EN 50068:2018

SLOVENSKI STANDARD
01-februar-2018
1DGRPHãþD
SIST EN 50068:1995
SIST EN 50068:2015
Visokonapetostne stikalne in krmilne naprave - S plinom polnjena ohišja iz
gnetljivega jekla
High-voltage switchgear and controlgear - Gas-filled wrought steel enclosures
Hochspannungs-Schaltgeräte und Schaltanlagen - Gasgefüllte Kapselungen aus
Schmiedestahl
Appareillage électrique haute tension - Enveloppes sous pression en acier corroyé et en
alliage d´acier
Ta slovenski standard je istoveten z: EN 50068:2018
ICS:
29.130.10 Visokonapetostne stikalne in High voltage switchgear and
krmilne naprave controlgear
77.080.20 Jekla Steels
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD EN 50068
NORME EUROPÉENNE
EUROPÄISCHE NORM
November 2018
ICS 29.130.10 Supersedes EN 50068:1991
English Version
High-Voltage Switchgear and Controlgear - Gas-filled wrought
steel enclosures
Appareillage électrique haute tension - Enveloppes sous Hochspannungs-Schaltgeräte und Schaltanlagen -
pression en acier corroyé et en alliage d'acier Gasgefüllte Kapselungen aus Schmiedestahl
This European Standard was approved by CENELEC on 2018-08-27. 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, Serbia, 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: Rue de la Science 23, B-1040 Brussels
© 2018 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN 50068:2018 E
Contents Page
European foreword .4
Introduction .5
1 Scope .6
2 Normative references .6
3 Terms and definitions .7
4 Quality assurance .9
5 Normal and special service conditions .9
6 Materials . 10
7 Design . 10
7.1 General . 10
7.2 Calculation methods . 10
7.2.1 General . 10
7.2.2 Evaluation of mechanical strength using “Design by Formula” . 11
7.2.3 Evaluation of mechanical strength using “Design by Analysis” . 11
7.2.4 Evaluation of mechanical strength using “Design by Burst test” . 12
7.2.5 Flanges . 14
7.2.6 Bolted connections . 14
7.3 Inspection and access openings . 15
8 Manufacture and workmanship . 15
8.1 Material identification . 15
8.2 Order of completion of weld seams . 15
8.3 Cutting of materials . 15
8.4 Forming of shell sections and end plates . 15
8.5 Assembly tolerances . 15
8.6 Welded joints . 15
8.7 Assembly for welding. 16
8.8 General welding requirements . 16
8.9 Preheating . 16
8.10 Surface finish . 16
9 Repair of welding defects . 16
10 Inspection, testing and certification . 17
10.1 Type tests . 17
10.1.1 General . 17
10.1.2 Burst test procedure . 17
10.1.3 Strain measurement test . 17
10.2 Inspection and routine tests . 17
10.2.1 General . 17
10.2.2 Routine pressure tests . 18
10.3 Welding procedure specifications . 18
10.4 Welder performance tests . 18
10.5 Non-destructive testing . 18
10.5.1 Amount of testing of welded joints . 18
10.5.2 Test methods for weld seams . 19
10.5.3 Surface conditions and preparations for testing . 19
10.5.4 Marking of the enclosure welds . 20
10.5.5 Reporting . 20
10.5.6 Minimum acceptance levels . 20
10.5.7 Assessment of imperfections . 20
10.6 Design specification, drawings and data sheets . 22
10.7 Certificate . 22
10.8 Stamping . 22
10.9 Final inspection . 22
11 Pressure relief devices . 23
11.1 General . 23
11.2 Bursting discs . 23
11.3 Self-closing pressure relief valves . 23
11.4 Non-self-closing pressure relief devices . 23
Annex A (informative) A-deviations . 25
Bibliography . 26

European foreword
This document (EN 50068:2018) has been prepared by CLC/TC 17AC, “High-voltage switchgear and
controlgear”.
The following dates are fixed:
• latest date by which this document has (dop) 2019-08-27
to be implemented at national level by
publication of an identical national
standard or by endorsement
• latest date by which the national (dow) 2021-08-27
standards conflicting with this 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.
This document supersedes EN 50068:1991, EN 50068:1991/corrigendum Aug. 2007 and
EN 50068:1991/A1:1993.
This document has been revised by CENELEC Technical Committee 17AC “High-voltage switchgear and
controlgear”. It supplements the relevant product standards on gas-insulated switchgear and controlgear in
that it provides specific requirements for pressurized high-voltage switchgear and controlgear.
The present document has been written to get a European specification for the design, construction, testing,
inspection and certification of pressurized enclosures used in high-voltage switchgear and controlgear.
In this respect, this document constitutes the exclusion of HV switchgear from the scope of the Directive
2014/68/EU (superseding 97/23/EC) concerning pressure equipment. Article 1, 2. (l) excludes “enclosures
for high-voltage electrical equipment such as switchgear, controlgear, transformers, and rotating machines”
from the scope of the Directive.
This document deals with gas-insulated switchgear enclosures of wrought steel and their welding. For
different enclosure materials, other European Standards are available.
Introduction
This document covers the requirements for the design, construction, testing, inspection and certification of
gas-filled enclosures for use specifically in high-voltage switchgear and controlgear, or for associated gas-
filled equipment.
Special consideration is given to these enclosures for the following reasons.
(a) The enclosures usually form the containment of electrical equipment, thus their shape is determined by
electrical rather than mechanical requirements.
(b) The enclosures are installed in restricted access areas and the equipment is operated by instructed,
authorized persons only.
(c) As the thorough drying of the inert, non-corrosive gas-filling medium is fundamental to the satisfactory
operation of the electrical equipment, the gas is periodically checked. For this reason, no internal corrosion
allowance is required on the wall thickness of these enclosures.
(d) The enclosures are subjected to only small fluctuations o
...