IEC 60115-4:2022

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

IEC 60115-4:2022(E) 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 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.
This edition includes the following significant technical changes with respect to the previous edition:  
the definitions of product technologies and product classification levels of the generic specification, IEC 60115-1:2020, have been adopted;
a basis for the optional specification of the lead eccentricity of axial leaded resistors has been amended in 4.2;
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;
the revised solderability test of IEC 60115-1:2020, 11.1 has been adopted in 5.3.22 and 5.3.23;
the combined solvent resistance test of IEC 60115-1:2020, 11.3 has been adopted in 5.3.25;
the 'endurance at room temperature test' of IEC 60115-1:2020, 7.2 has been reworked and adopted in 5.3.5;
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.
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;
inclusion of an optional flammability test as 5.4.8;
new guidance is provided in 6.2 on the presentation of stability requirements with their permissible absolute and relative deviations;
acceptance criteria for the visual inspection have been added in 6.5 and in Annex B;
visual inspection for the primary and proximity packaging has been added in 6.5.3 and in 7.2;
the periodical evaluation of termination platings has been added as a new topic of quality assessment in 9.8;
the revised test clause numbering of IEC 60115-1:2020 has been applied;
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;
the informative Annex F on radial formed styles has been amended with details on a formed Z-bend style for surface-mount assembly;
furthermore, the informative Annex X has been ad

General Information

• Status: Published
• Publication Date: 28-Nov-2022
• ICS: 31.040.10 - Fixed resistors
• Technical Committee: TC 40 - Capacitors and resistors for electronic equipment
• Drafting Committee: MT 60115-4 - TC 40/MT 60115-4
• Current Stage: PPUB - Publication issued
• Start Date: 27-Dec-2022
• Completion Date: 29-Nov-2022

Standards Content (Sample)

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
IEC 60115-4:2022-11(en)

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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




  Warning! Make sure that you obtained this publication from an authorized distributor.


® Registered trademark of the International Electrotechnical Commission

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– 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

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IEC 60115-4:2022 © IEC 2022 – 3 –
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

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– 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
70
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

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IEC 60115-4:2022 © IEC 2022 – 5 –
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

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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 .
...