IEC 60401-1:2020 is available as IEC 60401-1:2020 RLV which contains the International Standard and its Redline version, showing all changes of the technical content compared to the previous edition.

IEC 60401-1:2020 provides a nomenclature of the most frequent surface, bulk and shape irregularities relevant to cores made of soft ferrites (magnetic oxides). Most irregularities are graphically exemplified as visual aids. A general recommendation is also given in Annex A for a consistent scheme for specifying the exact location of the irregularity, combining a general name for the location with more detailed qualifiers of the specified location. This document can also be useful as a terminology reference when preparing technical documentation, irregularity inspection specifications, etc. This document also presents a method for defining the designation nomenclature for the major physical attributes of soft ferrite core shapes. The purpose of this document is to facilitate uniform usage of dimensional characters by manufacturers, specifiers, and users when describing core dimensions on drawings, in tables, and on catalogue specification sheets. This second edition cancels and replaces the first edition of IEC 60401-1 published in 2002 and the second edition of IEC 60401-2 published in 2009. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous editions of IEC 60401-1 and IEC 60401-2:
- added the surface irregularity term “pores” in 4.3.1.6;
- added the surface irregularity term “scratch” in 4.3.6.3;
- removed the surface irregularity term “crater” in 4.1.5 of IEC 60401-1: 2002;
- removed the bulk irregularity terms “superpores” in 5.1, “inclusions” in 5.2, “internal stratification” in 5.3 and “internal crack” in 5.4 of IEC 60401-1: 2002;
- removed the contents related to “yoke ring cores” in 7.1.3 and 7.4 of IEC 60401-1:2002;
- replaced the surface irregularity term “stratification” with “lamination” in 4.3.4.7;
- replaced the location related terms “upper surface of back” with “bottom surface” and “lower surface of back” with “back surface” in Figure A.1;
- changed Clause 7 of IEC 60401-1:2002 into Annex A.