EN 60079-6:2015/A1:2024

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

NEXT ACTION: UNDER BT CONSULTATION SOON (finalization EN with revised Annex Z)
HAS CONSULTANT PUB ASSESSMENT BY 2020-09-24 -- non compliant assessment received
20200325: consultant assessment missing and Annex ZZ was not circulated at FV; document blocked until such a time as this can be resolved

Explosionsgefährdete Bereiche - Teil 6: Geräteschutz durch Flüssigkeitskapselung "o"

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

Eksplozivne atmosfere - 6. del: Zaščita opreme s potopitvijo v tekočino "o" (IEC 60079-6:2015/A1:2020)

General Information

• Status: Published
• Publication Date: 05-Dec-2024
• Withdrawal Date: 01-Dec-2020
• ICS: 29.260.20 - Electrical apparatus for explosive atmospheres
• Technical Committee: CLC/TC 31 - Electrical apparatus for explosive atmospheres - General requirements
• Drafting Committee: IEC/TC 31 - Electrical apparatus for potentially explosive atmospheres
• Current Stage: 6060 - Document made available - Publishing
• Start Date: 06-Dec-2024
• Completion Date: 06-Dec-2024
• 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/BC/CEN/92/46 - Standardization mandate assigned to CEN/CENELEC concerning equipment and protective systems intended for use in potentially explosive atmospheres
• Ref Project: SIST EN 60079-6:2016/A1:2025 - Explosive atmospheres - Part 6: Equipment protection by liquid immersion "o" (IEC 60079-6:2015/A1:2020)

Relations

• Amends: EN 60079-6:2015 - Explosive atmospheres - Part 6: Equipment protection by liquid immersion "o"
• Effective Date: 27-Jan-2023

Overview

EN 60079-6:2015/A1:2024 is the CENELEC amendment to the IEC standard for equipment protection by liquid immersion "o" in explosive atmospheres. Approved as a European Standard in 2024, this amendment supplements EN 60079-6:2015 with additional requirements - notably Annex D - addressing Level of Protection "oc" for higher-voltage liquid‑immersed equipment. The document highlights implementation timelines, national adoption rules and cross-references to related IEC standards.

Note: national implementation and revision tasks (Annex Z/ZZ) and consultant assessments have been recorded during finalisation; stakeholders should check CENELEC national committees for the latest status and circulation notes.

Key Topics

• Scope extension (Annex D): Adds supplementary requirements for Level of Protection "oc" where rated voltages exceed 15 kV and up to 245 kV AC or DC. Targets liquid‑immersed transformers, reactors, tap‑changers, swivels and other HV liquid‑insulated equipment.

• Safety devices and automatic disconnection: Each liquid‑filled compartment must have dedicated safety devices and a pressure relief arrangement that triggers automatic power disconnection. If the relief outlet is not downward‑directed, a guide system (e.g. pipe) is required.

• Protective liquids: In addition to liquids already listed in the base standard, natural ester insulating liquids complying with IEC 62770 may be used for higher‑voltage equipment (proven up to 245 kV within ambient temperature limits).

• Immersion depth and verification: Minimum immersion depths shall be specified by the manufacturer and verified by high‑voltage tests performed at the minimum liquid level.

• Connections and cable requirements: Field wiring >15 kV must be shielded and armoured to mitigate external arcs; terminations may employ other Types of Protection (e.g. "d", "p", "s") with applicable overpressure or enclosure tests. When bushings are used, IEC 60137 requirements apply.

• On‑load tap‑changers (OLTC): OLTCs shall not produce arcs or sparks during switching; DC switching is not permitted. Vacuum tap changers are noted as an arc‑free solution.

• Containment and sealing: Sealed liquid containment designs are required for HV liquid‑insulated equipment; unsealed enclosures are not permitted for the higher‑voltage applications covered by Annex D.

• Routine testing: Dielectric and partial discharge tests reference IEC 60076‑3 and IEC 60071. Routine phase‑to‑earth and phase‑to‑phase tests apply to all equipment; additional tests (partial discharge, lightning impulse) apply above specified voltage levels.

Applications

This amendment is directly relevant to designers, manufacturers and operators of high‑voltage liquid‑immersed equipment used in hazardous (explosive) atmospheres, including:

• Oil‑ or ester‑immersed transformers and reactors
• Offshore HV swivels and power regulators
• Tap‑changers, earthing and switching resistors in HV systems
• Installations where transmission distances require voltages up to 245 kV

Practical benefits include clarified safety device requirements, validated liquid options (natural esters), and prescriptive test/verification methods to reduce ignition risk in explosive atmospheres.

Related Standards

• IEC 60079‑6 / EN 60079‑6 (base standard)
• IEC 60076‑3 (Power transformers - insulation levels and dielectric tests)
• IEC 60071 series (Insulation co‑ordination)
• IEC 60079‑1, IEC 60079‑2, IEC 60079‑33 (other Types of Protection)
• IEC 60137 (Insulated bushings)
• IEC 62770 (Natural ester fluids)
• IEC 61936‑1 (recommended high‑voltage installation rules)

For implementation, consult the CENELEC national committee and the official EN publication for mandatory national forewords, dates for national adoption, and any pending consultation or annex modifications.

Standards Content (Sample)

SLOVENSKI STANDARD
01-maj-2025
Eksplozivne atmosfere - 6. del: Zaščita opreme s potopitvijo v tekočino "o" (IEC
60079-6:2015/A1:2020)
Explosive atmospheres - Part 6: Equipment protection by liquid immersion "o" (IEC
60079-6:2015/A1:2020)
Explosionsgefährdete Bereiche - Teil 6: Geräteschutz durch Flüssigkeitskapselung "o"
(IEC 60079-6:2015/A1:2020)
Atmosphères explosives - Partie 6: Protection du matériel par immersion dans le liquide
"o" (IEC 60079-6:2015/A1:2020)
Ta slovenski standard je istoveten z: EN 60079-6:2015/A1:2024
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.

EUROPEAN STANDARD EN 60079-6:2015/A1

NORME EUROPÉENNE
EUROPÄISCHE NORM December 2024
ICS 29.260.20
English Version
Explosive atmospheres - Part 6: Equipment protection by liquid
immersion "o"
(IEC 60079-6:2015/A1:2020)
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/A1:2020) (IEC 60079-6:2015/A1:2020)
This amendment A1 modifies the European Standard EN 60079-6:2015; it was approved by CENELEC on 2020-03-30. CENELEC
members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this amendment 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 amendment 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, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the
Netherlands, Norway, Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Türkiye and the United Kingdom.

European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2024 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN 60079-6:2015/A1:2024 E

European foreword
The text of document 31/1517/FDIS, future edition 4 of IEC 60079-6/A1, prepared by TC 31
"Equipment for explosive atmospheres" was submitted to the IEC-CENELEC parallel vote and
approved by CENELEC as EN 60079-6:2015/A1:2024.
The following dates are fixed:
• latest date by which the document has to be implemented at national (dop) 2025-12-31
level by publication of an identical national standard or by endorsement
• latest date by which the national standards conflicting with the (dow) 2027-12-31
document have to be withdrawn
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CENELEC shall not be held responsible for identifying any or all such patent rights.
Any feedback and questions on this document should be directed to the users’ national committee. A
complete listing of these bodies can be found on the CENELEC website.
Endorsement notice
The text of the International Standard IEC 60079-6:2015/A1:2020 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 standard indicated:
IEC 60214 series NOTE Approved as EN 60214 series
IEC 61936-1 NOTE Approved as EN IEC 61936-1
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements 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 1  Where 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.cencenelec.eu.
Add the following references:
Publication Year Title EN/HD Year
IEC 60071 series Insulation co-ordination EN IEC 60071 series
IEC 60076-3 - Power transformers - Part 3: Insulation EN 60076-3 -
levels, dielectric tests and external
clearances in air
IEC 60079-1 - Explosive atmospheres - Part 1: EN 60079-1 -
Equipment protection by flameproof
enclosures "d"
IEC 60079-2 - Explosive atmospheres - Part 2: EN 60079-2 -
Equipment protection by pressurized
enclosure "p"
IEC 60079-33 - Explosive atmospheres - Part 33: CLC/TR 60079-33 -
Equipment protection by special protection
's'
IEC 60137 - Insulated bushings for alternating voltages EN 60137 -
above 1000 V
IEC 62770 - Fluids for electrotechnical applications - EN IEC 62770 -
Unused natural esters for transformers and
similar electrical equipment
IEC 60079-6 ®
Edition 4.0 2020-02
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
A MENDMENT 1
AM ENDEMENT 1
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 978-2-8322-7866-6

– 2 – IEC 60079-6:2015/AMD1:2020
 IEC 2020
FOREWORD
This amendment has been prepared by IEC technical committee 31: Equipment for explosive
atmospheres.
The text of this amendment is based on the following documents:
FDIS Report on voting
31/1517/FDIS 31/1526/RVD
Full information on the voting for the approval of this amendment can be found in the report
on voting indicated in the above table.
The committee has decided that the contents of this amendment and the base 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.
_____________
1 Scope
Delete the Note.
Add, after the fourth paragraph of Clause 1, the following new text:
Additionally, for Level of Protection "oc", Annex D applies where the rated voltage exceeds
15 kV AC RMS or DC and up to 245 kV AC RMS or DC.
Annex D applies specifically to liquid immersed transformers and reactors, and other liquid
immersed equipment such as swivels for off-shore platforms, power regulators, tap changers
and earthing/switching resistors.
2 Normative references
Add the following new references:
IEC 60071 (all parts), Insulation co-ordination
IEC 60076-3, Power transformers – Part 3: Insulation levels, dielectric tests and external
clearances in air
IEC 60079-1, Explosive atmospheres – Part 1: Equipment protection by flameproo
...