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
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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– 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 .
...