and batteries of Level of Protection "ec" . 95
6.7.1 General . 95
6.7.2 Insulation resistance . 95
6.7.3 Mechanical shock test . 95
6.7.4 Test for ventilation of Level of Protection "ec" battery container . 95
6.8 General purpose connection and junction boxes . 95
6.8.1 General . 95
6.8.2 Maximum dissipated power method . 96
6.8.3 Defined arrangement method . 96
6.9 Low-voltage switchgear and controlgear assemblies . 96
6.10 Resistance heating equipment . 96
6.11 Terminal insulating material tests . 97
IEC CDV 60079-7 © IEC 2026
7 Routine verifications and routine tests . 98
7.1 Dielectric tests . 98
7.2 Insulation resistance tests for "eb" batteries. 99
7.3 Inter-turn overvoltage tests . 99
7.4 Thermal assessment of low-voltage switchgear and controlgear assemblies . 99
8 Certificates . 99
8.1 Ex Component Certificates. 99
8.2 Ex Component Certificates - Terminals . 99
8.3 Ex Equipment Certificates . 100
9 Marking . 100
9.1 General . 100
9.2 Enclosures . 101
9.2.1 Ex Component enclosures . 101
9.3 Warning markings . 101
10 Instructions . 102
10.1 General . 102
10.2 Terminals . 102
10.3 Ex Equipment electric machines . 102
10.4 Ex Equipment Luminaires . 102
10.5 Battery operated Ex Equipment . 103
11 Schedule Drawings . 103
Annex A (normative) Temperature determination of electric machines - Methods of
test and of calculation . 104
A.1 General . 104
A.2 Determination of maximum service temperatures . 104
A.2.1 Rotor temperature - normal operation . 104
A.2.2 Winding temperature - normal operation . 104
A.3 Determination of maximum surface temperatures . 105
A.3.1 General . 105
A.3.2 Motors supplied by a converter . 105
A.3.3 Locked rotor tests when powered from a sinusoidal supply . 105
A.4 Optional calculation of maximum surface temperature . 106
A.4.1 General . 106
A.4.2 Rotor temperature . 106
A.4.3 Stator temperature . 106
A.5 Determination of t time . 107
E
A.6 Arduous starting conditions . 107
Annex B (normative) Type tests for specific forms of resistance heating devices or
resistance heating units (other than trace heater) . 108
B.1 Resistance heating devices subjected to mechanical stresses . 108
B.2 Resistance heating devices or units intended for immersion. 108
B.3 Resistance heating devices or units having hygroscopic insulating material . 108
B.4 Verification of limiting temperature of resistance heating devices (other than
trace heaters) . 108
B.4.1 General . 108
B.4.2 Safety devices . 108
B.4.3 Resistance heating unit of stabilized design . 109
B.4.4 Heating device with temperature self-limiting characteristic . 109
IEC CDV 60079-7 © IEC 2026
Annex C (informative) Cage motors - Thermal protection in service . 110
Annex D (informative) Resistance heating devices and units - Additional electrical
protection . 111
D.1 Objective . 111
D.2 Method of protection . 111
Annex E (informative) Combinations of terminals and conductors for general purpose
connection and junction boxes . 112
E.1 General . 112
E.2 Maximum dissipated power method . 112
E.3 Defined arrangement method . 112
Annex F (normative) Dimensions of copper conductors . 114
Annex G (normative) Test procedure for T5 (only 8 W), T8, T10 and T12 lamps . 115
G.1 Asymmetric pulse test . 115
G.1.1 General . 115
G.1.2 Test procedure . 115
G.2 Asymmetric power test . 116
G.2.1 General . 116
G.2.2 Test procedure . 116
Annex H (normative) Alternative separation distances for Level of Protection "ec"
equipment under controlled environments . 120
H.1 General . 120
H.2 Specific Conditions of Use . 120
H.3 Control of pollution access . 121
H.4 Control of overvoltages and transient protection . 121
H.5 Alternative separation distances . 122
Annex I (informative) Application, installation, and testing considerations for Level of
Protection "ec" asynchronous machines . 123
I.1 Surface temperature . 123
I.2 Starting . 123
I.3 Rated voltage and surface discharges . 124
Annex J (informative) Luminaires incorporating LED Packages . 125
J.1 LED Packages for EPL Gb . 125
J.2 LED Packages for EPL Gc . 125
Annex K (normative) Electric machines supplied by a converter - Instructions. 126
Annex L (informative) Guidance on the selection of comparable converters . 127
L.1 Machine temperature rise and operational principles of converters . 127
L.2 Loss components . 127
L.3 Motor voltage limitations due to rectifier supply type . 127
L.3.1 General . 127
L.3.2 Diode rectifiers . 128
L.3.3 Active rectifiers . 128
L.4 Modulation, pulse frequency, and converter topology . 128
L.5 Test conditions . 129
Annex M (normative) Thermal assessment of low-voltage switchgear and controlgear
assemblies . 131
M.1 General . 131
M.2 Practical application of the thermal assessment methods . 131
M.2.1 Verification by testing . 131
IEC CDV 60079-7 © IEC 2026
M.2.2 Verification by comparison . 132
M.2.3 Verification by assessment by calculation (modelling) . 132
Bibliography . 133

Figure 1 – Clearance for Level of Protection "ec" . 36
Figure 2 – Creepage distance for Level of Protection "ec" . 37
Figure 3 – Example 1 - Determination of creepage distances and clearances . 40
Figure 4 – Example 2 - Determination of creepage distances and clearances . 40
Figure 5 – Example 3 - Determination of creepage distances and clearances . 40
Figure 6 – Example 4 - Determination of creepage distances and clearances . 41
Figure 7 – Example 5 - Determination of creepage distances and clearances . 41
Figure 8 – Example 6 - Determination of creepage distances and clearances . 41
Figure 9 – Example 7 - Determination of creepage distances and clearances . 42
Figure 10 – Example 8 - Determination of creepage distances and clearances . 42
Figure 11 – Example 9 - Determination of creepage distances and clearances . 42
Figure 12 – Example 10 - Determination of creepage distances and clearances . 43
Figure 13 – Example 11 - Determination of creepage distances and clearances . 43
Figure 14 – Minimum values of the time t (in seconds) of motors in relation to the
E
starting current ratio I / I . 55
A N
Figure 15 – Arrangement for the luminaire vibration test . 90
Figure A.1 – Diagram illustrating the determination of time t . 107
E
Figure E.1 – Example of defined terminal/conductor arrangement table . 113
Figure G.1 – Asymmetric pulse test circuit . 116
Figure G.2 – Asymmetric power detection circuit . 118
Figure G.3 – Flow Chart - Asymmetric power Test for T8, T10, T12 and T5 (8 W lamps) . 119

Table 1 – Tracking resistance of insulating materials . 36
Table 2 – Minimum Creepage distance, clearance, and distance under coating . 38
Table 3 – Conditions for the determination of maximum surface temperature . 46
Table 4 – Maximum permissible temperatures for insulated windings . 47
Table 5 – Separation in compound-filled cable sealing boxes . 51
Table 6 – Potential air gap sparking hazard assessment for cage rotor ignition factors . 53
Table 7 – Stator insulation system tests of Level of Protection "ec" machines . 58
Table 8 – Assumed voltage of neutral points . 60
Table 9 – Minimum distance between lamp and protective cover . 62
Table 10 – Spacings for pulse voltages greater than 1,5 kV . 63
Table 11 – Creepage distances and clearances for screw lampholder and lamp cap . 64
Table 12 – Resistance to the effect of short-circuit currents . 70
Table 13 – Types and use of cells and batteries . 72
Table 14 – Explosion test mixtures . 86
Table 15 – Insertion torque and minimum removal torque . 87
Table 16 – Power dissipation of cathodes of lamps supplied by electronic control gear . 89
Table 17 – Value for pull-out tests . 97
IEC CDV 60079-7 © IEC 2026
Table 18 – Text of warning markings . 101
Table 19 – Creepage distances and clearances for screw lamp caps . 102
Table F.1 – Standard cross-sections of copper conductors . 114
Table H.1 – Alternative minimum separation distances for equipment under controlled
environments . 122
Table K.1 – Example of specific (type-test) converter parameters . 126
Table L.1 – Modulation method and converter topology comparison . 129

IEC CDV 60079-7 © IEC 2026
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
Explosive atmospheres -
Part 7: Equipment protection by increased safety "e"

FOREWORD
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IEC CDV 60079-7 © IEC 2026
may be obtained from the patent database available at https://patents.iec.ch. IEC shall not be
held responsible for identifying any or all such patent rights.
IEC 60079-7 has been prepared by IEC technical committee 31: Equipment for explosive
atmospheres. It is an International Standard.
This sixth edition cancels and replaces the fifth edition published in 2015. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
Type
Changes Clause/ Minor and Extension Major
Subclause editorial technical
changes changes
"Equipment" replaced by "Ex Equipment" General X

Clarification of documentation to specifically point General X

to Schedule Drawings
Updated RTD to ETD to cover additional devices General X

Changed "Electrical Machines" to "Electric General X

Machines"
"Ballast" replaced by "Control Gear" in Luminaire General X

applications
IEC 60044-6 is replaced by IEC 61869-2 Clause 2 X

IEC 60079-15 is added Clause 2 X

IEC 60947-7-3 is added Clause 2 X

ANSI/UL 746B is added Clause 2 X

ANSI/UL 746E is added Clause 2 X

Battery Definitions are moved to IEC 60079-0 Clause 3 X

Definition for "Fuse" moved to IEC 60079-0 Clause 3 X

Series of "LED related definitions" added along 3.8 (3.8) X

with Notes to Entry
Definition for "LED" added 3.8.1 (3.8.1) X

Definition for "LED module" revised 3.8.2 (3.8.2) X

Definition for "LED Package" revised 3.8.3 (3.8.3) X

Low Voltage Switchgear and Controlgear 3.9 (3.9) X

assemblies definition added
IEC CDV 60079-7 © IEC 2026
Type
Changes Clause/ Minor and Extension Major
Subclause editorial technical
changes changes
Definition for "Rate of temperature rise of the 3.13 (3.13) X

stator" has been added
Pulse Frequency definition added 3.15 (3.15) X

Semiconductor Device definition added 3.16 (3.16) X

"Solid Insulation" definition moved to IEC 60079-0 Clause 3 X

Switching Frequency definition added 3.20 (3.20) X

Revised Definition of Terminal and added 3.21 (3.21) X

indication of domain
"Safety Device" definition moved to IEC 60079-0 Clause 3 X

"Transportable" definition moved to IEC 60079-0 Clause 3 X

Clarification that the arcing and sparking device in 4.1 X

an enclosure must have tool access
No additional requirements for connection of 4.2.1 X

stranded conductors beyond those of the general
industrial requirements
Clarified requirements of contact pressure through 4.2.1 X

insulating materials
Addressed fused terminal blocks per IEC 60947-7- 4.2.2.2 X

Clarified Soldering as a connection method 4.2.3.3, list X

item d)
Clarified the group connections of pluggable 4.2.3.4, list X

connection item c)
Clarified the group connections of pluggable 4.2.3.5 X

connection
Clarified the group connections of pluggable 4.2.3.6 X

connection
Clarification of Terms for Socket Outlet and Inlet 4.2.4 X

Added Field Wiring connections involving Plugs 4.2.4 X

and Socket Outlets
Clarification of Securing requirements and 4.2.4, list X

evaluation item b)
Introduction into Insulation coordination 4.3 C1

Summarized Environmental conditions for 4.3.1 C1

Insulation coordination and provide details and
application of micro- and macro- environments
Clarified requirements for Clearance Distances 4.3.3 C1

Clarified requirements for Creepage Distances 4.3.4 C1

IEC CDV 60079-7 © IEC 2026
Type
Changes Clause/ Minor and Extension Major
Subclause editorial technical
changes changes
Clarified requirements for separation distances 4.3.4 C1

Clarified requirements Separation Distances and 4.4 C1

Coatings for Printed Circuit Boards
Clarified requirements for Solid Insulating materials 4.5 X

Clarified winding wire requirements 4.6.2, list X

item b)
Corrected requirements to align with IEC 60034-1 4.7.3 X

Table 4
Requirements for "ec" moved to IEC 60079-0 4.9.1 X
...