EN 60079-26:2004

SLOVENSKI SIST EN 60079-26:2005

STANDARD
april 2005
Električne naprave za eksplozivne plinske atmosfere - 26. del: Konstrukcija,
preskušanje in označevanje električnih naprav skupine II kategorije 1G (IEC
60079-26:2004, spremenjen)
Electrical apparatus for explosive gas atmospheres – Part 26: Construction, test
and marking of Group II Category 1 G electrical apparatus
ICS 29.260.20 Referenčna številka
©  Standard je založil in izdal Slovenski inštitut za standardizacijo. Razmnoževanje ali kopiranje celote ali delov tega dokumenta ni dovoljeno

EUROPEAN STANDARD EN 60079-26
NORME EUROPÉENNE
EUROPÄISCHE NORM December 2004

ICS 29.260.20 Supersedes EN 50284:1999

English version
Electrical apparatus for explosive gas atmospheres
Part 26: Construction, test and marking
of Group II Category 1 G electrical apparatus
(IEC 60079-26:2004, modified)
Matériel électrique pour atmosphères Elektrische Betriebsmittel für
explosives gazeuses gasexplosionsgefährdete Bereiche
Partie 26: Construction, essais et Teil 26: Konstruktion, Prüfung und
marquage des matériels électriques Kennzeichnung elektrischer Betriebsmittel
de Groupe II Catégorie 1 G für Gruppe II Kategorie 1 G
(CEI 60079-26:2004, modifiée) (IEC 60079-26:2004, modifiziert)

This European Standard was approved by CENELEC on 2004-04-01. 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, Cyprus, Czech
Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden,
Switzerland and 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

© 2004 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.

Ref. No. EN 60079-26:2004 E
Foreword
The text of document 31/483/FDIS, future edition 1 of IEC 60079-26, prepared by IEC TC 31,
Electrical apparatus for explosive atmospheres, was submitted to the IEC-CENELEC parallel vote and
was approved by CENELEC as EN 60079-26 on 2004-04-01.
Directive 94/9/EC requires equipment classification according to categories. Therefore, in all clauses
where the text of IEC 60079-26 uses the term "Zone 0 Equipment", or equivalent, this shall be
interpreted as referring to equipment of Category 1 G.
To this end, a draft amendment, prepared by the Technical Committee CENELEC TC 31, Electrical
apparatus for explosive atmospheres - General requirements, was submitted to the formal vote and was
approved by CENELEC for inclusion into EN 60079-26 on 2004-09-22.
This European Standard supersedes EN 50284:1999.
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) 2005-06-01
– latest date by which the national standards conflicting
with the EN have to be withdrawn (dow) 2007-04-01
__________
Endorsement notice
The text of the International Standard IEC 60079-26:2004 was approved by CENELEC as a European
Standard with agreed common modifications as given below.
COMMON MODIFICATIONS
Replace the title by:
Electrical apparatus for explosive gas atmospheres – Part 26: Construction, test and marking of Group II
Category 1 G electrical apparatus.
Replace Clause 6 by:
6  Marking
6.1  General
The apparatus shall be marked according to the requirements of the Directive 94/9/EC for equipment
Group II, Category 1 G and according to the type of protection as defined in the applicable standard.
Apparatus intended for installation in the boundary wall between areas requiring different categories
shall have both categories marked on the label separated by a “/” and the corresponding symbols for
each type of protection separated by a “/”. In the case where the apparatus group or temperature class
differ for the two types of protection, the complete designation of each rating shall be used and
separated by a “/”.
- 3 - EN 60079-26:2004
Where more than one type of protection is used in accordance with 4.2.4, the symbols for the types of
protection shall be joined with a “+”.
6.2  Examples of marking
a) Apparatus which is intended to be completely installed inside the Zone 0 area for example:
II 1 G Ex ia IIC T6
or
II 1 G Ex d+e IIB T4
b) Associated apparatus, which is installed outside the hazardous area and providing external
electrical circuits protected by intrinsic safety “ia” according to EN 50020, which can be connected
to Category 1 apparatus , for example:
II (1) G [Ex ia] IIC
NOTE 1  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:
II1/2 G Ex d IIC T6
or
II 1/2 G Ex ia/d IIC T6
NOTE 2  Intrinsic safety “ia” apparatus in Zone 0 with a flameproof “d” compartment in Zone 1.
or
II 1/2 G Ex d+e/d IIB T4
NOTE 3  Two independent types of protection flameproof “d” and increased safety “e” in Zone 0 with a flameproof “d”
compartment in Zone 1.
The documentation shall state which parts of the apparatus are suitable for installation in each zone.
__________
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 Where an international publication has been modified by common modifications, indicated by (mod), the relevant
EN/HD applies.
Publication Year Title EN/HD Year
1) 2)
IEC 60079-0 – Electrical apparatus for explosive gas EN 60079-0 2004
atmospheres
Part 0: General requirements
1) 2)
IEC 60079-1 – Electrical apparatus for explosive gas EN 60079-1 2004
atmospheres
Part 1: Flameproof enclosures 'd'

1) 2)
IEC 60079-10 – Part 10: Classification of hazardous areas EN 60079-10 2003

1)
IEC 60079-11 – Part 11: Intrinsic safety "i" - -

1) 2)
IEC 60079-14 – Part 14: Electrical installations in EN 60079-14 2003
hazardous areas (other than mines)

1) 2)
IEC 60079-18 – Part 18: Construction, test and marking of EN 60079-18 2004
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.

NORME CEI
INTERNATIONALE
IEC
60079-26
INTERNATIONAL
Première édition
STANDARD
First edition
2004-03
Matériel électrique pour atmosphères
explosives gazeuses –
Partie 26:
Construction, essais et marquage
des matériels électriques de Groupe II
utilisables en Zone 0
Electrical apparatus for explosive
gas atmospheres –
Part 26:
Construction, test and marking
of Group II Zone 0 electrical apparatus
 IEC 2004 Droits de reproduction réservés  Copyright - all rights reserved
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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.
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For price, see current catalogue

60079-26  IEC:2004 – 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 .13
4.3 Apparatus with moving parts .23
4.4 Isolated conductive components .25
4.5 Non-conductive enclosures and accessible non-conductive components .25
4.6 Mechanical connection.27
5 Type tests.29
5.1 Standardized types of protection .29
5.2 Separation elements.29
5.3 Temperature evaluation.29
6 Marking.29
6.1 General.29
6.2 Examples of marking .29
7 Information for use.31

Bibliography .33

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 .21

60079-26  IEC:2004 – 5 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
ELECTRICAL APPARATUS FOR EXPLOSIVE GAS ATMOSPHERES –

Part 26: Construction, test and marking
of Group II Zone 0 electrical apparatus

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
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