IEC 63093-2:2025

Ferrite cores - Guidelines on dimensions and the limits of surface irregularities - Part 2: Pot-cores for use in telecommunications, power supply, and filter applications

IEC 63093-2:2025 specifies the dimensions that are of importance for mechanical interchangeability for a preferred range of pot-cores made of ferrite, and the dimensional limits for coil formers to be used with them, as well as the effective parameter values to be used in calculations involving them. It also gives guidelines on the allowable limits of surface irregularities applicable to pot-cores in accordance with the relevant generic specification. The selection of core sizes and shapes for this document is based on the philosophy of including those sizes which are industrial standards, either by inclusion in a national standard, or by broad-based use in industry. The general considerations upon which the design of this range of cores is based are given in Annex A.
This edition includes the following significant technical changes with respect to the previous edition:
a) revision of Table 4 and Table 5 according to IEC 60205:2016.

Noyaux ferrite - Lignes directrices relatives aux dimensions et limites des irrégularités de surface - Partie 2: Circuits magnétiques en pots utilisés dans des applications de télécommunications, d'alimentation électrique et de filtre

General Information

• Status: Published
• Publication Date: 14-Dec-2025
• ICS: 29.100.10 - Magnetic components
• Technical Committee: TC 51 - Magnetic components, ferrite and magnetic powder materials
• Drafting Committee: WG 1 - TC 51/WG 1
• Current Stage: PPUB - Publication issued
• Start Date: 15-Dec-2025
• Completion Date: 02-Jan-2026

Relations

• Revises: IEC 63093-2:2020 - Ferrite cores - Guidelines on dimensions and the limits of surface irregularities - Part 2: Pot-cores for use in telecommunications, power supply, and filter applications
• Effective Date: 22-Dec-2023

Overview

IEC 63093-2:2025 - Ferrite cores: Guidelines on dimensions and the limits of surface irregularities - Part 2 covers pot-cores used in telecommunications, power supplies and filter applications. The standard defines the dimensional requirements needed for mechanical interchangeability, the limits for surface irregularities, and the effective parameter values to be used in electromagnetic calculations. This edition updates effective-parameter tables in line with IEC 60205:2016.

Key topics and technical requirements

• Principal dimensions and interchangeability

  • Defines the primary dimensions for a preferred range of pot-core sizes (see Tables and Figures) to ensure mechanical interchangeability of complete assemblies and wound coil formers.
  • Includes recommended gauge checks and guidance on acceptable corner radii and tolerances.

• Wire-ways and back-wall slots

  • Specifies limits for slot and wire-way dimensions (e.g., width and depth ranges) so wire leads can pass from the coil centre to the outside without compromising fit or function.

• Coil former dimensions

  • Lists main dimensions and limits for coil formers compatible with the pot-core range to guarantee correct mating and manufacturability.

• Effective parameter values

  • Provides effective inductance/parameter values and calculation inputs (updated per IEC 60205) used for design and simulation of magnetic components.

• Limits of surface irregularities

  • Gives visual inspection criteria and quantitative limits for chips, cracks, pull-outs, pores, flash and ragged edges. Includes illustrative figures and tables for area/length references and acceptable defect levels.

• Supporting annexes

  • Annex A: Informative design considerations for pot-cores.
  • Annex B: Example gauges and procedures for dimensional verification.

Practical applications and users

Who uses IEC 63093-2:2025:

• Ferrite core manufacturers (production tolerancing and QA)
• Magnetic-component designers (inductors, chokes, filters, small power transformers)
• PCB and power-supply designers specifying mechanical fit and magnetic performance
• Quality inspectors, test labs and procurement teams establishing acceptance criteria
• Manufacturing engineers integrating coil formers and assembly interchangeability

How it’s applied:

• Specify pot-core dimensions and surface-quality acceptance in supplier contracts
• Use effective parameter values for circuit simulations and EMI/filter design
• Implement visual and gauge-based QC procedures on incoming cores and assemblies
• Select standardized pot-core sizes to simplify sourcing and interchangeability across product lines

Related standards

• IEC 63093-1 - Ferrite cores: general specification and terminology
• IEC 60205 - Calculation of the effective parameters of magnetic piece parts (relevant to Tables 4 and 5)
• IEC 60401-1 - Terms and nomenclature for ferrite cores (physical irregularities and dimension references)

Keywords: IEC 63093-2:2025, ferrite cores, pot-cores, dimensions, surface irregularities, coil formers, effective parameter values, mechanical interchangeability, wire-ways, telecommunications, power supply, filter applications.

Standards Content (Sample)

IEC 63093-2 ®
Edition 2.0 2025-12
INTERNATIONAL
STANDARD
Ferrite cores - Guidelines on dimensions and the limits of surface irregularities -
Part 2: Pot-cores for use in telecommunications, power supply, and filter
applications
ICS 29.100.10  ISBN 978-2-8327-0908-5

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CONTENTS
FOREWORD . 3
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 5
4 Primary dimensions . 5
4.1 Dimensions of pot-cores . 5
4.1.1 General . 5
4.1.2 Principal dimensions . 6
4.1.3 Wire-ways . 8
4.1.4 Effective parameter values . 8
4.2 Main dimensions for coil formers . 9
5 Limits of surface irregularities . 10
5.1 General . 10
5.2 Examples of surface irregularities . 10
5.3 Chips and ragged edges . 11
5.3.1 General . 11
5.3.2 Chips and ragged edges on the mating surfaces . 11
5.3.3 Chips and ragged edges on the other surfaces . 11
5.4 Cracks . 13
5.5 Pull-out, crystallite and pore locations . 14
5.6 Flash . 15
Annex A (informative) Pot-core design . 16
Annex B (informative) Example of gauges to check the dimensions of pot-cores . 17
B.1 General . 17
B.2 Procedure and requirements . 18

Figure 1 – Principal dimensions of pot-cores without back wall slots . 6
Figure 2 – Principal dimensions of pot-cores with back wall slots . 7
Figure 3 – Main dimensions of coil formers for pot-cores . 9
Figure 4 – Examples of surface irregularities . 10
Figure 5 – Chips and ragged edge location for pot-cores . 11
Figure 6 – Cracks location – Top view . 13
Figure 7 – Cracks location – Bottom view . 13
Figure 8 – Pull-out, crystallite and pore locations . 14
Figure 9 – Flash location . 15
Figure B.1 – Dimensions of gauge A . 17
Figure B.2 – Dimensions of gauges B and C . 18

Table 1 – Principal dimensions of pot-cores . 6
Table 2 – Limits for dimensions C and G . 7
Table 3 – Minimum wire-way depth . 8
Table 4 – Effective parameter values for pot-cores with a centre hole . 8
Table 5 – Effective parameter values for pot-cores without a centre hole . 9
Table 6 – Main dimensions of coil formers for pot-cores. 10
Table 7 – Area and length references of irregularities for visual inspection . 12
Table 8 – Limits for cracks . 14
Table A.1 – Ratio of diameter to height . 16
Table B.1 – Dimensions of gauge A . 17
Table B.2 – Dimensions of gauges B and C . 18

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
Ferrite cores - Guidelines on dimensions
and the limits of surface irregularities -
Part 2: Pot-cores for use in telecommunications,
power supply, and filter applications

FOREWORD
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IEC 63093-2 has been prepared by IEC technical committee 51: Magnetic components, ferrite
and magnetic powder materials. It is an International Standard.
This second edition cancels and replaces the first edition published in 2020. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) revision of Table 4 and Table 5 according to IEC 60205:2016.
The text of this International Standard is based on the following documents:
Draft Report on voting
51/1581/FDIS 51/1588/RVD
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.
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.
A list of all parts in the IEC 63093 series, published under the general title Ferrite cores -
Guidelines on dimensions and the limits of surface irregularities, can be found on the IEC
website.
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, or
– revised.
1 Scope
This part of IEC 63093 specifies the dimensions that are of importance for mechanical
interchangeability for a preferred range of pot-cores made of ferrite, and the dimensional limits
for coil formers to be used with them, as well as the effective parameter values to be used in
calculations involving them. It also gives guidelines on the allowable limits of surface
irregularities applicable to pot-cores in accordance with the relevant generic specification.
The selection of core sizes and shapes for this document is based on the philosophy of including
those sizes which are industrial standards, either by inclusion in a national standard, or by
broad-based use in industry.
The general considerations upon which the design of this range of cores is based are given in
Annex A.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies.
For undated references, the latest edition of the referenced document (including any
amendments) applies.
IEC 60205, Calculation of the effective parameters of magnetic piece parts
IEC 60401-1, Terms and nomenclature for cores made of magnetically soft ferrites - Part 1:
Terms used for physical irregularities and reference of dimensions
IEC 63093-1, Ferrite cores - Guidelines
...