Explosive atmospheres - Part 6: Equipment protection by liquid immersion "o" (IEC 60079-6:2015)

This part of IEC 60079 specifies the requirements for the design, construction, testing and
marking of Ex Equipment and Ex Components with type of protection liquid immersion “o”
intended for use in explosive gas atmospheres.
Ex Equipment and Ex Components of type of protection liquid immersion “o” are either:
• Level of Protection “ob” (EPL “Mb” or “Gb”)
• Level of Protection “oc” (EPL “Gc”)
For Level of Protection “ob”, this standard applies where the rated voltage does not exceed
11 kV r.m.s. a.c. or d.c.
For Level of Protection “oc”, this standard applies where the rated voltage does not exceed
15 kV r.m.s. a.c. or d.c.
NOTE Requirements for higher voltages are under consideration.
This standard supplements and modifies the general requirements of IEC 60079-0. Where a
requirement of this standard conflicts with a requirement of IEC 60079-0, the requirement of
this standard takes precedence.

Explosionsgefährdete Bereiche - Teil 6: Geräteschutz durch Flüssigkeitskapselung "o" (IEC 60079-6:2015)

Atmosphères explosives - Partie 6: Protection du matériel par immersion dans le liquide "o" (IEC 60079-6:2015)

L'IEC 60079-6:2015 spécifie les exigences de conception, de construction, d'essais et de marquage d'un matériel Ex et de composants Ex, de mode de protection immersion dans le liquide "o", destinés à être utilisés dans des atmosphères explosives gazeuses. Un matériel Ex et des composants Ex de mode de protection immersion dans le liquide "o" peuvent être du: Niveau de Protection "ob" (EPL "Mb" ou "Gb"), ou Niveau de Protection "oc" (EPL "Gc"). Pour le Niveau de Protection "ob", la présente norme s'applique si la tension assignée est inférieure à 11 kV eff. c.a. ou c.c. Pour le Niveau de Protection "oc", la présente norme s'applique si la tension assignée est inférieure à 15 kV eff. c.a. ou c.c. La présente norme complète et modifie les exigences générales de l'IEC 60079-0. Lorsqu'une exigence de la présente norme entre en contradiction avec une exigence de l'IEC 60079-0, l'exigence de la présente norme prévaut. Cette quatrième édition annule et remplace la troisième édition parue en 2007. Cette édition constitue une révision technique. Les modifications majeures par rapport à l'édition précédente sont énumérées ci-dessous: - Cette quatrième édition introduit une révision technique majeure des exigences relatives à l'immersion dans l'huile "o", et il convient qu'elle soit considérée comme spécifiant de nouvelles exigences. Le "Tableau des modifications majeures" habituel n'a pas été inclus pour cette raison. En particulier: - Les exigences relatives à l'immersion dans l'huile "o" traitent désormais de l'immersion dans un liquide, de niveaux de protection "ob" et "oc", selon les recommandations des réponses au document 31/715/DC; - La capacité à protéger les contacts à décharge disruptive a été ajoutée aux niveaux de protection "ob" et "oc". Des exigences supplémentaires relatives au liquide de protection ont été introduites. Mots clés: matériel Ex et de composants Ex, de mode de protection immersion dans le liquide "o"

Eksplozivne atmosfere - 6. del: Zaščita opreme s potopitvijo v olje "o" (IEC 60079-6:2015)

Ta del standarda IEC 60079 določa zahteve za načrtovanje, konstrukcijo, preskušanje in označevanje opreme in komponent EX z zaščito s potopitvijo v olje »o«, ki je namenjena uporabi v eksplozivnih plinskih atmosferah.
Oprema in komponente Ex z zaščito s potopitvijo v olje »o« imajo:
• nivo zaščite »ob« (EPL »Mb« ali »Gb«)
• nivo zaščite »oc« (EPL »Gc«)
V okviru nivoja zaščite »ob« se ta standard uporablja, če efektivna izmenična ali enosmerna napetost ne presega 11 kV.
V okviru nivoja zaščite »oc« se ta standard uporablja, če efektivna izmenična ali enosmerna napetost ne presega 15 kV.
OPOMBA: Zahteve za višje napetosti so v obravnavi.
Ta standard dopolnjuje in spreminja splošne zahteve standarda IEC 60079-0. Kadar je zahteva iz tega standarda v nasprotju z zahtevo iz standarda IEC 60079-0, ima prednost zahteva iz tega standarda.

General Information

Status
Published
Publication Date
25-Feb-2016
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
28-Dec-2015
Due Date
03-Mar-2016
Completion Date
26-Feb-2016

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SLOVENSKI STANDARD
SIST EN 60079-6:2016
01-april-2016
1DGRPHãþD
SIST EN 60079-6:2007

(NVSOR]LYQHDWPRVIHUHGHO=DãþLWDRSUHPHVSRWRSLWYLMRYROMHR ,(&



Explosive atmospheres - Part 6: Equipment protection by liquid immersion "o" (IEC

60079-6:2015)
Explosionsgefährdete Bereiche - Teil 6: Geräteschutz durch Flüssigkeitskapselung
"o" (IEC 60079-6:2015)

Atmosphères explosives - Partie 6: Protection du matériel par immersion dans le liquide

"o" (IEC 60079-6:2015)
Ta slovenski standard je istoveten z: EN 60079-6:2015
ICS:
29.260.20 (OHNWULþQLDSDUDWL]D Electrical apparatus for
HNVSOR]LYQDR]UDþMD explosive atmospheres
SIST EN 60079-6:2016 en

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
SIST EN 60079-6:2016
---------------------- Page: 2 ----------------------
SIST EN 60079-6:2016
EUROPEAN STANDARD EN 60079-6
NORME EUROPÉENNE
EUROPÄISCHE NORM
December 2015
ICS 29.260.20 Supersedes EN 60079-6:2007
English Version
Explosive atmospheres - Part 6: Equipment protection by liquid
immersion "o"
(IEC 60079-6:2015)

Atmosphères explosives - Partie 6: Protection du matériel Explosionsgefährdete Bereiche - Teil 6: Geräteschutz durch

par immersion dans le liquide "o" Flüssigkeitskapselung "o"
(IEC 60079-6:2015) (IEC 60079-6:2015)

This European Standard was approved by CENELEC on 2015-03-27. 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 CEN-CENELEC

Management Centre 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 CEN-CENELEC Management Centre has the

same status as the official versions.

CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic,

Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,

Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland,

Turkey and the United Kingdom.
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels

© 2015 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.

Ref. No. EN 60079-6:2015 E
---------------------- Page: 3 ----------------------
SIST EN 60079-6:2016
EN 60079-6:2015 (E)
European foreword

The text of document 31/1157/FDIS, future edition 4 of IEC 60079-6, prepared by IEC/TC 31

"Equipment for explosive atmospheres" was submitted to the IEC-CENELEC parallel vote and

approved by CENELEC as EN 60079-6:2015.
The following dates are fixed:
(dop) 2016-06-11
• latest date by which the document has
to be implemented at national level by
publication of an identical national
standard or by endorsement
(dow) 2018-03-27
• latest date by which the national
standards conflicting with the
document have to be withdrawn
This document supersedes EN 60079-6:2007.

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. CENELEC [and/or CEN] shall not be held responsible for identifying any or all such

patent rights.
This document has been prepared under a mandate given to CENELEC by the European

Commission and the European Free Trade Association, and supports essential requirements of EU

Directive(s).

For the relationship with EU Directive(s) see informative Annex ZZ, which is an integral part of this

document.
Endorsement notice

The text of the International Standard IEC 60079-6:2015 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 series NOTE Harmonized in the series EN 60079.
IEC 62770 NOTE Harmonized as EN 62770.
---------------------- Page: 4 ----------------------
SIST EN 60079-6:2016
EN 60079-6:2015 (E)
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications

The following documents, in whole or in part, are normatively referenced in this document and are

indispensable for its application. For dated references, only the edition cited applies. For undated

references, the latest edition of the referenced document (including any amendments) applies.

NOTE 1 When an International Publication has been modified by common modifications, indicated by (mod), the relevant

EN/HD applies.

NOTE 2 Up-to-date information on the latest versions of the European Standards listed in this annex is available here:

www.cenelec.eu.
Publication Year Title EN/HD Year
IEC 60079-0 - Explosive atmospheres -- Part 0: EN 60079-0 -
Equipment - General requirements
IEC 60156 - Insulating liquids - Determination of the EN 60156 -
breakdown voltage at power frequency -
Test method
IEC 60247 - Insulating liquids - Measurement of relative EN 60247 -
permittivity, dielectric dissipation factor (tan
d) and d.c. resistivity
IEC 60296 - Fluids for electrotechnical applications - EN 60296 -
Unused mineral insulating oils for
transformers and switchgear
IEC 60529 - Degrees of protection provided by - -
enclosures (IP Code)
IEC 60814 - Insulating liquids - Oil-impregnated paper EN 60814 -
and pressboard - Determination of water
by automatic coulometric Karl Fischer
titration
IEC 60836 - Specifications for unused silicone EN 60836 -
insulating liquids for electrotechnical
purposes
IEC 61099 - Insulating liquids - Specifications for EN 61099 -
unused synthetic organic esters for
electrical purposes
IEC 61125 - EN 61125 -
IEC 62021-1 - Insulating liquids - Determination of acidity EN 62021-1 -
-- Part 1: Automatic potentiometric titration
IEC 62535 - Insulating liquids - Test method for EN 62535 -
detection of potentially corrosive sulphur in
used and unused insulating oil
ISO 2592 - Determination of flash and fire points - EN ISO 2592 -
Cleveland open cup method
ISO 2719 - Determination of flash point - Pensky- EN ISO 2719 -
Martens closed cup method
ISO 3016 - Petroleum products - Determination of - -
pour point
---------------------- Page: 5 ----------------------
SIST EN 60079-6:2016
EN 60079-6:2015 (E)
ISO 3104 - Petroleum products - Transparent and EN ISO 3104 -
opaque liquids - Determination of
kinematic viscosity and calculation of
dynamic viscosity
---------------------- Page: 6 ----------------------
SIST EN 60079-6:2016
EN 60079-6:2015 (E)
Annex ZZ
(informative)
Relationship between this European standard and the essential requirements of
Directive 94/9/EC aimed to be covered

This European standard has been prepared under a Commission’s standardisation request to provide

one voluntary means of conforming to essential of Directive 94/9/EC of the European Parliament and

the Council of 23 March 1994 on the approximation of the laws of the Member States concerning

equipment and protective systems intended for use in potentially explosive atmospheres.

Once this standard is cited in the Official Journal of the European Union under that Directive,

compliance with the normative clauses of this standard given in Table ZZ.1 confers, within the limits of

the scope of this standard, a presumption of conformity with the corresponding essential requirements

of that Directive, and associated EFTA regulations.

Table ZZ.1 – Correspondence between this European standard and Annex II of Directive

94/9/EC
Essential Requirements of Clause(s) / sub-clause(s)
Remarks / Notes
Directive of this EN
1.0.1. 4, 5
1.0.2. 4
1.0.3. 7, 8
1.0.4. Not covered
1.0.5. 7
1.0.6. 8
1.1.1. 4, 5
1.1.2. 4, 5
1.1.3. 5
1.2.1. 4, 5
1.2.2. 4
1.2.3. Not covered
1.2.4. 4
1.2.5. Not covered
1.2.6. 4.5
1.2.7. Not covered
1.2.8. Not covered
---------------------- Page: 7 ----------------------
SIST EN 60079-6:2016
EN 60079-6:2015 (E)
1.2.9. Not covered
1.3.1. All Covered by the principle of the
type of protection "o":
Immersion of potential ignition
sources in oil.
1.3.2. 4.5
1.3.3. Not covered
1.3.4. Not covered
1.3.5. Not covered
1.4.1. 4
1.4.2. 4
1.5.1 4.5, 4.6, 4.7
1.5.2. Not covered
1.5.3. Not covered
1.5.4. 4.6, 4.7
1.5.5. 4.6, 4.7
1.5.6. Not covered
1.5.7. Not covered
1.5.8. Not covered
1.6.1. Not covered
1.6.2. Not covered
1.6.3. Not covered
1.6.4. 4.9
1.6.5. Not covered
2.0.1.1. 4, 5
2.0.1.2. 4.5
2.0.1.3. 4.8
2.0.1.4. Not covered
2.0.2.1. 4.1, 4.8
2.0.2.2. 4.5
---------------------- Page: 8 ----------------------
SIST EN 60079-6:2016
EN 60079-6:2015 (E)
2.0.2.3 4.5 and
2.1.1.1. 4, 5
2.1.1.2. 4.8
2.1.1.3. 4.5
2.1.2.1. 4, 5
2.1.2.2. Not covered
2.1.2.3. Not covered
2.2.1.1. 4.1, 4.2.2, 4.5
2.2.1.2. 4.8
2.2.1.3. 4.5 and
2.2.2.1 4.1, 4.2.2, 4.5
2.2.2.2. Not covered
2.2.2.3. Not covered
2.2.2.4. Not covered
2.3.1.1. 4.1, 4.2.3, 4.5
2.3.1.2. 4.8
2.3.2.1. 4.1, 4.2.3, 4.5
2.3.2.2. 4.8
2.3.2.3. Not covered
3.0.1. Not covered
3.0.2. Not covered
3.0.3. Not covered
3.0.4. Not covered
3.1.1. Not covered
3.1.2. Not covered
3.1.3. Not covered
3.1.4. Not covered
3.1.5. Not covered
---------------------- Page: 9 ----------------------
SIST EN 60079-6:2016
EN 60079-6:2015 (E)
3.1.6. Not covered
3.1.7. Not covered
3.1.8. Not covered

WARNING 1: Presumption of conformity stays valid only as long as a reference to this European

standard is maintained in the list published in the Official Journal of the European Union. Users of this

standard should consult frequently the latest list published in the Official Journal of the European

Union.

WARNING 2: Other Union legislation may be applicable to the product falling within the scope of this

standard.
---------------------- Page: 10 ----------------------
SIST EN 60079-6:2016
IEC 60079-6
Edition 4.0 2015-02
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Explosive atmospheres –
Part 6: Equipment protection by liquid immersion "o"
Atmosphères explosives –
Partie 6: Protection du matériel par immersion dans le liquide "o"
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 29.260.20 ISBN 978-2-8322-2251-5

Warning! Make sure that you obtained this publication from an authorized distributor.

Attention! Veuillez vous assurer que vous avez obtenu cette publication via un distributeur agréé.

® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale
---------------------- Page: 11 ----------------------
SIST EN 60079-6:2016
– 2 – IEC 60079-6:2015 © IEC 2015
CONTENTS

FOREWORD ......................................................................................................................... 4

1 Scope ............................................................................................................................ 6

2 Normative references..................................................................................................... 6

3 Terms and definitions .................................................................................................... 7

4 Constructional requirements .......................................................................................... 8

4.1 General ................................................................................................................. 8

4.2 Levels of protection and requirements of electrical equipment ................................ 8

4.2.1 Level of Protection ......................................................................................... 8

4.2.2 Requirements for Level of Protection “ob” ....................................................... 9

4.2.3 Requirements for Level of Protection “oc” ....................................................... 9

4.3 Switching device ................................................................................................... 9

4.4 Creepage and clearance ....................................................................................... 9

4.5 Liquid containment enclosures............................................................................. 10

4.5.1 General ....................................................................................................... 10

4.5.2 Sealed enclosures ....................................................................................... 10

4.5.3 Unsealed enclosures .................................................................................... 10

4.5.4 Outlet of breathing device or pressure relief device ....................................... 10

4.5.5 Enclosures intended to be opened ................................................................ 10

4.5.6 Determination of the maximum/minimum criteria of the protective liquid ........ 10

4.6 Immersion depth ................................................................................................. 11

4.7 Protective liquid level indication ........................................................................... 11

4.7.1 General ....................................................................................................... 11

4.7.2 Remote-indicating protective liquid level indicator ......................................... 12

4.7.3 Safety devices for Level of Protection “ob” .................................................... 12

4.8 Temperature limitations ....................................................................................... 12

4.8.1 General ....................................................................................................... 12

4.8.2 Maximum Surface Temperature .................................................................... 12

4.8.3 Flashpoint of the protective liquid ................................................................. 12

4.9 Field wiring connections to liquid immersion equipment ........................................ 12

4.10 Constructional elements of enclosures ................................................................ 12

4.10.1 Operating rods, shafts etc. ........................................................................... 12

4.10.2 Devices for draining of liquid ........................................................................ 13

5 Protective Liquid .......................................................................................................... 13

5.1 Protective liquid specification .............................................................................. 13

5.2 Detailed alternative specification ......................................................................... 13

5.3 Group I equipment .............................................................................................. 13

5.4 Liquid contamination and gassing that may result from arcing .............................. 13

5.5 Total volume of the protective liquid..................................................................... 14

6 Verifications and tests ................................................................................................. 14

6.1 Type tests ........................................................................................................... 14

6.1.1 Overpressure test on sealed enclosures ....................................................... 14

6.1.2 Reduced pressure test on sealed enclosures ................................................ 14

6.1.3 Overpressure test on unsealed enclosures ................................................... 14

6.1.4 Maximum temperature .................................................................................. 14

6.1.5 Switching Tests ............................................................................................ 15

6.2 Routine tests ....................................................................................................... 15

---------------------- Page: 12 ----------------------
SIST EN 60079-6:2016
IEC 60079-6:2015 © IEC 2015 – 3 –

6.2.1 Sealed enclosures ....................................................................................... 15

6.2.2 Unsealed enclosures .................................................................................... 15

7 Marking ....................................................................................................................... 15

8 Instructions.................................................................................................................. 16

Annex A (normative) Selection and erection requirements .................................................. 17

Annex B (normative) Maintenance requirements ................................................................. 18

Annex C (normative) Repair and Overhaul requirements ..................................................... 19

Bibliography ....................................................................................................................... 20

Table 1 – Working voltage ..................................................................................................... 9

Table 2 – Depth of immersion ............................................................................................. 11

Table B.1 – Inspection requirements ................................................................................... 18

---------------------- Page: 13 ----------------------
SIST EN 60079-6:2016
– 4 – IEC 60079-6:2015 © IEC 2015
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
EXPLOSIVE ATMOSPHERES –
Part 6: Equipment protection by liquid immersion "o"
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) 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 60079-6 has been prepared by IEC technical committee 31:

Equipment for explosive atmospheres.

This fourth edition cancels and replaces the third edition, published in 2007. This edition

constitutes a technical revision.
The significant changes with respect to the previous edition are listed below:

– Edition 4 represents a major technical revision of the requirements for oil immersion “o”

and should be considered as introducing all new requirements. The normal “Table of

Significant Changes” has not been included for this reason. In particular:

• The requirements for oil immersion “o” have been redefined into liquid immersion ,

levels of protection “ob” and “oc” as recommended by the responses to 31/715/DC
• The ability to protect sparking contacts has been added to both “ob” and “oc”
– Additional requirements have been introduced for the protective liquid.
---------------------- Page: 14 ----------------------
SIST EN 60079-6:2016
IEC 60079-6:2015 © IEC 2015 – 5 –

This part of IEC 60079 is to be used in conjunction with IEC 60079-0, Explosive atmospheres

– Part 0: Equipment – General requirements.
The text of this standard is based on the following documents:
FDIS Report on voting
31/1157/FDIS 31/1172/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 in the IEC 60079 series, under the general title Explosive atmospheres, can

be found on the IEC website.

The committee has decided that the contents of this publication will remain unchanged until

the stability date indicated on the IEC website 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.
---------------------- Page: 15 ----------------------
SIST EN 60079-6:2016
– 6 – IEC 60079-6:2015 © IEC 2015
EXPLOSIVE ATMOSPHERES –
Part 6: Equipment protection by liquid immersion "o"
1 Scope

This part of IEC 60079 specifies the requirements for the design, construction, testing and

marking of Ex Equipment and Ex Components with type of protection liquid immersion “o”

intended for use in explosive gas atmospheres.

Ex Equipment and Ex Components of type of protection liquid immersion “o” are either:

• Level of Protection “ob” (EPL “Mb” or “Gb”)
• Level of Protection “oc” (EPL “Gc”)

For Level of Protection “ob”, this standard applies where the rated voltage does not exceed

11 kV r.m.s. a.c. or d.c.

For Level of Protection “oc”, this standard applies where the rated voltage does not exceed

15 kV r.m.s. a.c. or d.c.
NOTE Requirements for higher voltages are under consideration.

This standard supplements and modifies the general requirements of IEC 60079-0. Where a

requirement of this standard conflicts with a requirement of IEC 60079-0, the requirement of

this standard takes precedence.
2 Normative references

The following documents, in whole or in part, are normatively referenced in this document and

are indispensable for its application. 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, Explosive Atmospheres – Part 0: Equipment – General requirements

IEC 60156, Insulating liquids – Determination of the breakdown voltage at power frequency –

Test method

IEC 60247, Insulating liquids – Measurement of relative permittivity, dielectric dissipation

factor (tan δ) and d.c. resistivity

IEC 60296, Fluids for electrotechnical applications – Unused mineral insulating oils for

transformers and switchgear
IEC 60529, Degrees of protection provided by enclosures (IP Code)

IEC 60814, Insulating liquids – Oil impregnated paper and pressboard – Determination of

water by automatic coulometric Karl Fischer titration

IEC 60836, Specifications for unused silicone insulating liquids for electrotechnical purposes

---------------------- Page: 16 ----------------------
SIST EN 60079-6:2016
IEC 60079-6:2015 © IEC 2015 – 7 –

IEC 61099, Insulating liquids – Specifications for unused synthetic organic esters for electrical

purposes

IEC 61125, Unused hydrocarbon based insulating liquids – Test methods for evaluating the

oxidation stability

IEC 62021-1, Insulating liquids – Determination of acidity – Part 1: Automatic potentiometric

titration

IEC 62535, Insulating liquids – Test method for detection of potentially corrosive sulphur in

used and unused insulating oil
ISO 2592, Determination of flash and fire points – Cleveland open cup method
ISO 2719, Determination of flash point – Pensky-Martens closed cup method
ISO 3016, Petroleum oils – Determination of pour point

ISO 3104, Petroleum products – Transparent and opaque liquids – Determination of kinematic

viscosity and calculation of dynamic viscosity
3 Terms and definitions

For the purposes of this document, the terms and definitions given in IEC 60079-0 and the

following apply.
3.1
liquid immersion "o"

type of protection in which the electrical equipment or parts of the electrical equipment are

immersed in a protective liquid in such a way that an explosive gas atmosphere which may be

above the liquid or outside the enclosure cannot be ignited
3.2
protective liquid

liquid which prevents the explosive atmosphere from making direct contact with potential

ignition sources
3.3
sealed equipment

equipment designed and constructed in such a manner as to prevent ingress of an external

atmosphere during the expansion and contraction of the internally contained liquid during

normal operation, for example, by means of an expansion vessel
3.4
non-sealed equipment

equipment designed and constructed in such a manner as to allow the ingress and egress of

an external atmosphere during the expansion and contraction of the internally contained fluid

during normal operation
3.5
maximum permissible protective liquid level

maximum level that the protective liquid can attain in normal service, taking into account the

effects of expansion from the worst-case filling condition specified by the manufacturer to the

condition of full load at maximum ambient temperature for which the equipment is designed

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SIST EN 60079-6:2016
– 8 – IEC 60079-6:2015 © IEC 2015
3.6
minimum permissible protective liquid level

minimum level that the protective liquid can attain in normal service taking into account the

effects of contraction from the worst-case filling condition to the condition of de-energization

at minimum ambient temperature
3.7
disconnector

mechanical switching device which provides, in the open position, an isolating distance in

accordance with specified requirements

Note 1 to entry: A disconnector is capable of opening and closing a circuit when either negligible current is

broken or made, or when no significant change in the voltage across the terminals of each of the poles of the

disconnector occurs. It is also capable of carrying currents under normal circuit conditions and carrying for a

specified time currents under abnormal conditions such as those of short circuit.

[SOURCE: IEC 60050-441:1984, 441-14-05]
3.8
switching device
device designed to make or break the current in one or more electric circuits
[SOURCE: IEC 60050-441:1984, 441-14-01]
3.9
safety device

device intended for use inside or outside explosive atmospheres but required for or

contributing to the safe functioning of equipment and protective systems with respect to the

risks of explosion
3.10
tap selector

device designed to carry, but not to make or break current, used in conjunction with a diverter

switch to se
...

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