EN 50243:2022

SLOVENSKI STANDARD
01-oktober-2022
Nadomešča:
SIST EN 50243:2004
Skoznjiki za zunanjo montažo 24 kV in 36 kV ter za 5 kA in 8 kA, za
transformatorje, napolnjene s tekočino
Outdoor bushings for 24 kV and 36 kV and for 5 kA and 8 kA, for liquid filled transformers
Durchführungen für Freiluft, 24 kV und 36 kV sowie 5 kA und 8 kA, für flüssigkeitsgefüllte
Transformatoren
Traversées d'extérieur pour 24 kV et 36 kV et pour 5 kA et 8 kA, pour transformateurs
remplis de liquide
Ta slovenski standard je istoveten z: EN 50243:2022
ICS:
29.080.20 Skoznjiki Bushings
29.180 Transformatorji. Dušilke Transformers. Reactors
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD EN 50243
NORME EUROPÉENNE
EUROPÄISCHE NORM August 2022
ICS 29.080.20; 29.180 Supersedes EN 50243:2002
English Version
Outdoor bushings for 24 kV and 36 kV and for 5 kA and 8 kA, for
liquid filled transformers
Traversées d'extérieur pour 24 kV et 36 kV et pour 5 kA et Durchführungen für Freiluft, 24 kV und 36 kV sowie 5 kA
8 kA, pour transformateurs remplis de liquide und 8 kA, für flüssigkeitsgefüllte Transformatoren
This European Standard was approved by CENELEC on 2022-06-20. 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, 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
© 2022 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN 50243:2022 E
Contents Page
European foreword . 3
1 Scope . 4
2 Normative references . 4
3 Terms and definitions . 5
4 Requirements . 5
4.1 General Requirements . 5
4.2 Ratings . 5
4.2.1 Standard values of highest voltage for equipment (Um) . 5
4.2.2 Standard values of rated current (I ) . 5
r
4.3 Common dimensions and creepage distances of bushings type A and type B . 5
4.4 Parts list according to bushing type A . 8
4.5 Parts list according to bushing type B . 9
Annex A (normative) Detail drawings of components . 10
A.1 General . 10
A.2 Insulator (Item N° 1) . 11
A.3 Conductor tube (Item N° 2) . 15
A.4 Upper cap (Item N° 4) . 16
A.5 Lower cap (Item N° 6) . 16
A.6 Nut (Item N° 3) . 17
A.7 Sealing ring (Item N° 5) . 18
A.8 Flat gasket (Item N° 9) . 18
A.9 Flat gasket (Item N° 18) . 18
A.10 Clamping ring (Item N° 16) . 19
A.11 Interlayer (Item N° 13) . 19
A.12 Compression ring (Item N° 11) . 20
A.13 Retaining ring (Item N° 12) . 21
A.14 Flat gasket (Item N° 10) . 21
A.15 Clamping paw (Item N° 17). 22
Annex B (normative) Vertical connecting flags . 23
B.1 General . 23
B.2 Vertical connecting flags – 5 000 A type TP78-120 . 23
B.3 Vertical connecting flags – 8 000 A – type TP78-180 . 24
Bibliography . 26

European foreword
This document (EN 50243:2022) has been prepared by CLC/TC 36A “Insulated bushings”.
The following dates are fixed:
• latest date by which this document has to be (dop) 2023-06-20
implemented at national level by publication of
an identical national standard or by
endorsement
• latest date by which the national standards (dow) 2025-06-20
conflicting with this document have to be
withdrawn
This document will supersede EN 50243:2002 and all of its amendments and corrigenda (if any).
— Addition of the highest pollution class.
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.
1 Scope
This document is applicable to ceramic insulated outdoor bushings for highest voltages for equipment of 24 kV
and 36 kV, with rated currents of 5 kA and 8 kA for insulating liquid filled transformers and frequencies from
15 Hz up to 60 Hz.
This document establishes dimensions to ensure interchangeability and adequate mounting of bushings.
Two types of construction are specified, type A and type B, both types for highest voltages for equipment
24 kV and 36 kV and rated currents of 5 kA and 8 kA. The mechanical stresses of the conductor tube define
the difference between type A and type B. The conductor tube of type A is axially and radially fixed in the top
of the bushing. The inner line terminal of the transformer can be flexible and without any special support for
the lower end of the conductor tube.
For new installations bushings of Type A are expected to be used. Type B bushings can be supplied at the
request of a customer.
In case of type B, the conductor tube is only radially fixed in the top of the bushing. In that case, a rigid
support is mounted to fix the lower end of the conductor tube (for example, in combination with a drip proofed
sealing end). The drip proofed sealing end is often required in the service requirements. In this case, it is not
possible to use type A because of the existing double fixation. Therefore, both bushing types A and B are
specified.
The condition for the usage of type B is that the drip-proof sealing end is able to withstand the mechanical
stress in axial direction.
2 Normative references
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.
EN 12165:2016, Copper and copper alloys — Wrought and unwrought forging stock
EN 60137, Insulated bushings for alternating voltages above 1 000 V (IEC 60137)
EN 60672-3, Ceramic and glass-insulating materials — Part 3: Specifications for individual materials (IEC
60672-3)
EN 62155, Hollow pressurized and unpressurized ceramic and glass insulators for use in electrical equipment
with rated voltages greater than 1 000 V (IEC 62155)
EN ISO 286-2, Geometrical product specifications (GPS) — ISO code system for tolerances on linear sizes —
Part 2: Tables of standard tolerance classes and limit deviations for holes and shafts (ISO 286-2)
EN ISO 1101, Geometrical product specifications (GPS) — Geometrical tolerancing — Tolerances of form,
orientation, location and run-out (ISO 1101)
EN ISO 21920-1, Geometrical product specifications (GPS) — Surface texture: Profile — Part 1: Indication of
surface texture (ISO 21920-1)
IEC/TS 60815 (all parts), Selection and dimensioning of high-voltage insulators intended for use in polluted
conditions
ISO 261, ISO general purpose metric screw threads — General plan
ISO 2768-1, General Tolerances — Part 1: Tolerances for linear and angular dimensions without individual
tolerance indications
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https://www.iso.org/obp
— IEC Electropedia: available at https://www.electropedia.org/
3.1
bushing type A
bushing with a conductor tube which is axially and radially fixed in the top of the bushing
3.2
bushing type B
bushing with a conductor tube which is only radially fixed in the top of the bushing
4 Requirements
4.1 General requirements
Bushings specified by this document shall be installed with the transformer side of the bushing fully immersed
in insulating liquid and the other end in air.
Bushings shall meet the requirements of EN 60137.
4.2 Ratings
4.2.1 Standard values of highest voltage for equipment (U )
m
The value of U of a bushing shall be chosen from the standard values of the highest voltage for transformers
m
given below in kilovolts:
24 - 36
4.2.2 Standard values of rated current (I )
r
The value I of a bushing shall be chosen from the standard values given below in amperes:
r
5 000 – 8 000
4.3 Common dimensions and creepage distances of bushings type A and type B
The common dimensions of bushings type A and type B shall be as specified in Figure 1 and Table 1.
The details of the components are given in Annex A.
The provisions for arcing horns should be made if required.
In case of environmental conditions, which do not require site pollution severity class “c” or more according to
IEC/TS 60815 (all parts), an insulator with a reduced creepage distance can be agreed between the
purchaser and the manufacturer without changing the common dimensions.
Table 1 — Common dimensions of bushings type A and type B
Designation U I Minimum Nominal Insulator Arcing l l d l l l
m r 1 2 5 3 4 5
Creepage Distance Type Distance
(for design (kV) (A) (mm) (mm) (mm) (mm) (mm) (mm)
(mm)
Type A or B) (mm)
Min Max Max
For pollution level
(IEC/TS 60815 (all
parts)
b c d e
24–5/P2 5000   24-P2 540 100
24 384 480 270 285 320 150 100
(CD
24–8/P2 8000 570 130
480 mm)
24–5/P4 5000 635 100
24 384 480 600 744
36-P2
24–8/P2 8000 665 130
380 285 415 175 125
(CD
36–5/P2 5000   635 100
744 mm)
36 576 720
36–8/
...