kSIST FprEN IEC 60297-3-103:2026

• Status: Not Published
• Public Enquiry End Date: 31-Jan-2026
• ICS: 31.240 - Mechanical structures for electronic equipment
• Technical Committee: I11 - Imaginarni 11
• Current Stage: 5020 - Formal vote (FV) (Adopted Project)
• Start Date: 17-Aug-2026
• Due Date: 05-Oct-2026
• Ref Project: FprEN IEC 60297-3-103:2026 - Mechanical structures for electrical and electronic equipment - Dimensions of mechanical structures of the 482,6 mm (19 in) series - Part 3-103: Keying and alignment pin

• Revises: SIST EN 60297-3-103:2005 - Mechanical structures for electronic equipment - Dimensions of mechanical structures of the 482,6 mm (19 in) series -- Part 3-103: Keying and alignment pin
• Effective Date: 22-Jul-2025

Overview

kSIST FprEN IEC 60297-3-103:2026 specifies the additional interface dimensions and design requirements for keying and alignment pins used in mechanical structures for electronic equipment featuring the 482,6 mm (19 in) series. Developed by SIST, this standard plays a crucial role in ensuring compatibility, reliability, and modular assembly of subracks and plug-in units in the conventional 19-inch electronic equipment enclosure ecosystem.

This document enhances the series by adding user-oriented guidelines for the design and implementation of keying and alignment features, which prevent incorrect insertion of plug-in units and ensure correct electrical contact and mechanical alignment within subracks.

Key Topics

• Keying Devices
  Specifies the design, dimensions, and positions of keying pins and corresponding retainer features. Keying mechanisms are crucial for preventing misarrangement and ensuring only the correct plug-in units can be inserted into designated subrack positions.

• Alignment Pins
  Introduces dimensions and recommended locations for alignment pins, which ensure precise mechanical alignment and the potential for controlled electrical contact (such as grounding) between plug-in units and subracks.

• Subrack and Plug-in Unit Interfaces
  Details the interface dimensions for both subrack guide rails and plug-in units, supporting modularity and system integrator flexibility.

• Inspection Criteria
  Defines inspection dimensions and reference points for verifying correct alignment and keying placement, supporting quality assurance and manufacturing consistency.

• Programming of Keys
  Outlines the approach for assigning keying pins, including letter and number coding for clear identification and safe functionality, specifically for 3U, 6U, and 9U subracks.

• Guide Rail Offset Accommodation
  Provides guidance on handling the 2,54 mm offset in guide rails and printed board reference planes, ensuring adaptability in design variations.

Applications

Implementing IEC 60297-3-103 offers practical value in various sectors and product types, particularly:

• Telecommunications Infrastructure
  Used to standardize racks and subracks, ensuring modular network equipment (servers, routers, switches, etc.) can be securely installed with proper alignment and anti-misplug functionality.

• Industrial and Automation Systems
  Enables the safe insertion and electrical connection of control modules and signal processing units where high reliability and correct positioning are vital.

• Test and Measurement Equipment
  Provides system builders with dependable mechanical arrangement strategies, minimizing operational errors due to incorrect module placement.

• Modular Computing Platforms
  Facilitates compliance with open bus architectures and interoperability among equipment from different manufacturers, bolstering system scalability.

Keying and alignment pins are widely recognized as an essential safety and maintenance feature, reducing the risk of equipment damage and work interruptions during service operations.

Related Standards

For comprehensive use and integration, this standard is designed to be applied alongside:

• IEC 60297-3-101: Dimensions of mechanical structures of the 482,6 mm (19 in) series - Subracks and associated plug-in units
• IEC 60297-3-102: Dimensions of mechanical structures of the 482,6 mm (19 in) series - Injector/extractor handle
• IEC 60917-1: Modular order for the development of mechanical structures for electrical and electronic equipment practices

Adhering to these standards ensures complete mechanical and electrical interoperability within the 19-inch enclosure systems, promoting industry-wide consistency and system longevity.

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By aligning your equipment designs with kSIST FprEN IEC 60297-3-103:2026, you enhance reliability, serviceability, and modular expansion capabilities-all critical objectives in today’s electronic equipment industry.

SLOVENSKI STANDARD
oSIST prEN IEC 60297-3-103:2026
01-januar-2026
Mehanske konstrukcije elektronske opreme - Mere mehanskih konstrukcij v seriji
482,6 mm (19 in) - 3-103. del: Kodirni in poravnalni trn
Mechanical structures for electronic equipment - Dimensions of mechanical structures of
the 482,6 mm (19 in) series - Part 3-103: Keying and alignment pin
Bauweisen für elektronische Einrichtungen - Maße der 482,6-mm-(19-in-)Bauweise - Teil
3-103: Kodierung und Führungsstift
Structures mécaniques pour équipements électroniques - Dimensions des structures
mécaniques de la série 482,6 mm (19 pouces) - Partie 3-103: Codage et broche
d'alignement
Ta slovenski standard je istoveten z: prEN IEC 60297-3-103:2025
ICS:
31.240 Mehanske konstrukcije za Mechanical structures for
elektronsko opremo electronic equipment
oSIST prEN IEC 60297-3-103:2026 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

oSIST prEN IEC 60297-3-103:2026

oSIST prEN IEC 60297-3-103:2026
48D/795/CDV
COMMITTEE DRAFT FOR VOTE (CDV)
PROJECT NUMBER:
IEC 60297-3-103 ED2
DATE OF CIRCULATION: CLOSING DATE FOR VOTING:
2025-11-14 2026-02-06
SUPERSEDES DOCUMENTS:
48D/791/RR
IEC SC 48D : MECHANICAL STRUCTURES FOR ELECTRICAL AND ELECTRONIC EQUIPMENT
SECRETARIAT: SECRETARY:
Germany Mr Arno Bergmann
OF INTEREST TO THE FOLLOWING COMMITTEES: HORIZONTAL FUNCTION(S):

SC 48B
ASPECTS CONCERNED:
Safety
SUBMITTED FOR CENELEC PARALLEL VOTING NOT SUBMITTED FOR CENELEC PARALLEL VOTING
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TITLE:
Mechanical structures for electronic equipment - Dimensions of mechanical structures of the
482,6 mm (19 in) series - Part 3-103: Keying and alignment pin

PROPOSED STABILITY DATE: 2029
NOTE FROM TC/SC OFFICERS:
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oSIST prEN IEC 60297-3-103:2026
IEC 60297-3-103 ED2 © IEC 2025

Link to Committee Draft for Vote (CDV) online document:
https://osd.iec.ch/#/editor/archive/3877bc98-42bb-df99-e063-b912000a38e2/en/CCDV/1

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oSIST prEN IEC 60297-3-103:2026
IEC 60297-3-103 ED2 © IEC 2025

CONTENTS
CONTENTS . 1
FOREWORD . 3
INTRODUCTION . 5
1 Scope and object . 6
2 Normative references . 6
3 Terms and definitions . 6
4 Arrangement overview: Keying of plug-in units in a subrack. 6
4.1 General . 6
4.2 Subrack interface dimensions for keying . 8
4.3 Plug-in unit keying interface dimensions . 8
4.4 Key dimensions . 8
4.5 Programming of keys . 9
4.6 Keying chamber inspection dimensions . 10
5 Arrangement overview: alignment and/or electrical contact of a plug-in unit to a
subrack . 11
5.1 General . 11
5.2 Alignment and/or electrical contact receptacle in the subrack guide rail for
printed board type plug-in units (width dimension ≥ 4 × 5,08 mm) . 12
5.3 Alignment and/or electrical contact interface inspection dimensions . 13
6 Arrangement overview: Subrack guide rail and printed board, 2,54 mm offset of
the printed board reference plane . 13
6.1 General . 13
6.2 Dimensions of the subrack guide rail with 2,54 mm offset of the printed
board reference plane . 15
6.3 Reference plane for printed boards with 2,54 mm offset position . 16
7 Dimensions used in the figures . 16
Bibliography . 17

Figure 1 – Conventional 19-inch subrack system mechanical structure . 5
Figure 2 – Keying of plug-in unit in a subrack . 7
Figure 3 – Subrack interface dimensions for keying . 8
Figure 4 – Plug-in unit keying interface dimensions . 8
Figure 5 – Key dimensions . 9
Figure 6 – Programming of keys . 10
Figure 7 – Front and/or rear subrack and plug-in unit keying chamber inspection
dimensions . 10
Figure 8 – Alignment and/or electrical contact of a plug-in unit to a subrack . 11
Figure 9 – Alignment and/or electrical contact receptacle position in the subrack . 12
Figure 10 – Alignment and/or electrical contact interface inspection dimensions . 13
Figure 11 – Subrack guide rail and printed board, 2,54 mm offset of the printed board
reference plane . 14
Figure 12 – Dimensions of the subrack guide rail with 2,54 mm offset of the printed
board reference plane . 15
Figure 13 – Reference plane for printed boards with 2,54 mm offset position . 16

oSIST prEN IEC 60297-3-103:2026
IEC 60297-3-103 ED2 © IEC 2025

Table 1 – Subrack and plug-in unit keying chamber inspection dimensions . 10

oSIST prEN IEC 60297-3-103:2026
IEC 60297-3-103 ED2 © IEC 2025

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
Mechanical structures for electronic equipment - Dimensions of
mechanical structures of the 482,6 mm (19 in) series -
Part 3-103: Keying and alignment pin

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