IEC 62391-2:2025

Fixed electric double-layer capacitors for use in electric and electronic equipment - Part 2: Sectional specification - Electric double-layer capacitors for power application

IEC 62391-2:2025 applies to electric double-layer capacitors for power application.
Electric double-layer capacitors for power are intended for applications that require discharge currents in the range from mA to A. The characteristics of the capacitors include such performance as relatively high capacitance and low internal resistance, which is applicable to Class 3 and Class 5 of the measurement classification specified in IEC 62391-1:2022.
The object of this document is to specify preferred ratings and characteristics and to select from IEC 62391-1:2022 the appropriate quality assessment procedures, tests and measuring methods and to give general performance requirements for this type of capacitor. Test severities and requirements specified in detail specifications referring to this document provide specific test severities and requirements of an equal or higher performance level.
The definition of power density and its calculating procedure can be found in Annex A.
This edition includes the following significant technical changes with respect to the previous edition:
a) the document has been completely restructured to comply with the ISO/IEC Directives, Part 2;
b) introduction of a new technical categorization for the test methods;
c) reorganization of the test methods have been according to these new categories;
d) revision of the tables, figures and references according to changes.

Condensateurs électriques fixes à double couche utilisés dans les équipements électriques et électroniques - Partie 2: Spécification intermédiaire - Condensateurs électriques à double couche pour application de puissance

L’IEC 62391-2:2025 s’applique aux condensateurs électriques à double couche pour application de puissance.
Les condensateurs électriques à double couche pour application de puissance sont destinés aux applications qui exigent des courants de décharge dans la gamme des milliampères aux ampères. Les caractéristiques des condensateurs incluent des performances comme une capacité relativement élevée et une faible résistance interne, ce qui concerne la classe 3 et à la classe 5 de la classification des mesures spécifiée dans l’IEC 62391-1:2022.
Le présent document a pour objet de spécifier les valeurs assignées et caractéristiques préférentielles, et de choisir, à partir de l’IEC 62391-1:2022, les procédures d’assurance de la qualité, essais et méthodes de mesure appropriés, et de donner les exigences de performances générales pour ce type de condensateur. Les sévérités d’essai et les exigences stipulées dans les spécifications particulières faisant référence au présent document constituent des sévérités d’essai et des exigences spécifiques, correspondant à un niveau de performances supérieur ou égal.
La définition de la densité de puissance et sa procédure de calcul peuvent être consultées à l’Annexe A.
Cette édition inclut les modifications techniques majeures suivantes par rapport à l’édition précédente:
a) la structure du document a été intégralement réétudiée afin de respecter les Directives ISO/IEC, Partie 2:
b) introduction d’une nouvelle classification technique pour les méthodes d’essai;
c) réorganisation des méthodes d’essai selon ces nouvelles catégories;
d) révision des tableaux, figures et références en fonction des modifications apportées.

General Information

• Status: Published
• Publication Date: 12-Feb-2025
• ICS: 31.060.10 - Fixed capacitors
• Technical Committee: TC 40 - Capacitors and resistors for electronic equipment
• Drafting Committee: MT 62391-2 - TC 40/MT 62391-2
• Current Stage: PPUB - Publication issued
• Start Date: 13-Feb-2025
• Completion Date: 21-Feb-2025

Relations

• Revises: IEC 62391-2:2006 - Fixed electric double-layer capacitors for use in electronic equipment - Part 2: Sectional specfication - Electric double layer capacitors for power application
• Effective Date: 05-Sep-2023

Standards Content (Sample)

IEC 62391-2 ®
Edition 2.0 2025-02
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Fixed electric double-layer capacitors for use in electric and electronic
equipment –
Part 2: Sectional specification – Electric double-layer capacitors for power
application
Condensateurs électriques fixes à double couche utilisés dans les
équipements électriques et électroniques –
Partie 2: Spécification intermédiaire – Condensateurs électriques à double
couche pour application de puissance
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IEC 62391-2 ®
Edition 2.0 2025-02
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Fixed electric double-layer capacitors for use in electric and electronic
equipment –
Part 2: Sectional specification – Electric double-layer capacitors for power
application
Condensateurs électriques fixes à double couche utilisés dans les
équipements électriques et électroniques –
Partie 2: Spécification intermédiaire – Condensateurs électriques à double
couche pour application de puissance
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 31.060.10 ISBN 978-2-8327-0153-9
– 2 – IEC 62391-2:2025 © IEC 2025
CONTENTS
FOREWORD . 5
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 8
4 Preferred ratings and characteristics . 8
4.1 Preferred characteristics . 8
4.2 Preferred values of ratings . 9
4.2.1 Nominal capacitance (C ) . 9
N
4.2.2 Tolerance on nominal capacitance . 9
4.2.3 Rated voltage (U ) . 9
R
4.2.4 Rated temperature . 9
4.2.5 Internal resistance . 9
5 Test and measurement procedures, and performance requirements . 9
5.1 General . 9
5.2 Preliminary drying . 9
5.3 Test conditions and measurement conditions . 9
5.4 Visual examination and check of dimensions . 10
5.4.1 General . 10
5.4.2 Visual examination . 10
5.4.3 Requirements . 10
5.5 Electrical tests . 10
5.5.1 Capacitance . 10
5.5.2 Internal resistance . 10
5.5.3 Leakage current . 11
5.6 Robustness of terminations . 11
5.6.1 General . 11
5.6.2 Initial measurement . 11
5.6.3 Final inspection, measurements and requirements. 11
5.7 Resistance to soldering heat . 11
5.7.1 General . 11
5.7.2 Initial measurement . 11
5.7.3 Conditions . 12
5.7.4 Final inspection, measurements and requirements. 12
5.8 Solderability . 12
5.8.1 General . 12
5.8.2 Final inspection, measurements and requirements. 12
5.9 Rapid change of temperature . 12
5.9.1 General . 12
5.9.2 Initial measurement . 12
5.9.3 Conditioning . 12
5.9.4 Final inspection, measurements and requirements. 12
5.10 Vibration . 13
5.10.1 General . 13
5.10.2 Initial measurement . 13
5.10.3 Test conditions . 13
5.10.4 Final inspection, measurements and requirements. 13

5.11 Maintain voltage. 13
5.11.1 General . 13
5.11.2 Test conditions . 13
5.11.3 Final inspection, measurements and requirements. 13
5.12 Storage at high temperature . 13
5.12.1 General . 13
5.12.2 Initial measurement . 13
5.12.3 Test conditions . 14
5.12.4 Final inspection, measurements and requirements. 14
5.13 Damp heat, steady state . 14
5.13.1 General . 14
5.13.2 Initial measurement . 14
5.13.3 Conditioning of test . 14
5.13.4 Final inspection, measurements and requirements. 14
5.14 Endurance . 14
5.14.1 General . 14
5.14.2 Initial measurement . 14
5.14.3 Test conditions . 14
5.14.4 Final inspection, measurements and requirements. 14
5.15 Characteristics at high and low temperature . 15
5.15.1 General . 15
5.15.2 Measurements and requirements . 15
5.16 Passive flammability (if applicable) . 15
5.16.1 General . 15
5.16.2 Requirements . 15
5.17 Pressure relief (if applicable) . 15
5.17.1 General . 15
5.17.2 Requirements . 15
6 Marking . 15
6.1 General . 15
6.2 Information for marking . 15
6.3 Marking on the capacitors . 16
6.4 Marking of the packaging . 16
6.5 Additional marking . 16
7 Information to be given in a detail specification . 16
7.1 General . 16
7.2 Outline drawing and dimensions . 16
7.3 Mounting . 17
7.4 Rating and characteristics . 17
7.4.1 General . 17
7.4.2 Nominal capacitance range . 17
7.4.3 Particular characteristics . 17
7.4.4 Soldering . 17
7.5 Marking . 17
8 Quality assessment procedures . 17
8.1 Primary stage of manufacture . 17
8.2 Structurally similar components . 17
8.3 Certified test records of released lots . 17
8.4 Qualification approval procedures . 18

– 4 – IEC 62391-2:2025 © IEC 2025
8.4.1 General . 18
8.4.2 Qualification approval on the basis of the fixed sample size procedures . 18
8.5 Quality conformance inspection . 23
8.5.1 Formation of inspection lots . 23
8.5.2 Test schedule . 23
8.5.3 Delayed delivery . 23
8.5.4 Assessment levels . 23
Annex A (informative) Calculation procedure for power density . 25
A.1 General . 25
A.2 Calculation procedure for power density . 25
A.2.1 Calculation method of power density per mass . 25
A.2.2 Calculation method of power density per volume . 25
Annex X (informative) Cross-references to IEC 62391-2:2006 . 27
Bibliography . 28

Figure A.1 – Voltage characteristics between capacitor terminals . 26

Table 1 – Fixed sample size test plan for qualification approval – Assessment level EZ . 19
Table 2 – Test schedule for qualification approval . 20
Table 3 – Lot-by-lot inspection . 24
Table 4 – Periodic test . 24
Table X.1 – Cross-references to the previous edition . 27

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
FIXED ELECTRIC DOUBLE-LAYER CAPACITORS
FOR USE IN ELECTRIC AND ELECTRONIC EQUIPMENT –

Part 2: Sectional specification –
Electric double-layer capacitors for power application

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
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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
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shall not be held responsible for identifying any or all such patent rights.
IEC 62391-2 has been prepared by IEC technical committee 40: Capacitors and resistors for
electronic equipment. It is an International Standard.
This International Standard is to be used in conjunction with IEC 62391-1:2022.
This second edition cancels and replaces the first edition published in 2006. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) the document has been completely restructured to comply with the ISO/IEC Directives,
Part 2;
– 6 – IEC 62391-2:2025 © IEC 2025
b) introduction of a new technical categorization for the test methods;
c) reorganization of the test methods according to these new categories;
d) revision of the tables, figures and references according to changes.
The text of this International Standard is based on the following documents:
Draft Report on voting
40/3193/FDIS 40/3199/RVD
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this International Standard is English.
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
described in greater detail at www.iec.ch/publications.
A list of all parts in the IEC 62391 series, published under the general title Fixed electric
double-layer capacitors for use in electric and electronic equipment, can be found on the IEC
website.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under webstore.iec.ch in the data related to the
specific document. At this date, the document will be
• reconfirmed,
• withdrawn, or
• revised.
FIXED ELECTRIC DOUBLE-LAYER CAPACITORS
FOR USE IN ELECTRIC AND ELECTRONIC EQUIPMENT –

Part 2: Sectional specification –
Electric double-layer capacitors for power application

1 Scope
This part of IEC 62391 applies to electric double-layer capacitors for power application.
Electric double-layer capacitors for power are intended for applications that require discharge
currents in the range from mA to A. The characteristics of the capacitors include such
performance as relatively high capacitance and low internal resistance, which is applicable to
Class 3 and Class 5 of the measurement classification specified in IEC 62391-1:2022.
The object of this document is to specify preferred ratings and characteristics and to select from
IEC 62391-1:2022 the appropriate quality assessment procedures, tests and measuring
methods and to give general performance requirements for this type of capacitor. Test severities
and requirements specified in detail specifications referring to this document provide specific
test severities and requirements of an equal or higher performance level.
The definition of power density and its calculating procedure can be found in Annex A.
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.
IEC 60068-2-6:2007, Environmental testing – Part 2-6: Tests – Test Fc: Vibration (sinusoidal)
IEC 60068-2-14:2023, Environmental testing – Part 2-14: Tests – Test N: Change of
temperature
IEC 60068-2-20:2021, Environmental testing – Part 2-20: Tests – Test Ta and Tb: Test methods
for solderability and resistance to soldering heat of devices with leads
IEC 60417, Graphical symbols for use on equipment, available at http://www.graphical-
symbols.info/equipment
IEC 61193-2:2007, Quality assessment systems – Part 2: Selection and use of sampling plans
for inspection of electronic components and packages
IEC 62391-1:2022, Fixed electric double-layer capacitors for use in electric and electronic
equipment – Part 1: Generic specification
IEC 62391-2-1:2006, Fixed electric double-layer capacitors for use in electronic equipment –
Part 2-1: Blank detail specification – Electric double-layer capacitors for power application –
Assessment level EZ
– 8 – IEC 62391-2:2025 © IEC 2025
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 62391-1 and the
following apply.
ISO and IEC maintain terminology databases for use in standardization at the following
addresses:
• IEC Electropedia: available at https://www.electropedia.org/
• ISO Online browsing platform: available at https://www.iso.org/obp
3.1
surface mount capacitor
capacitor whose small dimensions and nature or shape of terminations make it suitable for
surface mounting
3.2
electric double-layer capacitor for power application
capacitor with relatively high capacitance and low internal resistance characteristics
Note 1 to entry: Capacitors are intended for applications that require discharge currents in the range from milliamps
to amps and are applicable to Class 3 and Class 5 of the measurement classification specified in IEC 62391-1:2022.
3.3
power density
P
d
electric power that can be taken out per mass (W/kg) or volume (W/l) of a capacitor
Note 1 to entry: Refer to Annex A.
Note 2 to entry: The higher the power density is, the higher the current can be taken efficiently.
4 Preferred ratings and characteristics
4.1 Preferred characteristics
The values given in the detail specification should be selected from the following:
The surface mount capacitors covered by this document are classified into climatic categories
in accordance with the general rules given in IEC 60068-1:2013, Annex A.
The lower and upper category temperatures and the duration of the damp-heat, steady-state
test shall be chosen from the following unless otherwise agreed between the manufacturer and
the customer.
Lower category temperature: −25 °C or −40 °C
Upper category temperature: +60 °C or +70 °C
Duration of the damp-heat, steady-state test: 10 days
The severities of the cold and dry heat tests are the lower and upper category temperatures
respectively.
For the damp-heat steady-state test, the atmospheric conditions shall be as follows:
• temperature: 40 °C ± 2 °C;
• relative humidity: 93 % ± 3 %.

4.2 Preferred values of ratings
4.2.1 Nominal capacitance (C )
N
The nominal capacitance shall be expressed in farads (F) and agreed between the manufacturer
and the customer. Preferred values of rated capacitance are the values from the E24 series of
IEC 60063 and their decimal multiples.
4.2.2 Tolerance on nominal capacitance
The preferred values of tolerance on nominal capacitance are:
±20 % or −20 % / +80 %.
4.2.3 Rated voltage (U )
R
The rated voltage shall be as agreed between the manufacturer and the customer. The preferred
values of the rated direct voltages are the values of the R20 series of ISO 3 and their decimal
multiples.
4.2.4 Rated temperature
The rated temperature value is 60 °C or 70 °C, unless otherwise agreed between the
manufacturer and the customer.
4.2.5 Internal resistance
The internal resistance shall be as agreed between the manufacturer and the customer. The
internal resistance shall be measured with the DC resistance method. However, if a coefficient
can be obtained from both DC and AC resistance methods, the AC resistance method may be
used for measurement.
5 Test and measurement procedures, and performance requirements
5.1 General
Test severities and requirements specified in detail specifications and referring to this document
are of equal or higher performance level, because lower performance levels are not permitted.
This clause supplements information given in IEC 62391-1:2022, Clause 5 to Clause 10.
5.2 Preliminary drying
If specified in the detail specification, the conditions shall be as given in IEC 62391-1:2022, 5.3.
5.3 Test conditions and measurement conditions
Test conditions: IEC 62391-1:2022, 5.2.1 applies.
Measurement conditions: IEC 62391-1:2022, 5.2.2 applies.

– 10 – IEC 62391-2:2025 © IEC 2025
5.4 Visual examination and check of dimensions
5.4.1 General
IEC 62391-1:2022, 7.1, applies with the following details.
5.4.2 Visual examination
A visual examination shall be carried out with suitable equipment with approximately 10×
magnification and lighting appropriate to the specimen under test and the quality level required.
The operator should have available facilities for incident or transmitted illumination as well as
an appropriate measuring facility.
5.4.3 Requirements
The capacitors shall be examined to verify that the materials, design, construction, physical
dimensions and workmanship are in accordance with the applicable requirements given in the
detail specification.
5.5 Electrical tests
5.5.1 Capacitance
5.5.1.1 General
IEC 62391-1:2022, 6.1, applies with the following details:
5.5.1.2 Measurement conditions
The ambient temperature shall be 20 °C ± 2 °C.
The measurement shall be made under the conditions specified in IEC 62391-1:2022, 6.1.3.3.
5.5.1.3 Requirements
The capacitance shall correspond with the rated value taking into account the specified
tolerance.
5.5.2 Internal resistance
5.5.2.1 General
IEC 62391-1:2022, 6.1, applies with the following details.
The AC resistance method may be used when a correlation is found with the results of the DC
measurement method. The measurement method should be in accordance with
IEC 62391-1:2022, 6.2.2.
5.5.2.2 Measurement conditions
The ambient temperature shall be 20 °C ± 2 °C.
The measurement shall be made under the conditions specified in IEC 62391-1:2022, 6.1.3.3.
5.5.2.3 Requirements
The internal resistance shall meet the requirements of the detail specification.

5.5.3 Leakage current
5.5.3.1 General
IEC 62391-1:2022, 6.3, applies with the following details.
5.5.3.2 Measurement conditions
The ambient temperature shall be 20 °C ± 2 °C.
The rated voltage shall be applied across the capacitor and its protective resistor.
The protective resistor shall have a value of 1 000 Ω or less.
The discharge time before the test shall be at least 12 h, unless otherwise agreed between the
manufacturer and the customer.
The electrification time shall be 24 h unless otherwise agreed between the manufacturer and
the customer.
5.5.3.3 Requirements
The leakage current (at 20 °C ± 2 °C) shall meet the requirements of the detail specification.
5.6 Robustness of terminations
5.6.1 General
IEC 62391-1:2022, 7.2, applies with the following details.
The detail specification shall specify the test method and degree of severity to be used.
5.6.2 Initial measurement
The capacitance shall be measured in accordance with 5.5.1.
5.6.3 Final inspection, measurements and requirements
The capacitors shall be visually examined and shall meet the requirements shown in Table 2.
5.7 Resistance to soldering heat
5.7.1 General
IEC 62391-1:2022, 9.1, applies with the following details.
NOTE Not applicable to capacitors with screw terminations or other terminations not designed to be soldered, as
stated in the detail specification.
5.7.2 Initial measurement
The capacitance shall be measured in accordance with 5.5.1.

– 12 – IEC 62391-2:2025 © IEC 2025
5.7.3 Conditions
No pre-drying.
The capacitors shall be tested in accordance with IEC 60068-2-20:2021, 5.2, method 1 of
Test Tb.
Immersion time shall be 5 s ± 0,5 s.
5.7.4 Final inspection, measurements and requirements
The capacitors shall be visually examined, electrically measured and shall meet the
requirements shown in Table 2.
5.8 Solderability
5.8.1 General
IEC 62391-1:2022, 9.2, applies with the following details.
NOTE Not applicable to capacitors with screw terminations or other terminations not designed to be soldered, as
stated in the detail specification.
5.8.2 Final inspection, measurements and requirements
The capacitors shall be visually examined and shall meet the requirements shown in Table 2.
5.9 Rapid change of temperature
5.9.1 General
IEC 62391-1:2022, 8.1, applies with the following details.
5.9.2 Initial measurement
The capacitance shall be measured in accordance with 5.5.1.
5.9.3 Conditioning
The capacitance shall be tested in accordance with IEC 60068-2-14:2023, Clause 7, test Na for
5 cycles.
The exposure time at each temperature limit shall be 30 min to 3 h as specified in the detail
specification.
The recovery period shall be 16 h.
5.9.4 Final inspection, measurements and requirements
After recovery, the capacitors shall be visually examined, electrically measured and shall meet
the requirements shown in Table 2.

5.10 Vibration
5.10.1 General
IEC 62391-1:2022, 7.3, applies with the following details.
5.10.2 Initial measurement
The capacitance shall be measured in accordance with 5.5.1.
5.10.3 Test conditions
Test Fc in accordance with IEC 60068-2-6:2007, Annex A, shall be conducted with the following
severities.
Frequency range: 10 Hz to 55 Hz
Amplitude: 0,75 mm or acceleration: 100 m/s (whichever is less stringent)
Total test time: 6 h
5.10.4 Final inspection, measurements and requirements
The capacitors shall be visually examined and shall meet the requirements shown in Table 2.
5.11 Maintain voltage
5.11.1 General
IEC 62391-1:2022, 6.4, applies with the following details.
5.11.2 Test conditions
The discharge time before testing shall be at least 12 h, unless otherwise agreed between the
manufacturer and the customer.
The charge voltage shall be the rated voltage. Any requirements for another charge voltage
shall be specified in the detail specification.
Charging time: 8 h.
5.11.3 Final inspection, measurements and requirements
The measurement time shall be 24 h, unless otherwise agreed between the manufacturer and
the customer.
The capacitors shall be measured retention voltage and shall meet the requirements shown in
Table 2.
5.12 Storage at high temperature
5.12.1 General
IEC 62391-1:2022, 5.4.1, applies with the following details.
5.12.2 Initial measurement
The capacitance shall be measured in accordance with 5.5.1. The internal resistance shall be
measured in accordance with 5.5.2.

– 14 – IEC 62391-2:2025 © IEC 2025
5.12.3 Test conditions
Temperature: upper category temperature;
Duration: 96 h ± 4 h
5.12.4 Final inspection, measurements and requirements
After recovery for a minimum of 16 h, the capacitors shall be visually examined and measured.
They shall meet the requirements given in Table 2.
5.13 Damp heat, steady state
5.13.1 General
IEC 62391-1:2022, 8.2, applies with the following details.
5.13.2 Initial measurement
The capacitance shall be measured in accordance with 5.5.1. The internal resistance shall be
measured in accordance with 5.5.2.
5.13.3 Conditioning of test
No voltage shall be applied.
5.13.4 Final inspection, measurements and requirements
After recovery for 1 h to 2 h, the capacitors shall be visually examined and electrically measured.
They shall meet the requirements shown in Table 2.
5.14 Endurance
5.14.1 General
IEC 62391-1:2022, 8.3, applies with the following details.
5.14.2 Initial measurement
The capacitance shall be measured in accordance with 5.5.1. The internal resistance shall be
measured in accordance with 5.5.2.
5.14.3 Test conditions
Unless otherwise agreed between the manufacturer and the customer, the test conditions shall
be as follows.
Duration: 1 000 h for capacitors belonging to the 70 °C upper category temperature;
2 000 h for capacitors belonging to the 60 °C upper category temperature.
Applied voltage: category voltage, unless otherwise specified in the detail specification.
NOTE When the category voltage is different from the rated voltage, the tested sample is divided into two parts
which are subjected to the rated temperature at the category voltage respectively.
5.14.4 Final inspection, measurements and requirements
After recovery for a minimum of 16 h, the capacitors shall be visually examined and measured
and shall meet the requirements shown in Table 2.

5.15 Characteristics at high and low temperature
5.15.1 General
IEC 62391-1:2022, 8.4, applies with the following details.
5.15.2 Measurements and requirements
The capacitor shall be measured and shall meet the requirements shown in Table 2.
5.16 Passive flammability (if applicable)
5.16.1 General
IEC 62391-1:2022, 10.1, applies with the following details.
No preconditioning is required.
The flame shall be applied for the period of time specified in IEC 62391-1 corresponding to the
volume of the specimen and the flammability category specified in the detail specification.
The flammability category shall be C, unless otherwise specified in the detail specification.
5.16.2 Requirements
The burning time specified in IEC 62391-1 shall not be exceeded.
5.17 Pressure relief (if applicable)
5.17.1 General
IEC 62391-1:2022, 10.2, applies.
5.17.2 Requirements
The pressure relief device shall open in such a way as to avoid any danger of explosion or fire.
6 Marking
6.1 General
IEC 62391-1:2022, 4.3, applies with the following details.
6.2 Information for marking
The information given in the marking on the capacitor and on the packaging is normally selected
from the following list; the relative importance of each item is indicated by its position in the list:
a) polarity of the terminations (unless identified by construction);
b) nominal capacitance;
c) rated voltage (DC voltage may be indicated by symbol      [IEC 60417-5031(2002-10)]
or     );
d) type of capacitor (in accordance with Clause 1) (if applicable);
e) year and month (or week) of manufacture;
f) either the manufacturer's name or trademark or both;
g) manufacturer's type designation;
h) classification for lead terminal processing (if applicable).

– 16 – IEC 62391-2:2025 © IEC 2025
6.3 Marking on the capacitors
Information listed as a), b) and c) in 6.2 shall be marked on the capacitors. The rest of the
information items listed in 6.2 should be marked on the capacitors as far as possible. Marked
information shall not overlap. The marking on the capacitors shall be legible and not easily
smeared or removed by rubbing with the finger.
6.4 Marking of the packaging
The packaging containing the capacitor(s) shall be clearly marked with all the information listed
in 6.2, except polarity (list item 6.2 a)), unless this is applicable to the method of packaging.
6.5 Additional marking
Any additional marking not specified in 6.2, shall be so applied that no confusion can arise.
7 Information to be given in a detail specification
7.1 General
The detail specifications shall be derived from the relevant blank detail specification.
Detail specifications shall not specify requirements inferior to those of the generic, sectional or
blank detail specification. When more severe requirements are included, they shall be indicated
in the test schedules, for example by an asterisk.
The information given in 7.2 may be presented in tabular form if more convenient.
The information in 7.2 to 7.5 shall be given in each detail specification and the values quoted
should be selected from those given in the appropriate clause of this document.
7.2 Outline drawing and dimensions
There shall be an illustration of the surface mount capacitors as an aid to easy recognition and
for comparison of the surface mount capacitors with others.
Dimensions and their associated tolerances, which affect interchangeability and mounting, shall
be given in the detail specification. All dimensio
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