IEC 60917-2-4:2010

IEC 60917-2-4 ®
Edition 1.0 2010-03
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Modular order for the development of mechanical structures for electronic
equipment practices –
Part 2-4: Sectional specification – Interface co-ordination dimensions for the
25 mm equipment practice – Adaptation dimensions for subracks or chassis
applicable in cabinets or racks in accordance with IEC 60297-3-100 (19 in)

Ordre modulaire pour le développement des structures mécaniques pour les
infrastructures électroniques –
Partie 2-4: Spécification intermédiaire – Dimensions de coordination pour les
interfaces des infrastructures au pas de 25 mm – Dimensions d’adaptation des
bacs ou des châssis, applicables dans les baies ou les bâtis, conformément à la
CEI 60297-3-100 (19 pouces)
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IEC 60917-2-4 ®
Edition 1.0 2010-03
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Modular order for the development of mechanical structures for electronic
equipment practices –
Part 2-4: Sectional specification – Interface co-ordination dimensions for the
25 mm equipment practice – Adaptation dimensions for subracks or chassis
applicable in cabinets or racks in accordance with IEC 60297-3-100 (19 in)

Ordre modulaire pour le développement des structures mécaniques pour les
infrastructures électroniques –
Partie 2-4: Spécification intermédiaire – Dimensions de coordination pour les
interfaces des infrastructures au pas de 25 mm – Dimensions d’adaptation des
bacs ou des châssis, applicables dans les baies ou les bâtis, conformément à la
CEI 60297-3-100 (19 pouces)
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
N
CODE PRIX
ICS 31.240 ISBN 978-2-88910-330-0
– 2 – 60917-2-4 © IEC:2010
CONTENTS
FOREWORD.3
INTRODUCTION.5
1 Scope and object.6
2 Normative references .6
3 Arrangement overview (Figure 1) and definitions .7
4 Dimensions for adaptor flanges of the specific metric subracks or chassis (suitable
only where W = 425 mm) mountable into 19 in cabinets or racks.8
S1
4.1 General .8
4.2 Dimensions for mounting holes arrangements on the adaptor flanges,
mounting layout referred to the bottom pitch lines of the metric subracks or
chassis.8
4.3 Dimensions for mounting holes arrangements on the adaptor flanges,
mounting layout referred to the unit centre lines of the metric subracks or
chassis.10
Bibliography.14

Figure 1 – Arrangement overview – Adaptation of specific subracks (aperture width for
plug-in units: W = 425 mm, 85 × 5,0 mm) of IEC 60917-2-4 into cabinets of
S1
IEC 60297-3-100 .7
Figure 2 – Mounting hole arrangements of the adaptor flanges, mounting layout
referred to the bottom pitch lines of the metric subracks or chassis.8
Figure 3 – Dimensions of mounting hole positions of the adaptor flanges, mounting
layout referred to the bottom pitch lines of the metric subracks or chassis .9
Figure 4 – Mounting hole arrangements on the adaptor flanges, mounting layout
referred to the unit centre lines of the metric subracks or chassis .11
Figure 5 – Dimensions of mounting holes positions of the adaptor flanges, mounting
layout referred to the unit centre lines of the metric subracks or chassis.12

Table 1 – Dimensions of mounting holes positions of the adaptor flanges, mounting
layout referred to the bottom pitch lines of the metric subracks or chassis .10
Table 2 – Dimensions of mounting holes positions of the adaptor flange, mounting
layout referred to the unit centre lines of the metric subracks or chassis.13

60917-2-4 © IEC:2010 – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
MODULAR ORDER FOR THE DEVELOPMENT
OF MECHANICAL STRUCTURES
FOR ELECTRONIC EQUIPMENT PRACTICES –

Part 2-4: Sectional specification –
Interface co-ordination dimensions for the 25 mm equipment practice –
Adaptation dimensions for subracks or chassis applicable in cabinets
or racks in accordance with IEC 60297-3-100 (19 in)

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,
Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC
Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested
in the subject dealt with may participate in this preparatory work. International, governmental and non-
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with the International Organization for Standardization (ISO) in accordance with conditions determined by
agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
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Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
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4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
services carried out by independent certification bodies.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 60917-2-4 has been prepared by subcommittee 48D: Mechanical
structures for electronic equipment, of IEC technical committee 48: Electromechanical
components and mechanical structures for electronic equipment.

– 4 – 60917-2-4 © IEC:2010
The text of this standard is based on the following documents:
FDIS Report on voting
48D/420/FDIS 48D/424/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
A list of all parts of IEC 60917 series, under the general title Modular order for the
development of mechanical structures for electronic equipment practices, can be found on the
IEC website.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
The committee has decided that the contents of this publication will remain unchanged until
the stability indicated on the IEC web site under "http://webstore.iec.ch" in the data related to
the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates
that it contains colours which are considered to be useful for the correct
understanding of its contents. Users should therefore print this document using a
colour printer.
60917-2-4 © IEC:2010 – 5 –
INTRODUCTION
The IEC 60917 series of standards provides definitions of mechanical structure and
dimensions for metric cabinets, racks, subracks, chassis and plug-in units based on metric
modular ordered dimensions. The later developed IEC 60917 series of standards, compared
to IEC 60297, provides more logical design practices based on metric dimensioning.
The IEC 60297 series of standards also define structures and interface dimensions for 19 in
cabinets, racks and their compatible subracks and chassis. Because of the longer history of
the IEC 60297 series of standards and their applications, the combination of 19 in based
cabinets, racks, subracks and chassis are broadly applied for all industrial electronic fields in
the world.
Requests for combined applications with both mechanical structures, the IEC 60917 series
(metric standard) and the IEC 60297 series (19 in standard), resulted in requirements to
mount metric subracks or chassis into 19 in standard cabinets or racks and, vice versa, 19 in
subracks or chassis into metric cabinets or racks.
To cope with the requirements and needs, it is required to develop definitions for appropriate
adaptation dimensions of flanges for metric or 19 in subracks or chassis to mount them into
cabinets or racks in accordance with 19 in or metric standard. And the definitions of
adaptation dimensions bring economical solutions for installations of electronic equipment into
existing cabinets or racks. Further, they provide guidance to electro-mechanical designers to
develop systems suitable to be mounted into both IEC standard series flexibly.
To meet such market needs, this standard defines adaptation dimensions for metric subracks
or chassis applicable for 19 in cabinets or racks. (Dimensions for the applications, where 19
in subracks or chassis are mounted on metric cabinets or racks, are defined in a separate
standard, i.e. IEC 60297-3-106.)

– 6 – 60917-2-4 © IEC:2010
MODULAR ORDER FOR THE DEVELOPMENT
OF MECHANICAL STRUCTURES
FOR ELECTRONIC EQUIPMENT PRACTICES –

Part 2-4: Sectional specification –
Interface co-ordination dimensions for the 25 mm equipment practice –
Adaptation dimensions for subracks or chassis applicable in cabinets
or racks in accordance with IEC 60297-3-100 (19 in)

1 Scope and object
This part of IEC 60917 specifies dimensions for mounting flanges of metric subracks or
chassis that are to be mounted into 19 in cabinets or racks.
Additional dimensions for subracks or chassis are according to the IEC 60917 series, and for
19 in cabinets or racks to the IEC 60297 series.
EMC, seismic climatic and environmental requirements and tests, are defined in the
IEC 61587 series.
The drawings used in this standard are not intended to indicate product design, only the
specific dimensions that shall be used.
The terminology used complies with IEC 60917-1.
2 Normative references
The following referenced documents are indispensable for the application 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 60297 (all parts), Mechanical structures for electronic equipment – Dimensions of
mechanical structures of the 482,6 mm (19 in) series
IEC 60297-3-100, Mechanical structures for electronic equipment – Dimensions of mechanical
structures of the 482,6 mm (19in) series – Part 3-100: Basic dimensions of front panels,
subracks, chassis, racks and cabinets
IEC 60297-3-106, Mechanical structures for electronic equipment – Dimensions of mechanical
structures of the 482,6 mm (19 in) series – Part 3-106: Adaptation dimensions for subracks
and chassis applicable to metric cabinets or racks in accordance with IEC 60917-2-1
IEC 60917 (all parts), Modular order for the development of mechanical structures for
electronic equipment practice
IEC 60917-2-2, Modular order for the development of mechanical structures for electronic
equipment practices – Part 2: Sectional specification – Interface co-ordination dimensions for
the 25 mm equipment practice – Section 2: Detail specification – Dimensions for subracks,
chassis, backplanes, front panels and plug-in units

60917-2-4 © IEC:2010 – 7 –
3 Arrangement overview (Figure 1) and definitions
This standard defines dimensions for adaptor flanges suitable for metric subracks or chassis
(aperture width for plug-in units: W = 425 mm, 85 × 5,0 mm) that are applicable for
S1
mounting into 19 in cabinets or racks.
Dimensions for applications where 19 in subracks or chassis are to be mounted into metric
cabinets or racks are defined in a separate standard (IEC 60297-3-106).
All other dimensions are in compliance with the IEC 60917 series (metric standard) and
IEC 60297 series (19 in standard).

465,1 ± 1,5
Cabinet in accrodance with
IEC 60297-3-100 (19 in)
Subrack in accrodance with
IEC 60917-2-2 (metric)
< 449
Support rail
85 × 5,0
465,1
Adaptor flange with 19 in hole-spacing
First pitch line
as an interface between the metric
subracks or chassis and the 19 in
cabinets or racks
IEC  458/10
Dimensions in mm
Figure 1 – Arrangement overview –
Adaptation of specific subracks (aperture width for plug-in units:
W = 425 mm, 85 × 5,0 mm) of IEC 60917-2-4 into cabinets of IEC 60297-3-100
S1
n × 25
Pitch line
n × 44,45
Pitch line in acxcordance
with IEC 60297-3-100
– 8 – 60917-2-4 © IEC:2010
4 Dimensions for adaptor flanges of the specific metric subracks or chassis
(suitable only where W = 425 mm) mountable into 19 in cabinets or racks
S1
4.1 General
Dimensions for mounting holes arrangements on the flanges are arranged by the two
mounting layouts in the cabinets:
a) Mounting layout referred to the pitch lines of the metric subracks or chassis, and
b) Mounting layout referred to the unit centre lines of the metric subracks or chassis.
4.2 Dimensions for mounting holes arrangements on the adaptor flanges, mounting
layout referred to the bottom pitch lines of the metric subracks or chassis
Figure 2 shows the mounting holes arrangements on the adaptor flanges.
Figure 3 and Table 1 show detailed dimensions of mounting holes positions of the adaptor
flange.
This mounting layout may be recommended for existing subracks or chassis with their support
rails utilized.
1) Use of the optional mounting position of the 19 in universal spacing Bottom pitch line
IEC  459/10
Dimensions in mm
Figure 2 – Mounting hole arrangements of the adaptor flanges, mounting layout referred
to the bottom pitch lines of the metric subracks or chassis

60917-2-4 © IEC:2010 – 9 –
Flange height: n × 25
IEC  460/10
Dimensions in mm
Figure 3 – Dimensions of mounting hole positions of the adaptor flanges, mounting
layout referred to the bottom pitch lines of the metric subracks or chassis

– 10 – 60917-2-4 © IEC:2010
Table 1 – Dimensions of mounting holes positions of the adaptor flanges, mounting
layout referred to the bottom pitch lines of the metric subracks or chassis
Dimensions in mm
System units F F F F
b1 b2 b3 b4
n × SU ± 0,4 ± 0,4 ± 0,4 ± 0,4
1SU 25 – – – –
a
2SU 50 15,88 – –
21,83
a
3SU 75 28,56 – –
21,83
4SU 100 37,70 28,56 – –
a
5SU 125 37,70 – –
57,15
6SU 150 37,70 88,90 – –
7SU 175 37,70 101,60 – –
8SU 200 37,70 133,35 – –
9SU 225 37,70 146,05 – –
10SU 250 37,70 177,80 – –
11SU 275 37,70 190,50 – –
12SU 300 37,70 88,90 57,15 88,90
13SU 325 37,70 88,90 57,15 88,90
14SU 350 37,70 101,60 76,20 101,60
15SU 375 37,70 101,60 76,20 101,60
16SU 400 37,70 88,90 146,05 88,90
17SU 425 37,70 88,90 146,05 88,90
18SU 450 37,70 133,35 101,60 133,35
19SU 475 37,70 101,60 209,55 101,60
20SU 500 37,70 101,60 209,55 101,60
21SU 525 37,70 146,05 165,10 146,05
22SU 550 37,70 101,60 254,00 101,60
23SU 575 37,70 133,35 234,95 133,35
24SU 600 37,70 133,35 234,95 133,35
a
Use of the optional mounting position of the 19 in universal spacing.

4.3 Dimensions for mounting holes arrangements on the adaptor flanges, mounting
layout referred to the unit centre lines of the metric subracks or chassis
Figure 4 shows the mounting holes arrangements on the adaptor flanges.
Figure 5 and Table 2 show detailed dimensions of mounting holes positions of the adaptor
flanges.
60917-2-4 © IEC:2010 – 11 –
Unit centre line
1) Use of the optional mounting position of the 19 in universal spacing
IEC  461/10
Dimensions in mm
Figure 4 – Mounting hole arrangements on the adaptor flanges, mounting layout
referred to the unit centre lines of the metric subracks or chassis

– 12 – 60917-2-4 © IEC:2010
Flange height: n × 25
Unit centre line
Unit centre line
Unit centre line
IEC  462/10
Dimensions in mm
Figure 5 – Dimensions of mounting holes positions of the adaptor flanges, mounting
layout referred to the unit centre lines of the metric subracks or chassis

60917-2-4 © IEC:2010 – 13 –
Table 2 – Dimensions of mounting holes positions of the adaptor flange, mounting
layout referred to the unit centre lines of the metric subracks or chassis
Dimensions in mm
System units F F F F
c1 c2 c3 c4
n × SU ± 0,4 ± 0,4 ± 0,4 ± 0,4
a
1SU 25 – – –
12,0
a
2SU 50 – – –
24,5
3SU 75 21,13 31,75 – –
4SU 100 20,93 57,15 – –
5SU 125 33,43 57,15 – –
6SU 150 45,93 57,15 – –
7SU 175 26,68 120,65 – –
8SU 200 26,48 146,05 – –
9SU 225 38,98 146,05 – –
10SU 250 51,48 146,05 – –
11SU 275 32,23 209,55 – –
12SU 300 32,03 88,90 57,15 88,90
13SU 325 44,53 88,90 57,15 88,90
14SU 350 25,28 120,65 57,15 120,65
15SU 375 25,08 101,60 120,65 101,60
16SU 400 37,58 88,90 146,05 88,90
17SU 425 50,08 101,60 120,65 101,60
18SU 450 30,83 133,35 120,65 133,35
19SU 475 30,63 146,05 120,65 146,05
20SU 500 43,13 133,35 146,05 133,35
21SU 525 23,88 165,10 146,05 165,10
22SU 550 23,68 146,05 209,55 146,05
23SU 575 38,18 133,35 234,95 133,35
24SU 600 48,68 133,35 234,95 133,35
a
Use of the optional mounting position of the 19 in universal spacing.

–
...