IEC 60115-4 Ed. 3.0 en: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:

1. the definitions of product technologies and product classification levels of the generic specification, IEC 60115-1:2020, have been adopted;
2. a basis for the optional specification of the lead eccentricity of axial leaded resistors has been amended in 4.2;
3. 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;
4. the revised solderability test of IEC 60115-1:2020, 11.1 has been adopted in 5.3.22 and 5.3.23;
5. the combined solvent resistance test of IEC 60115-1:2020, 11.3 has been adopted in 5.3.25;
6. the 'endurance at room temperature test' of IEC 60115-1:2020, 7.2 has been reworked and adopted in 5.3.5;
7. 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.
8. 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;
9. inclusion of an optional flammability test as 5.4.8;
10. new guidance is provided in 6.2 on the presentation of stability requirements with their permissible absolute and relative deviations;
11. acceptance criteria for the visual inspection have been added in 6.5 and in Annex B;
12. visual inspection for the primary and proximity packaging has been added in 6.5.3 and in 7.2;
13. the periodical evaluation of termination platings has been added as a new topic of quality assessment in 9.8;
14. the revised test clause numbering of IEC 60115-1:2020 has been applied;
15. 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;
16. the informative Annex F on radial formed styles has been amended with details on a formed Z-bend style for surface-mount assembly;
17. furthermore, the informative Annex X has been ad