EN IEC 60079-11:2024/prA1:2026

• Status: Not Published
• Publication Date: 01-Feb-2028
• ICS: 29.260.20 - Electrical apparatus for explosive atmospheres
• Technical Committee: CLC/TC 31 - Electrical apparatus for explosive atmospheres - General requirements
• Current Stage: 4020 - Enquiry circulated - Enquiry
• Start Date: 28-Aug-2026
• Due Date: 05-Dec-2025
• Completion Date: 28-Aug-2026
• Directive: 2014/34/EU - Directive 2014/34/EU Of The European Parliament And Of The Council of 26 February 2014 on the harmonisation of the laws of the Member States relating to equipment and protective systems intended for use in potentially explosive atmospheres (recast)
• Mandate: M/596 - [C(2023)4798] Commission Implementing Decision of 20.7.2023 on a standardisation request as regards equipment and protective systems intended for use in potentially explosive atmospheres in support of Directive 2014/34/EU (ATEX) of the European Parliament and of the Council
• Ref Project: SIST EN IEC 60079-11:2025/oprA1:2026 - Amendment 1 - Explosive atmospheres - Part 11: Equipment protection by intrinsic safety "i"

• Amends: EN IEC 60079-11:2024 - Explosive atmospheres - Part 11: Equipment protection by intrinsic safety "i"
• Effective Date: 13-May-2025

EN IEC 60079-11:2024/prA1:2026 is a CENELEC amendment to IEC 60079-11, Part 11 of the Explosive atmospheres series, on equipment protection by intrinsic safety “i”. It updates the technical rules for designing, assessing, and testing intrinsically safe apparatus intended for use in explosive atmospheres. Engineers, manufacturers, test laboratories, and certification bodies use it when they need to control ignition risk by limiting electrical and thermal energy.

What does EN IEC 60079-11:2024/prA1:2026 specify?

EN IEC 60079-11:2024/prA1:2026 specifies amendments to the requirements for intrinsically safe equipment protection “i” in explosive atmospheres. In practice, it revises how designers treat thermal ignition, separations, encapsulation, semiconductors, programmable components, PPTC devices, spark testing, PCB coatings, and transient-energy assessment.

The amendment is organized around the technical clauses it changes, especially Clauses 5, 6, 7 and 9, plus Annex D and Annex G. These parts matter because they are the places where the document turns intrinsic-safety principles into component rules, fault assumptions, test methods, and assessment procedures.

Annex	What it covers
D	Analysis and measurement of transient output energy for controlled semiconductor current or voltage limitation
G	Assessment procedure and curves for power sources with rectangular or linear output characteristics

What are the key requirements of EN IEC 60079-11:2024/prA1:2026?

Thermal ignition and wiring

Clause 5.4.1 clarifies how sealed components are treated in thermal ignition analysis. For sealed parts other than fuses, the relevant surface is taken as the package surface, which matters because the analysis can be based on the exposed outer surface instead of assuming the atmosphere reaches the interior.

Clause 5.4.3 gives the method for the maximum permissible current in wiring within intrinsically safe apparatus for Group I and Group II. Designers must use the table for copper wire or calculate the value from the wire material data, melting temperature, ambient temperature, and threshold temperature. In practice, this is what bounds self-heating so the wire stays below the ignition-related temperature limit.

Separation and enclosure protection

Clauses 6.2.2 and 6.2.3 link intrinsic safety to enclosure protection by the IP Code in IEC 60529. Where apparatus relies on the separation requirements of Table 7, the enclosure must provide at least IP2X. Where it relies on the reduced separation requirements of Tables 8 or 9, the enclosure must provide at least IP54 and meet the related separation protection requirements. That means enclosure design and component spacing both matter, not just the circuit itself.

Clause 6.5.1 reorganizes the separation rules and adds detail for Levels of Protection “ia”, “ib” and “ic”. For “ia” and “ib”, internal separations within components can count in more cases than for “ic”, but only under the stated conditions. The practical effect is that component layout, footprint design, and fault analysis must be checked together, including movement of conductors and manufacturing tolerance.

Clause 6.5.1.2 and 6.5.1.3 explain when the insulation of prefabricated components can be considered part of the separation. The rules distinguish between “ia”/“ib” and “ic”, and they place limits on when solder pads and tracks can be treated as not reducing separation. This matters for PCB design because a component body or footprint cannot be assumed to provide isolation unless the clause conditions are met.

Encapsulation and component rating

Clause 6.6.1 tightens the encapsulation requirements. For fuses, the compound operating temperature, or COT, has to suit the ambient range. For other components, normal operation must keep the interface temperature within the compound rating, and abnormal conditions may only exceed it if the compound is not damaged in a way that could compromise intrinsic safety. In practice, compound cracks, shrinkage, swelling, flaking, softening, or exposed parts are all assessment concerns.

Clause 7.4.2 updates the use of resistive elements for current limitation, including fuses, lamp filaments in handlights or caplights, and infra-red sources in gas detectors. The resistance value used for assessment is the cold resistance at minimum service temperature. That means component selection must match the actual operating context, not a room-temperature nominal value.

Semiconductors, programmable components, and PPTC devices

Clause 7.7.2 sets the rating and failure-mode treatment for semiconductors. It distinguishes “ia” and “ib” from “ic” by the safety factor applied to ratings and by how faults are counted. For designers, this is a fault-assumption rule: the circuit has to stay safe when semiconductor failure modes are considered at the level required by the protection concept.

Clause 7.7.6 lists shunt assembly constructions that are treated as infallible for Level of Protection “ia” when they meet the stated conditions. The clause also limits how countable faults are applied within and between the limiting circuits. This is important for redundant voltage-limiting networks, because the layout, tracks, vias, and interconnections are all part of the safety case.

Clause 7.7.8 states how programmable components are treated. For “ia” and “ib”, their failure is a non-countable fault. For “ic”, they may set control levels and form part of thermal-ignition control loops, but they shall not be relied on to respond to spark-ignition risk events. That means firmware-controlled circuits need clear boundaries on what software may and may not decide.

Clause 7.16.3 covers PPTC devices used to limit current. The thermal assessment is based on maximum available power, not on trip temperature, and the external connections must still meet the separation rules. In practice, a PPTC device is not treated as a simple thermal fuse; its self-heating and fault behavior have to be assessed explicitly.

Tests and transient-energy assessment

Clause 9.1.2 updates the spark test apparatus check before each test series. The apparatus sensitivity has to be verified with the specified circuit and coil arrangement, and an over-sensitive setup invalidates the test. This matters because the ignition test itself depends on using a repeatable and controlled test rig.

Clause 9.8 aligns PCB coating tests with IEC 60664-3 and distinguishes type 1 protection from type 2 protection. The clause also clarifies what kinds of printed circuit board samples may be used. For manufacturers, that affects how coating qualification samples are chosen and how representative they must be of production.

Clause 9.14.1.4 adds further testing for cell or supercapacitor surface temperature after earlier tests. The extra samples are tested under the conditions that produced the maximum surface temperature, so the worst-case thermal behavior has to be captured.

Annex D defines the analysis and measurements for transient output energy from controlled semiconductor limitation. Annex G sets the assessment procedure for output characteristics, including enveloping curves and the limits to use for rectangular and linear source assessments. Together, they give the method for showing that transient energy remains low enough for intrinsic safety.

What terms does EN IEC 60079-11:2024/prA1:2026 define?

• Intrinsic safety “i” - A protection method that limits electrical and thermal energy so ignition is not likely in an explosive atmosphere.
• Level of Protection “ia” - The most conservative intrinsic-safety level used in this document, with stricter fault assumptions.
• Level of Protection “ib” - An intrinsic-safety level with fault assumptions between “ia” and “ic”.
• Level of Protection “ic” - An intrinsic-safety level with fewer fault assumptions and different separation treatment.
• COT - The compound operating temperature used to judge whether an encapsulating compound remains suitable.
• PPTC device - A polymer positive temperature coefficient device used here to limit current by self-heating.
• Programmable component - A microcontroller, microprocessor, programmable logic device, or memory-based device used as a control element.
• IP Code - The enclosure protection rating from IEC 60529 used to show protection against access and ingress.

Who uses EN IEC 60079-11:2024/prA1:2026?

EN IEC 60079-11:2024/prA1:2026 is used by manufacturers of intrinsically safe equipment, design engineers, test laboratories, certification bodies, and quality managers working with equipment for explosive atmospheres. It is especially relevant for designers of control circuits, sensors, gas detectors, handlights, caplights, PCB assemblies, current-limiting networks, and encapsulated components.

Buyers and technical reviewers use it when they need to compare a product’s protection concept, fault assumptions, and test evidence. Compliance teams use it to check that the circuit design, enclosure protection, and component selection match the required level of protection.

What changed in EN IEC 60079-11:2024/prA1:2026 from the previous edition?

Compared with IEC 60079-11:2023, Amendment 1 updates these areas:

• clarifies thermal ignition assessment for sealed components in 5.4.1
• adds and revises the wire-current method in 5.4.3
• aligns ingress-protection wording in 6.2.2 and 6.2.3 with IEC 60079-0
• reorganizes the separation rules in 6.5.1 and adds new detail for “ia”, “ib” and “ic”
• refines creepage and clearance illustration in 6.5.6.4
• updates encapsulation temperature and damage rules in 6.6.1
• clarifies resistor-based current limitation in 7.4.2
• revises inductor, semiconductor, shunt-limiting, programmable-component and PPTC device rules in Clause 7
• updates spark-test, PCB coating, and additional cell or supercapacitor tests in Clause 9
• revises Annex D transient-energy measurement and Annex G assessment procedure
• adds IEC 60287-1-1 and Dellinger data to the bibliography

Which standards are used with EN IEC 60079-11:2024/prA1:2026?

• IEC 60529 - provides the IP Code used for enclosure protection in Clauses 6.2.2 and 6.2.3.
• IEC 60079-0 - provides aligned explosive-atmospheres terminology and related safety requirements.
• IEC 60664-3 - provides the type-testing basis for PCB coatings in Clause 9.8.
• IEC 60079-25 - supports output-characteristic assessment and calculation of limiting power in Annex D and Annex G.
• IEC 60287-1-1 - is cited in the bibliography as a source related to current-rating equations for cables.

What does the EN IEC 60079-11:2024/prA1:2026 document contain?

The amendment contains updated requirements text, equations, examples, figures, and tables rather than only editorial changes. It revises Table 16 for semiconductor ratings and failure modes, Table 22 for PPTC devices, and the energy limits and measurement guidance in Annex D. It also updates Figure 4, Figure 20, Figure 21, Figure D.1, Figure D.2, Figure G.1, and the worked assessment examples in Annex G.

The document also includes practical test guidance for spark testing, PCB coating qualification, and additional thermal testing of cells or supercapacitors. Those parts are used by laboratories and certification engineers to set up tests, choose samples, and judge whether a design still meets intrinsic-safety limits under fault and transient conditions.

SLOVENSKI STANDARD
01-november-2026
Eksplozivne atmosfere - 11. del: Zaščita opreme z lastno varnostjo "i" - Dopolnilo 1
Amendment 1 - Explosive atmospheres - Part 11: Equipment protection by intrinsic
safety "i"
Explosionsgefährdete Bereiche - Teil 11: Geräteschutz durch Eigensicherheit "i"
Atmosphères explosives - Partie 11: Protection de l’appareil par sécurité intrinsèque "i"
Ta slovenski standard je istoveten z: EN IEC 60079-11:2024/prA1:2026
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.

31G/445/CDV
COMMITTEE DRAFT FOR VOTE (CDV)
PROJECT NUMBER:
IEC 60079-11/AMD1 ED7
DATE OF CIRCULATION: CLOSING DATE FOR VOTING:
2026-08-28 2026-11-20
SUPERSEDES DOCUMENTS:
31G/423/CD, 31G/428A/CC
IEC SC 31G : INTRINSICALLY-SAFE APPARATUS
SECRETARIAT: SECRETARY:
United Kingdom Mr Nicholas Ludlam
OF INTEREST TO THE FOLLOWING COMMITTEES: HORIZONTAL FUNCTION(S):
TC 18, SC 31J
ASPECTS CONCERNED:
Safety
SUBMITTED FOR CENELEC PARALLEL VOTING NOT SUBMITTED FOR CENELEC PARALLEL VOTING
Attention IEC-CENELEC parallel voting
The attention of IEC National Committees, members of CENELEC,
is drawn to the fact that this Committee Draft for Vote (CDV) is
submitted for parallel voting.
The CENELEC members are invited to vote through the CENELEC
online voting system.
This document is still under study and subject to change. It should not be used for reference purposes.
Recipients of this document are invited to submit, with their comments, notification of any relevant patent rights of which t hey are aware
and to provide supporting documentation.
Recipients of this document are invited to submit, with their comments, notification of any relevant “In Some Countries” clau ses to be
included should this proposal proceed. Recipients are reminded that the CDV stage is the final stage for submitting ISC c lauses. (SEE
AC/22/2007 OR NEW GUIDANCE DOC).

TITLE:
Amendment 1 – Explosive atmospheres – Part 11: Equipment protection by intrinsic safety "i"

PROPOSED STABILITY DATE: 2030
NOTE FROM TC/SC OFFICERS:
NCs are requested to submit any comments to the SC Secretary before 2026-11-06 to enable these to be discussed at
the next maintenance team meeting which is scheduled for Hamburg, DE on 2026-11-11.

electronic file, to make a copy and to print out the content for the sole purpose of preparing National Committee positions.
You may not copy or "mirror" the file or printed version of the document, o r any part of it, for any other purpose without
permission in writing from IEC.

IEC CDV 60079-11:2023/AMD1 © IEC 2026
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
EXPLOSIVE ATMOSPHERES –
Part 11: Equipment protection by intrinsic safety “i”

AMENDMENT 1
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-operation 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 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 agreement between the two
organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence between
any IEC Publication and the corresponding national or regional publication shall be clearly indicated in the latter.
5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
services carried out by independent certification bodies.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) IEC draw attention to the possibility that the implementation of this document may involve the use of (a) patent(s).
IEC takes no position concerning the evidence, validity or applicability of any claimed patent rights in respect
thereof. As of the date of publication of this document, IEC had not received notice of (a) patent(s), which may
be required to implement this document. However, implementers are cautioned that this may not represent the
latest information, which 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.
Amendment 1 to IEC 60079-11:2023 has been prepared by subcommittee 31G: Intrinsically
safe apparatus, of IEC technical committee 31: Equipment for explosive atmospheres.
The significance of changes between IEC 60079-11, Edition 7.1 (202X) and IEC 60079-11,
Edition 7 (2023) are as listed below:
IEC CDV 60079-11:2023/AMD1 © IEC 2026
Type
Minor and Major
editorial technical
Changes Clause Extension
changes changes
Clarification of application of the thermal ignition 5.4.1 X
concept for sealed components. Additon of examples.
Section modified for clarification. 5.4.3 X
Amendment for the term for ingress protection to align 6.2.2 X
with IEC 60079-0.
Amendment for the term for ingress protection to align 6.2.3 X
with IEC 60079-0.
Re-organisation of this into three sections covering 6.5.1 B3
General, “ia” and “ib”, and “ic”.
Modification to Figure 4 Example 11 to delete the ≥X 6.5.6.4 X
in two places.
Modification to list item a) to provide clarification for 6.6.1 X
the encapsulation of fuses.
Correction of typographical error of the referenced 7.4.2 X
clause number.
Rewording of the paragraph. 7.6.1 B4
Modification to the footnotes of Table 16. 7.7.2 X
Addition of paragraph to provide clarification for the 7.7.6 X
application of list items a), b) and c).
Modification to provide additional information on the 7.7.8 X
application of digital potentiometers and similar
device.
Modification of Table 22 to remove reference to I . 7.16.3 X
trip
Modification to paragraph one to remove the reference 9.8 X
to Annex A Table A.1. Addition, after paragraph one,
of two new paragraphs identifying the tests required
for type 1 protection and type 2 protection.
Clarification to the requirements. 9.14.1.4 X
Figure D.1 modified to separately identify the Annex D X
measurement points for voltage at the load and at the
shunt voltage limiting.
Figure modified. D.2  C32
Replacement of existing G.2 Non-linear sources with Annex G  C33
G.2 Assessment procedure.
NOTE The technical changes referred to include the significance of technical changes in the revised IEC Standard,
but they do not form an exhaustive list of all modifications from the previous version. More guidance may be found
by referring to the Redline Version of the standard.
Explanations:
A) Definitions
Minor and editorial changes clarification
decrease of technical requirements
minor technical 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.
Extension addition of technical options
IEC CDV 60079-11:2023/AMD1 © IEC 2026
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
conformity with the preceding edition.
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 always 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 clause B) below.
NOTE These changes represent current technological knowledge. However, these changes should not normally
have an influence on equipment already placed on the market.
B) Information about the background of Changes
B3 It is recognized that the clarified requirements in Ed. 7.0 were, in many cases, already
applied. The change in Edition. 7.0 was to ensure that the requirements were uniformly
and consistently applied. The extension in Amendment 1 provides further clarification
and additional options.
B4 The change in 7.6.1 is an extension compared to Edition 7.0, reverting back to the method
used in Edition. 6.0, because Ed. 7.0 was considered too strict (That is the matched
power in any inductor that was not compliant to 7.6.2).
C32 Figure D.1 modified to separately identify the measurement points for voltage at the load
and at the shunt voltage limiting.
C33 Process for linear sources is now the same as for non-linear sources to remove a
misunderstanding of the use of these curves. An additional enveloping stage has been
added where a safety factor of 1,5 is required as suggested by IEC 60079-25.

The text of this Amendment is based on the following documents:
Draft Report on voting
31G/XX/XXXX 31G/XX/XXX
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this Amendment is English.
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
described in greater detail at www.iec.ch/publications/.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under webstore.iec.ch in the data related to the
specific document. At this date, the document will be
• reconfirmed,
• withdrawn, or
• revised.
____________________
IEC CDV 60079-11:2023/AMD1 © IEC 2026
2 5.4 Thermal ignition compliance
3 5.4.1 General
4 Add, at the end of 5.4.1, the following new text.
5 For sealed components, except for fuses, the surface in contact with the explosive atmosphere
6 shall be considered to be the surface of the component package. For this purpose, surfaces
7 refer to the areas of the component that can be exposed to explosive atmosphere. This
8 assessment should take into account whether the explosive atmosphere can penetrate the
9 interior of components in sufficient quantities. A fault analysis in which the sealed component
10 is destroyed in order to evaluate heat sources inside does not usually need to be assumed for
11 thermal analysis.
12 EXAMPLES
13 Examples of sealed components are:
14 - a semiconductor which is fabricated into a package by the semiconductor manufacturer using moulding or
15 an equivalent process, such that the explosive atmosphere is excluded, such as Smart outline integrated
16 circuit (SOIC), Dual in-line package (DIP), Quad flat no-leads (QFN), Small outline transistor (SOT).
17 - resistors
18 Examples which are not normally considered as sealed components are:
19 - modules built from discrete components such as DC/DC converters
20 - relays
21 - transformers
23 5.4.3 Wiring within intrinsically safe apparatus for Group I and Group II
24 Replace the existing subclause 5.4.3 with the following new text and equations.
25 The maximum permissible current corresponding to the maximum wire temperature due to self-
26 heating shall either be taken from Table 3 for copper wires or can be calculated from the
27 following equation for metals in general.
tT− 1+α T −T
( )( ( ))
a a a
28 II=
f
(TT− ) 1+α (t−T )
( )
a a a
29 where
-1
30 α is the temperature coefficient of resistance per Kelvin (K ) of the wire material at T ;
a a
31 I is the maximum permissible current RMS, in amperes;
32 I is the current, in amperes at which the wire melts in an ambient temperature T ;
f a
33 T is the melting temperature of the wire material in degrees Celsius (°C) (for example,
34 1 083 °C for copper, 1 064 °C for gold);
35 T is the maximum local temperature in the vicinity of the wire in degrees Celsius (°C); and
a
36 t is the threshold temperature, in degrees Celsius (°C), for thermal ignition compliance. This
37 is also the resultant wire temperature due to self-heating and ambient temperature.
38 Where the temperature coefficient of resistance of the material is specified at an ambient
39 temperature other than T , α at T can be determined as follows:.
a a a
IEC CDV 60079-11:2023/AMD1 © IEC 2026
40 α =
a

+−TT
( )

ar1
α
r
41 Where:
42 T is the known reference ambient temperature in degrees Celsius (°C) at which α is
r1 r
43 applicable (for example, 0 °C);
-1 –1
44 α is the coefficient of resistance at T per Kelvin (K ) (for example, 0,004 27 K for copper
r r
–1
45 at 0 °C, 0,004 201 K for gold at 20 °C).
46 NOTE Various sources of data are available for the temperature coefficient of resistance, such as [1] Delliger,
47 IEC 60287-1-1, wire manufacturer’s data, or any other applicable data.
48 Where the melting current of the wire is available at a different ambient temperature to T (for
a
49 example, where the manufacturer of the wire specifies the melting current in the wire in an
50 ambient of 20 °C), then I may be determined as follows:
f
TT−
( )
a
51 II=
fr
(TT− )
r2
52 where:
53 I is the specified melting current, in amperes;
r
54 T is the reference temperature in degrees Celsius at which I is applicable
r2 r
55 EXAMPLE The maximum permissible current RMS for a fine copper wire with a surface area less than 20 mm
56 (Temperature class = T4)
–1
57 α = 0,004 64 K at T = 0 °C
r r
58 I = 1,6 A
f
59 T = 1 083 °C
60 T = 40 °C
a
61 t for T4 (Small component, t ≤ 275 °C)
62 Applying the equations for α and I:
a
63 I = 1,221 A (This is the maximum normal or fault current which may be allowed to flow to prevent the wire
64 temperature from exceeding 275 °C.)
65 6.2.2 Apparatus complying with Table 7
66 Replace the existing text of the first paragraph with the following new text .
67 Parts of apparatus relying on the separation requirements of Table 7 shall be provided with an
68 enclosure providing a degree of protection (IP Code) of at least IP2X in accordance with IEC
69 60529.
70 6.2.3 Apparatus complying with Table 8 or Table 9
71 Replace the existing text of list item a) with the following new text.
72 Parts of apparatus relying on the reduced separation requirements of Table 8 or Table 9 shall
73 be provided with protection for the separations on which intrinsic safety depends by one of the
74 following:
75 a) The enclosure shall provide a degree of protection (IP Code) of at least IP54 according to
76 IEC 60529 and meet the requirements of 6.2.5.1.
77 6.5 Separation of conductive parts
IEC CDV 60079-11:2023/AMD1 © IEC 2026
78 6.5.1 Separations on which intrinsic safety depends
79 Re-organisation of the section into three subclauses, General, requirements for “ia” and “ib”
80 and requirements for “ic”. Addition of new subclauses 6.5.1.2 and 6.5.1.3.
81 Addition of two new examples including Figures 20 and 21.
82 6.5.1.1 General
83 Where intrinsic safety depends on the separation between conductive parts of:
84 – intrinsically safe and non-intrinsically safe circuits,
85 – different intrinsically safe circuits,
86 – different parts of an intrinsically safe circuit, for example, across current limiting
87 components, or
88 – a circuit and earthed or isolated metal parts,
89 separation shall be maintained as necessary, in accordance with 6.5.2 and 6.5.3, following the
90 fault analysis of 6.5.4.
91 For Levels of Protection "ia" and "ib", this requirement applies to internal separations within
92 components unless stated otherwise in this document.
93 For Level of Protection "ic", this requirement does not apply to internal separations within
94 components unless stated otherwise in this document.
95 NOTE 1 Separations are additionally required by IEC 60079-0 to meet applicable safety requirements of relevant
96 industrial standards.
97 NOTE 2 Details about the different types of separation are given in 6.5.6.
98 Separation distances shall be measured or assessed taking into account any possible
99 movement of the conductors or conductive parts. Manufacturing tolerances shall not reduce
100 the distances below the minimum requirement by more than 10 % or 1 mm, whichever is the
101 smaller.
102 NOTE 3 Methods of assessment are given in Annex C.
104 6.5.1.2 Separations depending on insulating parts of prefabricated components for
105 Levels of Protection “ia” and “ib”
106 For Levels of Protection “ia” and “ib”, the insulating parts of prefabricated components shall
107 not be considered to provide separation between internal conductive parts of the component
108 and other conductive parts, except when one or more of the following is applied:
109 a) The thickness of the component insulation may be considered where it is specified by
110 the manufacturer of the component, or determined in accordance with 9.13, taking into
111 account the type of separation (for example, solid insulation).
112 b) Failure of the separation provided by the insulating parts of the component to a
113 conductive part directly connected, before the application of faults, to the component
114 is subject to a countable fault unless the separation is infallible.
EXAMPLE 1 A track under a resistor that is connected to the resistor, where the insulation thickness of
the resistor is unknown and the resistor is rated to 7.1. In this case, the failure of separation between the
internal conductive parts of the resistor and the track is a countable fault.
118 c) Failure of separation between any internal conductive parts of a component and its
119 solder pads do not need to be considered where the solder footprint is of similar design
120 to the recommendation of the manufacturer of the component.
121 d) Failure of separation between internal conductive parts of a component to tracks which
122 are connected to its solder pads do not need to be considered if the tracks do not
IEC CDV 60079-11:2023/AMD1 © IEC 2026
123 reduce the separation distance between the pads. However, once the track reaches
124 the separation distance required from the component by 6.5.4.2, the additional
125 separation distance to the pads no longer applies.
126 EXAMPLE 2 In Figure 20 the areas in yellow (key 3), purple (key 2) and orange (key 4) represent this concept.
127 The red arrow (key 7) in section Y indicates a failure of separation where section Z shows no failure of separation.
128 Dimensions in mm
130 Key
131 1 Tracks
132 2 Distance between pads, = 2,3 mm
133 3 Distance according to table 7 for 10 V = 1,5 mm
134 4 Overlap of 2 and 3
135 5 Pads
136 6 Indicator for separation failure
137 7 Component body
138 8 Dimension
139 Figure 20 – Spacing according to 6.5.1.2 d)
140 EXAMPLE 3 An SOT23 style component is shown in Figure 21. In this case the recommended solder footprint
141 design establishes a distance between the solder pads of 1,13 mm or 1,2 mm and the spacing requirement is 0,5
142 mm. The track under the component’s body is subjected to a countable fault according to b) as it maintains a
143 separation of 0,5 mm. It is not infallible according to d) as it violates the distance of 1,13 mm between the pads.
IEC CDV 60079-11:2023/AMD1 © IEC 2026
145 Dimensions in mm
148 Key
149 1 Tracks
150 2 Distance between pads, = 1,13 mm or 1,2 mm
151 3 Distance according to 6.5.1
152 4 Overlap of 2 and 3
153 5 Pads
154 6 Indicator for separation failure
155 7 Component body
156 8 Dimension
158 Figure 21 – Spacing according to 6.5.1.2 for a SOT23 style component
159 For thermal ignition assessment of a component, change of its impedance caused by failure of
160 separation between any internal conductive parts of that component and other conductive parts
161 need not be considered.
162 EXAMPLE 3 Other conductive parts could include pads, tracks, and adjacent components.
164 6.5.1.3 Separations depending on insulating parts of prefabricated components for Level
165 of Protection “ic”
166 For Level of Protection “ic”, the insulating parts of prefabricated components shall not be
167 considered to provide separation between internal conductive parts of the component and other
168 conductive parts, except when one or more of the following is applied:
169 a) The thickness of the component insulation may be considered where it is specified by the
170 manufacturer of the component, or determined in accordance with 9.13, taking into account
171 the type of separation (for example, solid insulation).
172 b) Where a component is rated according to 7.1 including for the voltage across the
173 separation, failure of the separation provided by the insulating parts of the component is
174 not subject to fault.
175 c) Failure of separation between any internal conductive parts of a component and its solder
176 pads do not need to be considered where the solder footprint is of similar design to the
177 recommendation of the manufacturer of the component.
IEC CDV 60079-11:2023/AMD1 © IEC 2026
178 d) Failure of separation between internal conductive parts of a component to tracks which are
179 connected to its solder pads do not need to be considered if they do not reduce the
180 separation between the pads. However, once the track reaches the separation distance
181 required from the component by 6.5.4.2, the additional separation distance to the pads no
182 longer applies.
184 6.5.6.4 Creepage distance
185 Replacement of Figure 4 Example 11 with the following new Example 11.
186 Example 11
Clearance is the distance d + D
Creepage distance is also d + D
C' conductive part interposed in the insulating path
between the conductors
191 clearance creepage distance
192 Figure 4 (5 of 5)
193 Figure 4 – Determination of creepage distances and clearance
195 6.6 Encapsulation
196 6.6.1 General
197 Replacement of item a) with the following new text.
198 a) For fuses, the COT of the compound shall be suitable for the ambient temperature range.
199 For all other components (if applicable):
200 1) Under normal operating conditions, the maximum and minimum temperature at the
201 interface between the compound and any encapsulated component or part shall not
202 exceed the COT of the compound as specified by the manufacturer of the compound.
203 2) Under the conditions specified in 5.2 other than normal operating conditions,
204 temperatures higher than the compound's COT rating are permitted if there is no
205 damage to the compound both internally and externally that could invalidate intrinsic
206 safety.
207 EXAMPLE Damage that can invalidate intrinsic safety includes cracks in the co
...