SIST EN 60079-26:2007

SLOVENSKI STANDARD
SIST EN 60079-26:2007
01-november-2007
1DGRPHãþD
SIST EN 60079-26:2005
(NVSOR]LYQHDWPRVIHUHGHO2SUHPDVVWRSQMR]DãþLWH(3/*D,(&

Explosive atmospheres - Part 26: Equipment with equipment protection level (EPL) Ga
Explosionsfhige Atmosphre - Teil 26: Betriebsmittel mit Gerteschutzniveau (EPL) Ga
Atmosphres explosives - Partie 26: Matriel d'un niveau de protection du matriel (EPL) Ga
Ta slovenski standard je istoveten z: EN 60079-26:2007
ICS:
29.260.20 (OHNWULþQLDSDUDWL]D Electrical apparatus for
HNVSOR]LYQDR]UDþMD explosive atmospheres
SIST EN 60079-26:2007 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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EUROPEAN STANDARD
EN 60079-26

NORME EUROPÉENNE
March 2007
EUROPÄISCHE NORM

ICS 29.260.20 Supersedes EN 60079-26:2004


English version


Explosive atmospheres -
Part 26: Equipment with equipment protection level (EPL) Ga
(IEC 60079-26:2006)


Atmosphères explosives -  Explosionsfähige Atmosphäre -
Partie 26: Matériel d'un niveau Teil 26: Betriebsmittel
de protection du matériel (EPL) Ga mit Geräteschutzniveau (EPL) Ga
(CEI 60079-26:2006) (IEC 60079-26:2006)




This European Standard was approved by CENELEC on 2006-10-01. CENELEC members are bound to comply
with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard
the status of a national standard without any alteration.

Up-to-date lists and bibliographical references concerning such national standards may be obtained on
application to the Central Secretariat or to any CENELEC member.

This European Standard exists in three official versions (English, French, German). A version in any other
language made by translation under the responsibility of a CENELEC member into its own language and notified
to the Central Secretariat has the same status as the official versions.

CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Cyprus, the
Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain,
Sweden, Switzerland and the United Kingdom.

CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung

Central Secretariat: rue de Stassart 35, B - 1050 Brussels


© 2007 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. EN 60079-26:2007 E

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EN 60079-26:2007 - 2 -
Foreword
The text of document 31/630/FDIS, future edition 2 of IEC 60079-26, prepared by IEC TC 31, Equipment
for explosive atmospheres, was submitted to the IEC-CENELEC parallel vote and was approved by
CENELEC as EN 60079-26 on 2006-10-01.
This European Standard supersedes EN 60079-26:2004.
The significant changes with respect to EN 60079-26:2004 are:
– changes concerning the accessible chargeable surfaces of the equipment;
– requirements of a partition wall combined with an air-gap with natural ventilation;
– introduction of equipment protection levels (EPL) and substitution of the references to zones (see
explanation in Annex A);
– change of heading from “Mechanical connection” to “Process connection” together with a clarification
of requirement for any release from Zone 0 of explosive gas atmospheres.
The following dates were fixed:
– latest date by which the EN has to be implemented
at national level by publication of an identical
national standard or by endorsement (dop) 2007-10-01
– latest date by which the national standards conflicting
with the EN have to be withdrawn (dow) 2009-10-01
This European Standard has been prepared under a mandate given to CENELEC by the European
Commission and the European Free Trade Association and covers essential requirements of
EC Directive 94/9/EC. See Annex ZZ.
This European Standard covers Category 1G and combined Category 1/2G electrical equipment.
NOTE Other EC Directives may be applicable
To be in line with the requirements given in Directive 94/9/EC the text given in the body of the standard
should be interpreted as given in the following table.
Text given in EN 60079-26 Adaptation to Directive 94/9/EC
Part 26: Equipment with equipment protection Part 26: Construction, test and marking of
level (EPL) Ga Group II Category 1G electrical equipment
EPL Ga equipment Category 1G equipment
EPL Gb type of protection Category 2G type of protection
Instead of the marking requirements given in Clause 6 of this standard, the apparatus shall be marked
according to the requirements of the Directive 94/9/EC for equipment Group II, Category 1G.
Apparatus intended for installation in the boundary wall between areas requiring different categories shall
have both categories marked on the label separated by a “/” (see examples below). Additionally, the
apparatus shall be marked according to the type of protection as defined in Clause 6.

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- 3 - EN 60079-26:2007
Examples of marking in compliance with Directive 94/9/EC
a) Apparatus which is intended to be completely installed inside the Zone 0 area for example:
II 1G
b) Associated apparatus, which is installed outside the hazardous area and providing external electrical
circuits protected by intrinsic safety “ia” according to EN 60079-11, which can be connected to
Category 1 apparatus , for example:
II (1)G
NOTE  No designation of the temperature class is required, as this apparatus is located outside the hazardous area.
c) Equipment which is installed in the boundary wall between areas requiring different categories, both
categories are marked on the label separated by a slash for example:
II 1/2G

Annexes ZA and ZZ have been added by CENELEC.
__________
Endorsement notice
The text of the International Standard IEC 60079-26:2006 was approved by CENELEC as a European
Standard without any modification.
In the official version, for Bibliography, the following notes have to be added for the standards indicated:
IEC 60079-2 NOTE  Harmonized as EN 60079-2:2004 (not modified).
IEC 60079-7 NOTE  Harmonized as EN 60079-7:2007 (not modified).
IEC 60079-14 NOTE  Harmonized as EN 60079-14:2003 (not modified).
IEC 60079-15 NOTE  Harmonized as EN 60079-15:2005 (not modified).
IEC 60079-26 NOTE  Harmonized as EN 60079-26:2004 (not modified).
IEC 60079-28 NOTE  Harmonized as EN 60079-28:2007 (not modified).
IEC 60529 NOTE  Harmonized as EN 60529:1991 (not modified).
IEC 61241-0 NOTE  Harmonized as EN 61241-0:2006 (modified).
IEC 61241-4 NOTE  Harmonized as EN 61241-4:2006 (not modified).
IEC 61241-10 NOTE  Harmonized as EN 61241-10:2004 (not modified).
IEC 61241-11 NOTE  Harmonized as EN 61241-11:2006 (not modified).
IEC 61241-18 NOTE  Harmonized as EN 61241-18:2004 (not modified).
__________

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EN 60079-26:2007 - 4 -
Annex ZA
(normative)

Normative references to international publications
with their corresponding European publications

The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.

NOTE  When an international publication has been modified by common modifications, indicated by (mod), the relevant EN/HD
applies.

Publication Year Title EN/HD Year
IEC 60079-0 (mod) 2004 Electrical apparatus for explosive gas EN 60079-0 2006
atmospheres -
Part 0: General requirements


1) 2)
IEC 60079-1 - Electrical apparatus for explosive gas EN 60079-1 2004
atmospheres - + corr. April 2006
Part 1: Flameproof enclosures 'd'


1) 2)
IEC 60079-10 - Electrical apparatus for explosive gas EN 60079-10 2003
atmospheres -
Part 10: Classification of hazardous areas


1) 2)
IEC 60079-11 - Explosive atmospheres - EN 60079-11 2006
Part 11: Equipment protection by intrinsic
safety "i"


1) 2)
IEC 60079-18 - Electrical apparatus for explosive gas EN 60079-18 2004
atmospheres - + corr. April 2006
Part 18: Construction, test and marking of
type of protection encapsulation "m"
electrical apparatus


1) 2)
IEC 60695-11-10 - Fire hazard testing - EN 60695-11-10 1999
Part 11-10: Test flames - 50 W horizontal
and vertical flame test methods




1)
Undated reference.
2)
Valid edition at date of issue.

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- 5 - EN 60079-26:2007
Annex ZZ
(informative)

Coverage of Essential Requirements of EC Directives
This European Standard has been prepared under a mandate given to CENELEC by the European
Commission and the European Free Trade Association and within its scope the standard covers only the
following essential requirements out of those given in Annex II of the EC Directive 94/9/EC:
– ER 1.0.1 to ER 1.0.4, ER 1.0.5 (partly), ER 1.0.6 (partly)
– ER 1.1
– ER 1.2.1 (partly), ER 1.2.3, ER 1.2.5 (partly), ER 1.2.8, ER 1.2.9
– ER 1.3.1 (partly), ER 1.3.2 (partly), ER 1.3.3 (partly), ER 1.3.14 (partly)
– ER 1.4.2 (partly)
– ER 2.1.1.1, ER 2.1.1.2
Compliance with this standard provides one means of conformity with the specified essential
requirements of the Directive concerned.
WARNING: Other requirements and other EC Directives may be applicable to the products falling within
the scope of this standard.
__________

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NORME CEI
INTERNATIONALE
IEC



60079-26
INTERNATIONAL


Deuxième édition
STANDARD

Second edition

2006-08


Atmosphères explosives –
Partie 26:
Matériel d'un niveau de protection
du matériel (EPL) Ga

Explosive atmospheres –
Part 26:
Equipment with equipment protection
level (EPL) Ga

 IEC 2006 Droits de reproduction réservés  Copyright - all rights reserved
Aucune partie de cette publication ne peut être reproduite ni No part of this publication may be reproduced or utilized in any
utilisée sous quelque forme que ce soit et par aucun procédé, form or by any means, electronic or mechanical, including
électronique ou mécanique, y compris la photocopie et les photocopying and microfilm, without permission in writing from
microfilms, sans l'accord écrit de l'éditeur. the publisher.
International Electrotechnical Commission, 3, rue de Varembé, PO Box 131, CH-1211 Geneva 20, Switzerland
Telephone: +41 22 919 02 11 Telefax: +41 22 919 03 00 E-mail: inmail@iec.ch Web: www.iec.ch
CODE PRIX
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PRICE CODE
Commission Electrotechnique Internationale
International Electrotechnical Commission
МеждународнаяЭлектротехническаяКомиссия
Pour prix, voir catalogue en vigueur
For price, see current catalogue

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60079-26  IEC:2006 – 3 –
CONTENTS
FOREWORD.5

1 Scope.9
2 Normative references.11
3 Terms and definitions .11
4 Requirements for design and construction.11
4.1 General .11
4.2 Protection measures against ignition hazards of the electrical circuits .11
4.3 Equipment with moving parts .23
4.4 Isolated conductive components .23
4.5 Non-conductive enclosures and accessible non-conductive components .25
4.6 Process connection .27
5 Type tests.27
5.1 Standardized types of protection .27
5.2 Separation elements.27
5.3 Temperature evaluation .27
6 Marking .29
6.1 General .29
6.2 Examples of marking .29
7 Information for use.29

Annex A (informative) Introduction of an alternative risk assessment method
encompassing “equipment protection levels” for Ex equipment .31

Bibliography .41

Figure 1 – Example of a partition wall with a conductor bushing being considered gas
diffusion tight .17
Figure 2 – Example of a separation element with a cylindrical shaft joint and natural
ventilation .23

Table 1 – Separation elements .19
Table A.1 – Traditional relationship of EPLs to zones (no additional risk assessment).35
Table A.2 – Description of risk of ignition protection provided .37

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60079-26  IEC:2006 – 5 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________

EXPLOSIVE ATMOSPHERES –

Part 26: Equipment with equipment protection level
(EPL) Ga


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 provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with an IEC Publication.
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) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 60079-26 has been prepared by IEC technical committee 31:
Equipment for explosive atmospheres.
This second edition cancels and replaces the first edition published in 2004 and constitutes a
technical revision.
The significant changes with respect to the previous edition are listed below:
– changes concerning the accessible chargeable surfaces of the equipment;
– requirements of a partition wall combined with an air-gap with natural ventilation;

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60079-26  IEC:2006 – 7 –
– introduction of equipment protection levels (EPL) and substitution of the references to
zones (see explanation in Annex A);
– change of heading from “Mechanical connection” to “Process connection” together with a
clarification of requirement for any release from zone 0 of explosive gas atmospheres.
The text of this standard is based on the following documents:
FDIS Report on voting
31/630/FDIS 31/649/RVD

Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all parts of the IEC 60079 series, under the general title: Explosives atmospheres, can
be found on the IEC website.
The committee has decided that the contents of this publication will remain unchanged until the
maintenance result date indicated on the IEC web site under "http://webstore.iec.ch" in the data
related to the specific publication. At this date, the publication will be
• reconfirmed;
• withdrawn;
• replaced by a revised edition, or
• amended.

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60079-26  IEC:2006 – 9 –
EXPLOSIVE ATMOSPHERES –

Part 26: Equipment with equipment protection level
(EPL) Ga



1 Scope
This part of IEC 60079 specifies the particular requirements for construction, test and marking
for electrical equipment that provides equipment protection level (EPL) Ga. This electrical
equipment, within the operational parameters specified by the manufacturer, ensures a very
high level of protection that includes rare faults related to the equipment or two faults occurring
independently of each other.
NOTE 1 A malfunction may result from a failure of the component parts of the electrical equipment or from
anticipated externally applied influences. Two independent malfunctions which may occur more frequently and
which, separately, would not create an ignition hazard but which, in combination, could create a potential ignition
hazard, should be regarded as occurring together to form a rare fault.
NOTE 2 This electrical equipment is intended for use in zone 0 hazardous areas, in which explosive gas
atmospheres caused by mixtures of air and gases, vapours or mists under normal atmospheric conditions are
present continuously, for long periods or frequently.
This standard also applies to equipment mounted across a boundary where different protection
levels may be required.
EXAMPLE: In the wall of a storage vessel containing zone 0 with an ambient defined as zone 1.
This standard also applies to equipment installed in an area requiring a lower protection level,
but electrically connected to equipment with equipment protection level (EPL) Ga (associated
apparatus).
This standard supplements the general requirements in IEC 60079-0 and the requirements of
the standardized types of protection, in accordance with the IEC 60079 series, to adapt the
level of safety provided by those standards in order to provide EPL Ga.
NOTE 3 In designing equipment for operation in explosive gas atmospheres under conditions other than the
atmospheric conditions given in IEC 60079-0, this standard may be used as a guide. However, additional testing is
recommended related specifically to the intended conditions of use. This is particularly important when the types of
protection ‘Flameproof enclosures’ (IEC 60079-1) and ‘Intrinsic safety’ (IEC 60079-11) are applied.
NOTE 4 The classification of hazardous areas in zones is defined in IEC 60079-10.
NOTE 5 There may be other non-electrical sources of ignition (for example ultrasonic, optical or ionizing radiation)
that are not addressed by this standard; these should also be taken into consideration (see, for example, EN 1127-1).
NOTE 6 This concept provides equipment protection level (EPL) Ga. For further information, see Annex A.

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60079-26  IEC:2006 – 11 –
2 Normative references
The following referenced documents are indispensable for the application of this document. For
dated references, only the edition cited applies. For undated references, the latest edition of
the referenced document (including any amendments) applies.
IEC 60079-0:2004, Electrical apparatus for explosive gas atmospheres – Part 0: General
requirements
IEC 60079-1, Electrical apparatus for explosive gas atmospheres – Part 1: Flameproof
enclosures "d"
IEC 60079-10, Electrical apparatus for explosive gas atmospheres – Part 10: Classification of
hazardous areas
IEC 60079-11, Explosive atmospheres – Part 11: Equipment protection by intrinsic safety "i"
IEC 60079-18, Electrical apparatus for explosive gas atmospheres – Part 18: Construction, test
and marking of type of protection encapsulation "m" electrical apparatus
IEC 60695-11-10, Fire hazard testing – Part 11-10: Test flames – 50 W horizontal and vertical
flame test methods
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 60079-0 apply,
together with the following abbreviation.
NOTE Additional definitions applicable to explosive atmospheres can be found in IEC 60050-426.
3.1
EPL
abbreviation of equipment protection level as defined in Annex A
4 Requirements for design and construction
4.1 General
The equipment shall comply with the requirements of 4.2 for the electrical circuits and with the
requirements of 4.3 to 4.6 for mechanical and electrostatic ignition hazards.
4.2 Protection measures against ignition hazards of the electrical circuits
4.2.1 General
The equipment shall comply with the requirements of either
a) 4.2.2 or 4.2.3 in the event of two faults occurring independently of each other in a single
equipment means of protection; or
b) 4.2.4 or 4.2.5 in the event of a failure of one equipment means of protection, by the
provision of a second independent means of protection.

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60079-26  IEC:2006 – 13 –
Electrical connections and permanently connected cables of the equipment sited within an area
requiring EPL Ga equipment shall comply with the same level of protection required by this
standard, for example an Ex “e” cable containing non-Ex ia circuits additionally protected by a
flameproof conduit or an Ex “e” cable provided with an earth leakage protection.
NOTE 1 Detailed cable and installation requirements for non-intrinsically safe circuits providing EPL Ga are in
consideration in IEC 60079-14.
NOTE 2 Because of ignition hazards which can arise from faults and/or transient circulating currents in the
potential equalization system, galvanic isolation in the power and signal connections to the equipment according to
4.2.2, 4.2.3 and 4.2.4 is preferred. Consideration should also be given to minimize the effect of transient fault
currents in the potential equalization network by the use of electrical protection equipment such as sensitive earth
leakage monitors.
4.2.2 Intrinsic safety as a sole means of protection
Intrinsically safe electrical equipment providing EPL Ga and intrinsically safe electrical circuits
of associated apparatus entering an area requiring EPL Ga shall comply with the requirements
of IEC 60079-11, intrinsic safety “ia”.
NOTE Intrinsic safety “ib” in accordance with IEC 60079-11 may be considered as one of two independent means
of protection according to 4.2.4.
4.2.3 Encapsulation as a sole means of protection
Electrical equipment which is protected by encapsulation providing EPL Ga shall comply with
the requirements of IEC 60079-18, encapsulation “ma”.
NOTE Encapsulation “mb” in accordance with IEC 60079-18 may be considered as one of two independent means
of protection according to 4.2.4.
4.2.4 Application of two independent types of protection providing EPL Gb
Electrical equipment shall comply with the requirements of two independent types of protection
that provide EPL Gb. If one type of protection fails, the other type of protection shall continue to
function. The independent types of protection shall not have a common mode of failure, except
as specified in this clause.
An example of a common mode failure is if an Ex “d” enclosure with arcing contacts inside it is
used inside an Ex “e” enclosure. If the Ex “d” enclosure is compromised, then arcing inside the
enclosure will also compromise the Ex “e” enclosure.
NOTE Combined types of protection providing EPL Gb should depend on different physical protection principles.
For example the combination of Ex “d” and Ex “q” both depend on the avoidance of flame propagation and may not
be useful in combination. In practice, some combinations may not be useful, for example the combination of oil and
powder filling.
Where combined types of protection are used, it shall be possible for each type of protection to
be tested individually (see 5.1).
Both types of protection shall be assessed using the most arduous fault condition of the other
type of protection. When combining intrinsic safety, type of protection “ib”, with other types of
protection, the second type of protection shall be assessed, with the most arduous fault
condition applied to the intrinsically safe circuit.
When using two types of protection, which rely both on the same parameter (for example, the
creepage distance combining Ex “ib” with Ex “e”), the most stringent requirement of both types
of protection shall be applied.

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60079-26  IEC:2006 – 15 –
If two types of protection are combined which both rely on the enclosure, one of the following
shall be met:
a) if two enclosures are used (one totally enclosed within the other), each enclosure shall
comply with the requirements of the respective type of protection; or
b) if only one enclosure is used, the enclosure and the cable glands shall meet the impact test
requirements of 26.4.2 of IEC 60079-0, using the group I values.
Examples of combinations of two independent types of protection are as follows:
– inductive transmitters (for example proximity switches, electrical position sensors) with
intrinsic safety “ib” enclosed by encapsulation “mb”. The connections to intrinsically safe
“ib” circuits can be protected by the increased safety “e”;
– a lamp with the bulb designed as increased safety “e”, the lamp circuit with the switch as
intrinsic safety “ib”. These components may be incorporated in a flameproof enclosure “d”;
– measuring transducers with intrinsic safety “ib” and a flameproof enclosure “d”;
– equipment with electrical circuits of intrinsic safety “ib”, additionally protected by a powder
filling “q”;
– electromagnetic valves with encapsulation “mb”, enclosed by a flameproof enclosure “d”;
– increased safety “e”, with pressurized equipment “px”.
4.2.5 Application of a type of protection providing EPL Gb and a separation element
4.2.5.1 General
Equipment which is mounted through or forming part of the boundary wall to an area requiring
EPL Ga and containing electrical circuits which do not comply with protection level Ga shall
comply at least with one of the types of protection providing
...