IEC 60115-4:2022

IEC 60115-4 ®
Edition 3.0 2022-11
INTERNATIONAL
STANDARD
colour
inside
Fixed resistors for use in electronic equipment –
Part 4: Sectional specification: Power resistors for through hole assembly on
circuit boards (THT) or for assembly on chassis
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IEC 60115-4 ®
Edition 3.0 2022-11
INTERNATIONAL
STANDARD
colour
inside
Fixed resistors for use in electronic equipment –

Part 4: Sectional specification: Power resistors for through hole assembly on

circuit boards (THT) or for assembly on chassis

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 31.040.10 ISBN 978-2-8322-6088-3

– 2 – IEC 60115-4:2022 © IEC 2022
CONTENTS
FOREWORD . 8
1 Scope . 11
2 Normative references . 11
3 Terms, definitions, product types, product technologies and product classification. 12
3.1 Terms and definitions . 12
3.2 Product types . 13
3.2.1 General . 13
3.2.2 Axial type . 13
3.2.3 Radial type . 13
3.2.4 Vertical type . 14
3.2.5 Tubular types . 14
3.2.6 Metal housed wire-wound resistors . 15
3.2.7 Any other type . 15
3.3 Resistor encapsulation and material of termination . 15
3.3.1 Conformal lacquer coat . 15
3.3.2 Silicone cement coating . 15
3.3.3 Enamel coating . 16
3.3.4 Ceramic housed resistor . 16
3.3.5 Wire termination . 16
3.4 Product technologies . 16
3.4.1 General . 16
3.4.2 Metal film technology . 17
3.4.3 Metal glaze technology . 17
3.4.4 Metal oxide technology . 17
3.4.5 Wire-wound technology . 17
3.4.6 Metal strip technology . 17
3.4.7 Any other technology . 18
3.5 Product classification . 18
4 Preferred characteristics . 18
4.1 General . 18
4.2 Preferred types, styles and dimensions . 18
4.2.1 Axial type . 18
4.2.2 Ceramic housed type with axial lead wires . 22
4.2.3 Ceramic housed type with radial lead wires . 23
4.2.4 Radial or vertical ceramic housed type and dimensions . 25
4.2.5 Tubular type of power resistors . 26
4.2.6 Other types . 27
4.3 Preferred climatic categories . 27
4.4 Resistance . 28
4.5 Tolerances on resistance . 28
4.6 Rated dissipation P . 28
r
4.7 Limiting element voltage U . 30
max
4.8 Insulation voltage U . 30
ins
4.9 Insulation resistance R . 30
ins
5 Tests and test severities . 30
5.1 General provisions for tests invoked by this specification . 30

5.2 Preparation of specimen . 31
5.2.1 Drying . 31
5.2.2 Mounting of power resistors on test boards . 31
5.2.3 Mounting of power resistors on test racks . 32
5.2.4 Specification of test boards/ racks for any other type of high-power

resistors . 34
5.3 Details of applicable tests . 34
5.3.1 Resistance . 34
5.3.2 Temperature coefficient of resistance . 34
5.3.3 Temperature rise . 35
5.3.4 Endurance at the rated temperature 70 °C . 35
5.3.5 Endurance at room temperature . 36
5.3.6 Endurance at a maximum temperature: UCT with category dissipation . 37
5.3.7 Short-term overload . 37
5.3.8 Single-pulse high-voltage overload test . 38
5.3.9 Periodic-pulse high-voltage overload test . 38
5.3.10 Visual examination . 40
5.3.11 Gauging of dimensions . 40
5.3.12 Detail dimensions . 41
5.3.13 Robustness of the resistor body . 41
5.3.14 Robustness of terminations . 41
5.3.15 Bump . 42
5.3.16 Shock . 42
5.3.17 Vibration . 42
5.3.18 Rapid change of temperature . 43
5.3.19 Rapid change of temperature, ≥ 100 cycles . 43
5.3.20 Climatic sequence . 43
5.3.21 Damp heat, steady state . 44
5.3.22 Solderability, with lead-free solder . 45
5.3.23 Solderability, with SnPb solder . 46
5.3.24 Resistance to soldering heat . 46
5.3.25 Solvent resistance . 47
5.3.26 Insulation resistance . 47
5.3.27 Voltage proof . 47
5.4 Optional and/or additional tests . 48
5.4.1 Single-pulse high-voltage overload test . 48
5.4.2 Periodic-pulse overload test . 48
5.4.3 Electrostatic discharge (ESD) . 49
5.4.4 Robustness of threaded stud or screw terminations . 49
5.4.5 Operation at low temperature. 50
5.4.6 Damp heat, steady state, accelerated . 50
5.4.7 Accidental overload test. 51
5.4.8 Flammability . 51
6 Performance requirements. 52
6.1 General . 52
6.2 Limits for change of resistance at test . 52
6.3 Temperature coefficient of resistance . 54
6.4 Temperature rise . 54
6.5 Visual inspection . 55

– 4 – IEC 60115-4:2022 © IEC 2022
6.5.1 General visual criteria . 55
6.5.2 Visual criteria after tests . 55
6.5.3 Visual criteria for the packaging . 55
6.6 Solderability . 55
6.7 Insulation resistance . 56
6.8 Flammability . 56
6.9 Accidental overload test . 56
7 Marking, packaging and ordering information . 56
7.1 Marking of the component . 56
7.2 Packaging . 56
7.3 Marking of the packaging . 57
7.4 Ordering information . 57
8 Detail specifications . 57
8.1 General . 57
8.2 Information to be specified in a detail specification . 58
8.2.1 Outline drawing or illustration . 58
8.2.2 Type, style, and dimensions . 58
8.2.3 Climatic category . 58
8.2.4 Resistance range . 58
8.2.5 Tolerances on rated resistance . 58
8.2.6 Rated dissipation P . 58
8.2.7 Limiting element voltage U . 59
max
8.2.8 Insulation voltage U . 59
ins
8.2.9 Insulation resistance R . 59
ins
8.2.10 Tests and test severities . 59
8.2.11 Limits of resistance change after testing . 59
8.2.12 Temperature coefficient of resistance . 59
8.2.13 Marking . 59
8.2.14 Ordering information . 59
8.2.15 Mounting . 59
8.2.16 Storage. 60
8.2.17 Transportation . 60
8.2.18 Additional information . 60
8.2.19 Quality assessment procedures . 60
9 Quality assessment procedures . 60
9.1 General . 60
9.2 Definitions. 60
9.2.1 Primary stage of manufacture . 60
9.2.2 Structurally similar components . 60
9.2.3 Assessment level EZ . 61
9.3 Formation of inspection lots . 61
9.4 Approved component (IECQ AC) procedures . 62
9.5 Qualification approval (QA) procedures . 62
9.5.1 General . 62
9.5.2 Qualification approval . 62
9.5.3 Quality conformance inspection . 62
9.6 Capability certification (IECQ AC-C) procedures . 63
9.7 Technology certification (IECQ-AC-TC) procedures . 63

9.8 Periodical evaluation of termination platings . 63
9.9 Delayed delivery . 63
9.10 Certified test records. 63
9.11 Certificate of conformity (CoC) . 63
Annex A (normative) Symbols and abbreviated terms . 74
A.1 Symbols . 74
A.2 Abbreviated terms . 77
Annex B (normative) Visual inspection acceptance criteria. 79
B.1 General . 79
B.2 Acceptance criteria for a general visual inspection of body of specimens . 79
B.3 Acceptance criteria for a general visual inspection of the terminals . 79
B.4 Acceptance criteria for a general visual inspection of specimen after test . 79
Annex C (normative) Workmanship requirements for the assembly of power resistors. 80
C.1 General . 80
C.2 Lead forming . 80
C.2.1 General . 80
C.2.2 Means for support of mounting height . 81
C.3 Mounting . 82
C.3.1 General . 82
C.3.2 Lateral mounting . 83
C.3.3 Upright mounting . 84
C.4 Lead trimming . 85
Annex D (informative) Zero ohm resistors (jumpers) . 87
Annex E (informative) Guide on the application of optional and/or additional tests . 88
E.1 General . 88
E.2 Endurance at room temperature . 88
E.3 Single-pulse high-voltage overload test . 89
E.4 Periodic-pulse overload test . 90
E.5 Operation at low temperature . 91
E.6 Damp heat, steady state, accelerated . 92
E.7 Accidental overload test . 93
E.8 Flammability test . 94
E.9 Electrostatic discharge test (ESD) . 95
E.10 Robustness of threaded stud or screw terminations . 96
Annex F (informative) Radial formed types from axial styles . 98
F.1 General . 98
F.1.1 Applicability of this annex . 98
F.1.2 Denomination of radial formed styles . 98
F.1.3 Coated lead wires . 100
F.1.4 Means for support of mounting height . 100
F.1.5 Means for retention . 101
F.2 Radial formed types for through hole assembly . 101
F.2.1 Radial formed style with lateral body position . 101
F.2.2 Radial formed style with upright body position . 103
F.3 Radial formed types for surface-mount assembly . 105
F.4 Packaging . 106
F.4.1 Packaging of resistors formed for through-hole assembly . 106
F.4.2 Packaging of resistors formed for surface-mount assembly . 107

– 6 – IEC 60115-4:2022 © IEC 2022
F.5 Quality assessment . 107
F.5.1 General . 107
F.5.2 Quality assessment of formed resistors . 107
F.5.3 Forming of finished resistors of assessed quality . 108
F.5.4 Special inspection requirements . 108
Annex X (informative) Cross references for the prior revision of this specification . 109
Bibliography . 112

Figure 1 – Illustrations of typical axial leaded power resistors . 13
Figure 2 – Illustrations of typical radial leaded power resistors . 13
Figure 3 – Illustrations of typical vertical leaded power resistors with punched
terminals . 14
Figure 4 – Illustrations of typical tubular type power resistors . 14
Figure 5 – Illustrations of typical metal housed power resistors . 15
Figure 6 – Shape and dimensions of cylindrical axial leaded resistors . 19
Figure 7 – Alternative methods for specification of the length of excessive protective
coating or welding beads on axial leaded resistors . 20
Figure 8 – Lead-wire spacing of axial leaded resistors with bent leads . 21
Figure 9 – Specification of the lead eccentricity of axial leaded resistors . 22
Figure 10 – Shape and dimensions of axial leaded ceramic housed resistors . 22
Figure 11 – Shape and dimensions of radial type ceramic resistors . 24
Figure 12 – Shape and dimensions of radial leaded ceramic resistors . 25
Figure 13 – Shape and dimensions of tubular resistors . 26
Figure 14 – Typical derating curve for MET > UCT . 29
Figure 15 – Typical derating curve for power wire-wound resistors . 29
Figure 16 – Assembly of specimen to the test board . 32
Figure 17 – Mounting of axial leaded specimens on a rack, top view . 33
Figure 18 – Examples of specimen lead fixation devices . 34
Figure C.1 – Lead forming dimensions . 80
Figure C.2 – Examples of mounting height support . 82
Figure C.3 – Clearance between coating and solder . 83
Figure C.4 – Lateral mounting . 83
Figure C.5 – Upright mounting . 84
Figure C.6 – Lead protrusion . 85
Figure C.7 – Lead end distortion . 86
Figure F.1 – Production flow and different scopes of quality assurance . 99
Figure F.2 – Shape and dimensions of radial formed resistor for lateral body position . 101
Figure F.3 – Shape and dimensions of radial formed resistor for lateral body position
with kinked lead wires . 101
Figure F.4 – Shape and dimensions of radial formed resistor for upright body position. 103
Figure F.5 – Shape and dimensions of radial formed resistor for upright body position
and wide spacing . 103
Figure F.6 – Shape and dimensions of radial formed resistor for upright body position
and wide spacing, with kinked lead wire . 104
Figure F.7 – Shape and dimensions of radial formed resistor for surface-mount

assembly (Z-bend) . 105

Figure F.8 – Land pattern dimensions for surface-mount assembly . 106

Table 1 – Examples of preferred styles of cylindrical axial leaded power resistors . 19
Table 2 – Examples of preferred styles of axial leaded ceramic housed resistors . 23
Table 3 – Examples of preferred styles of radial type ceramic resistors. 24
Table 4 – Preferred styles of radial or vertical mount ceramic resistors . 26
Table 5 – Example of preferred styles of tubular types of power resistors . 27
Table 6 – Preferred alternative overload conditions . 40
Table 7 – Limits for resistance variations at tests . 53
Table 8 – Permitted change of resistance due to the temperature coefficient of
resistance . 54
Table 9 – Test schedule for the qualification approval of power resistors . 64
Table 10 – Test schedule for quality conformance inspection of power resistors . 69
Table C.1 – Lead bend radius . 81
Table C.2 – Recommended circuit board bore diameters . 82
Table C.3 – Clearance of lateral mounted resistors . 84
Table E.1 – Implementation of the test endurance at room temperature . 89
Table E.2 – Implementation of the single-pulse high-voltage overload test . 90
Table E.3 – Implementation of the periodic-pulse overload test . 91
Table E.4 – Implementation of the operation at low temperature test . 92
Table E.5 – Implementation of the test damp heat, steady state, accelerated . 93
Table E.6 – Implementation of the test accidental overload test . 94
Table E.7 – Implementation of the test flammability . 95
Table E.8 – Implementation of the test Electrostatic discharge (ESD) . 96
Table E.9 – Implementation of the test Robustness of threaded stud or screw

terminations . 97
Table F.1 – Feasible lead-wire spacing of radial formed resistor for
lateral body position . 102
Table F.2 – Feasible lead-wire spacing of radial formed resistor for
upright body position . 105
Table X.1 – Cross reference for references to clauses . 110
Table X.2 – Cross reference for references to figures . 111
Table X.3 – Cross reference for references to tables . 111

– 8 – IEC 60115-4:2022 © IEC 2022
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
FIXED RESISTORS FOR USE IN ELECTRONIC EQUIPMENT –

Part 4: Sectional specification: Power resistors for through hole
assembly on circuit boards (THT) or for assembly on chassis

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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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
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expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
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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.
IEC 60115-4 has been prepared by IEC technical committee 40: Capacitors and resistors for
electronic equipment. It is an International Standard.
This third edition cancels and replaces the second edition published in 1982 and
Amendment 1:1993. This edition constitutes a technical revision and includes test conditions
and requirements for lead-free soldering and assessment procedures meeting the requirements
of a "zero defect" approach.
This edition includes the following significant technical changes with respect to the previous
edition:
a) the definitions of product technologies and product classification levels of the generic
specification, IEC 60115-1:2020, have been adopted;
b) a basis for the optional specification of the lead eccentricity of axial leaded resistors has
been amended in 4.2;
c) the 'period-pulse high-voltage overload test' of IEC 60115-1:2020, 8.3 has been adopted as
default test method in 5.3.9, thereby replacing the legacy test 'periodic-pulse overload test
of IEC 60115-1:2020, 8.4;
d) the revised solderability test of IEC 60115-1:2020, 11.1 has been adopted in 5.3.22 and
5.3.23;
e) the combined solvent resistance test of IEC 60115-1:2020, 11.3 has been adopted in 5.3.25;
f) the 'endurance at room temperature test' of IEC 60115-1:2020, 7.2 has been reworked and
adopted in 5.3.5;
g) the 'single-pulse high-voltage overload test' of IEC 60115-1:2020, 8.2, applied with the pulse
shape 10/700 in 5.3.8, is complemented with the optional alternative provided by the pulse
shape 1,2/50 in 5.4.1.
h) climatic tests for 'operation at low temperature' of IEC 60115 1:2020, 10.2, and for 'damp
heat, steady state, accelerated' of IEC 60115‑1:2020, 10.5, have been adopted as optional
tests in 5.4.5. and 5.4.6, respectively;
i) inclusion of an optional flammability test as 5.4.8;
j) new guidance is provided in 6.2 on the presentation of stability requirements with their
permissible absolute and relative deviations;
k) acceptance criteria for the visual inspection have been added in 6.5 and in Annex B;
l) visual inspection for the primary and proximity packaging has been added in 6.5.3 and in
7.2;
m) the periodical evaluation of termination platings has been added as a new topic of quality
assessment in 9.8;
n) the revised test clause numbering of IEC 60115-1:2020 has been applied;
o) a new Annex C has been added to summarize workmanship requirements for the assembly
of leaded power resistors, e.g. as given in the prior IEC 61192 series of standards;
p) the informative Annex F on radial formed styles has been amended with details on a formed
Z-bend style for surface-mount assembly;
q) furthermore, the informative Annex X has been added to show the cross-references to the
prior edition of this document.
The text of this International Standard is based on the following documents:
Draft Report on voting
40/2920/CDV 40/2963/RVC
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.
A list of all parts in the IEC 60115 series, published under the general title Fixed resistors for
use in electronic equipment, can be found on the IEC website.
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.

– 10 – IEC 60115-4:2022 © IEC 2022
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,
• replaced by a revised edition, or
• amended.
IMPORTANT – The "colour inside" logo on the cover page of this document indicates that it
contains colours which are considered to be useful for the correct understanding of its
contents. Users should therefore print this document using a colour printer.

FIXED RESISTORS FOR USE IN ELECTRONIC EQUIPMENT –

Part 4: Sectional specification: Power resistors for through hole
assembly on circuit boards (THT) or for assembly on chassis

1 Scope
This part of IEC 60115 relates to resistors having a rated dissipation typically greater than 1 W
up to and including 1 000 W for use in electronic equipment. This document is applicable to
fixed power resistors with a maximum surface temperature (MET) higher than the preferred
upper category temperature (UCT) of 200 °C.
NOTE Heat sink resistors, i.e. resistors which in their operation depend on being mounted on a dedicated heat sink,
owing to their special temperature conditions, are covered by a special sectional specification (under consideration
at the time of publication).
These resistors are typically described according to types (different geometric shapes) and
styles (different dimensions), and product technology.
The resistive element of these resistors is typically
– protected by a conformal lacquer coating, or
– cement coating, or
– vitreous enamel, or
– a ceramic body, or
– any other housing, which is to be described in the relevant specification.
The electrical connection of these resistors is typically achieved by means of
– axial leads for through hole assembly (THT), or
– vertical or radial leads or punched terminals, or
– ferrules or lugs for chassis mount, or
– push on terminals, or
– screw terminals, or
– any other termination, which is to be described in the relevant specification.
In special cases, a heat sink can be applicable but not mandatory.
The object of this document is to define preferred ratings and characteristics and to select from
IEC 60115-1 the appropriate quality assessment procedures, tests and measuring methods and
to give general performance requirements for this type of resistor.
NOTE SMD resistors are covered by IEC 60115-8, regardless of their dissipation.
2 Normative references
The following doc
...