IEC 60297-3-108:2014

IEC 60297-3-108 ®
Edition 1.0 2014-09
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Mechanical structures for electronic equipment – Dimensions of mechanical
structures of the 482,6 mm (19 in) series –
Part 3-108: Dimensions of R-type subracks and plug-in units

Structures mécaniques pour équipements électroniques – Dimensions des
structures mécaniques de la série 482,6 mm (19 pouces) –
Partie 3-108: Dimensions des bacs de type R et des blocs enfichables

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IEC 60297-3-108 ®
Edition 1.0 2014-09
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Mechanical structures for electronic equipment – Dimensions of mechanical

structures of the 482,6 mm (19 in) series –

Part 3-108: Dimensions of R-type subracks and plug-in units

Structures mécaniques pour équipements électroniques – Dimensions des

structures mécaniques de la série 482,6 mm (19 pouces) –

Partie 3-108: Dimensions des bacs de type R et des blocs enfichables

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CODE PRIX U
ICS 31.240 ISBN 978-2-8322-1790-0

– 2 – IEC 60297-3-108:2014 © IEC 2014
CONTENTS
FOREWORD . 4
INTRODUCTION . 6
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 8
4 Arrangement overview . 8
5 RA – type subrack . 9
5.1 General . 9
5.2 RA–type subrack rear mounting dimensions . 11
6 RB–type subrack . 12
6.1 General . 12
6.2 RB–type subrack rear mounting dimensions . 13
7 R–type subrack guide rails . 13
8 Electromagnetic shielding provisions and mounting flanges . 14
9 Chassis integrated subrack . 15
9.1 General . 15
9.2 RA– C–type chassis/subrack . 16
9.3 RB–C–type chassis/subrack . 16
10 Front panel/plug-in unit compatible with RA – type subrack . 17
11 Front panel/plug-in unit compatible with RB – type subrack . 19
12 Injector/extractor handle . 20
13 Printed board dimensions . 20
14 Dimensions. 21
15 Nomenclature . 22
15.1 Reference plane (given in square boxes of figures) . 22
15.2 Dimensions of Table 1 . 22
Annex A (normative) Mounting support . 23
A.1 Chassis/subrack mounting support in cabinets . 23
Annex B (normative) Environmental tests. 24
B.1 Static and dynamic load test . 24
B.2 Seismic test . 24
B.3 Electromagnetic shielding performance test . 24
Annex C (normative) Thermal management . 25
C.1 Air ducting . 25
Annex D (informative) Comparison of IEC 60297-3-101 with IEC 60297-3-108 . 26

Figure 1 – Subrack application . 6
Figure 2 – Arrangement of a R-type subrack and plug-in units . 9
Figure 3 – RA–type subrack front mounting dimensions . 10
Figure 4 – RA–type subrack rear mounting dimensions . 11
Figure 5 – RB–type subrack front mounting dimensions . 12
Figure 6 – RB–type subrack rear mounting dimensions . 13
Figure 7 – R–type subrack guide rails . 14

Figure 8 – R–type subrack front attachment plane and mounting flanges . 15
Figure 9 – RA – C type chassis/subrack . 16
Figure 10 – RB–C – type chassis/subrack . 17
Figure 11 – Front panel/ plug-in unit compatible with RA – type subrack . 18
Figure 12 – Front panel/ plug-in unit compatible with RB – type subrack . 19
Figure 13 – Injector/extractor handle . 20
Figure 14 – Printed board dimensions . 21
Figure A.1 – Subrack/chassis mounting support . 23
Figure C.1 – Thermal management example . 25

Table 1 – Dimensions . 21
Table D.1 – Comparison of dimensions and features . 26

– 4 – IEC 60297-3-108:2014 © IEC 2014
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
MECHANICAL STRUCTURES
FOR ELECTRONIC EQUIPMENT –
DIMENSIONS OF MECHANICAL STRUCTURES
OF THE 482,6 mm (19 in) SERIES –

Part 3-108: Dimensions of R-type subracks and plug-in units

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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4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
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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
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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
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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 60297-3-108 has been prepared by subcommittee 48D:
Mechanical structures for electronic equipment, of IEC technical committee 48: Electrical
connectors and mechanical structures for electrical and electronic equipment.
The text of this standard is based on the following documents:
FDIS Report on voting
48D/565/FDIS 48D/570/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.

This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all parts of IEC 60297 series, under the general title Mechanical structures for
electronic equipment – Dimensions of mechanical structures of the 482,6 mm (19 in) series
can be found on the IEC website.
The committee has decided that the contents of this publication will remain unchanged until
the stability date 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.
– 6 – IEC 60297-3-108:2014 © IEC 2014
INTRODUCTION
The purpose of this standard is to establish alternative dimensions and features for subracks
and associated plug-in units, compared with IEC 60297-3-101. These alternatives allow more
sturdy designs for the load bearing members of the subrack. In addition, the plug-in units are
with alignment pins and fastened with M3 screws. Chassis integrated subracks are also part
of this standard.
The main differing dimensions/features compared with IEC 60297-3-101 are:
a) The subrack height aperture is decreased in order to increase the dimension for the top
and bottom members (most critical load bearing parts).
b) Incorporated alignment between the subrack and the plug-in units. Injecting and extracting
provisions for plug-in units.
c) The mounting flanges of the subracks are recessable. This feature meets the mounting
requirements of heavy subracks and allows the positioning to the centre of gravity.
d) Chassis integrated subracks for optimized thermal management features.
e) Comparison of dimensions and features with IEC 60297-3-101 is shown in appendix D,
Table D.1. For an application image of the subrack based on this standard see Figure 1.

IEC 60297-3-101
Conventional form factor
and normal weight, for small to medium
volume applications, e.g. general industrial
computing and data processing
IEC 60297-3-107 IEC 60297-3-108
Small form factor and light weight, Heavy weight and large form
for large volume applications, e.g. factor, for large volume
embedded systems, applications, e.g. cloud-
mobile/ubiquitous computing computing servers, telecom
systems servers
Embedded system Full scaled 19 in system Heavy duty 19 in system
Subrack and plug-in unit system weight factor
IEC
Figure 1 – Subrack application

Subrack and plug-in unit
mechanical complexity factor
Low High
MECHANICAL STRUCTURES
FOR ELECTRONIC EQUIPMENT –
DIMENSIONS OF MECHANICAL STRUCTURES
OF THE 482,6 mm (19 in) SERIES –

Part 3-108: Dimensions of R-type subracks and plug-in units

1 Scope
This part of IEC 60297 provides dimensions and features for R-type subracks and plug-in
units, i.e. ruggedized variants of the mechanical structures of the 482,6 mm (19 in) series,
with enhanced vibration and shock resistance and/or improved EMC performance, for use in
more harsh environment. This leads to a subrack standard which is externally compatible with
IEC 60297-3-100 but internally largely incompatible with IEC 60297-3-101. R-type subracks,
chassis integrated subracks and plug-in units incorporate dimensions and features which
provide for a higher level of ruggedness, compared with IEC 60297-3-101 (test set-up and
load definitions are selected from IEC 61587-1 and IEC 61587-5).
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and
are indispensable for its application. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any
amendments) applies.
IEC 60297-3-100, Mechanical structures for electronic equipment – Dimensions of mechanical
structures of the 482,6 mm (19 in) series – Part 3-100: Basic dimensions of front panels,
subracks, chassis, racks and cabinets
IEC 60297-3-101, Mechanical structures for electronic equipment – Dimensions of mechanical
structures of the 482,6 mm (19 in) series – Part 3-101: Subracks and associated plug-in units
IEC 60297-3-105, Mechanical structures for electronic equipment – Dimensions of mechanical
structures of the 482,6 mm (19 in) series – Part 3-105: Dimensions and design aspects for 1U
high chassis
IEC 61587-1, Mechanical structures for electronic equipment – Tests for IEC 60917 and
IEC 60297 series – Part 1: Environmental requirements, test set-up and safety aspects for
cabinets, racks, subracks and chassis under indoor conditions
IEC 61587-3, Mechanical structures for electronic equipment – Tests for IEC 60917 and
IEC60297 – Part 3: Electromagnetic shielding performance tests for cabinets and subracks
IEC 61587-5, Mechanical structures for electronic equipment – Tests for IEC 60917 and
IEC 60297 – Part 5: Seismic tests for chassis, subracks, and plug-in units
IEC TS 62610-2, Mechanical structures for electronic equipment – Thermal management for
cabinets in accordance with IEC 60297 and IEC 60917 series – Part 2: Design guide: Method
for determination of forced air-cooling structure

– 8 – IEC 60297-3-108:2014 © IEC 2014
3 Terms and definitions
For the purposes of this document the following terms and definitions apply.
3.1
R–type subrack and plug–in unit
ruggedized subrack and plug-in unit, with enhanced shock and vibration resistance, with or
without EMC provisions compared with subrack/plug-in units according to IEC 60297-3-101
3.2
chassis integrated subrack
subrack integrated within the envelope of a chassis
4 Arrangement overview
Figure 2 illustrates the typical arrangement of a R-type subrack with the associated plug-in
units.
Optional, additional
receptacle for
Injector/extractor handle
Mounting flange with
mounting dimensions
according to
IEC 60297-3-101
Mandatory receptacle
for injector/extractor
handle
Front panel
Plug-in unit with
injector/extractor handle
IEC
Figure 2 – Arrangement of a R-type subrack and plug-in units
5 RA – type subrack
5.1 General
Figure 3 illustrates the RA-type subrack, defined by the dimension of the first printed board
position in relation to the first pitch line (see detail A). The deflection of the load bearing
members of max. 0,2 mm is permitted.

– 10 – IEC 60297-3-108:2014 © IEC 2014

Dimensions in millimetres,
Front view
tolerances are non-cumulative
≥ 431,80
C D
84 x 5,08 = 426,72
5,08
B
A
G
G
G
A
≤ 449,0 (including fixing hardware)
Detail A
J
Ø4,0 ± 0,1 x 3,2 ± 0,1 receptacle holes
1)
(4,27) 9,7 ± 0,2
for front panel alignment pins
on lower and upper horizontal member
First printed
I
board position
A
G
H
A
M3
6,35 ± 0,1
(see A – A)
1)
1)
Cross-section
13,97 ± 0,1
20,32 ± 0,1
≥ 2, 54
A - A
First pitch line
E
A
2)
1,5 ± 0,2 M3
Min 2,0
R 1,5
Max 1,5
9,5 ± 0,2
IEC
Key
1 If this dimension needs to be increased increments of 5,08mm shall be used, based on the dimension
4,07 mm as in IEC 60297-3-101.
2 May be applied by press-in nuts.
Figure 3 – RA–type subrack front mounting dimensions
n x U
H 6
5,5 + 0/-0,5
H 5
0,2  D
H 6
0,2  G
H 1
5.2 RA–type subrack rear mounting dimensions
Figure 4 illustrates the rear mounting dimensions with the possible mounting holes for
backplanes.
Dimensions in millimetres,
tolerances are non-cumulative
Rear view
84 x 5,08 = 426,72
First pitch line
82 x 5,08 = 416,56
5,08
B
M3 threaded holes
shall be applied for
backplane mounting
C
D
≥ 2,54
First possible backplane
B
mounting position M3
J
(4,27)
B
A
Cross-section B - B
0,2    E
F
E
D 1
IEC
Figure 4 – RA–type subrack rear mounting dimensions
n x U
H 6
H 1
n x U
H 6
– 12 – IEC 60297-3-108:2014 © IEC 2014
6 RB–type subrack
6.1 General
Figure 5 illustrates the subrack RB-type, defined by the dimension of the first printed board
position in relation to the first pitch line (see Detail B). The deflection of the load bearing
members of max. 0,2 mm is permitted.

Dimensions in millimetres,
Front view
tolerances are non-cumulative
≥ 431,80
C
D
84 x 5,08 = 426,72
5,08
B
A
G
B
≤ 449,0 (including fixing hardware)
Detail B
J
Ø4,0 ± 0,1 x 3,2 ± 0,1 receptacle holes for front
7,16 ± 0,2
panel alignment pins
1)
(6,81)
on lower and upper horizontal member.
First printed board
position
G
C
C
Cross-section
C - C
6,35 ± 0,1
C M3 (see C – C)
1)
1)
13,97± 0,1
20,32 ± 0,1
≥ 2, 54
E
First pitch line
2)
M3
A
1,5 ± 0,2
Min 2,0
R 1,5
9,5 ± 0,2
Max 1,5
IEC
Key
1 If this dimension needs to be increased increments of 5,08 mm shall be used, based on the dimension
4,07 mm as in IEC 60297-3-101.
2 Press-in nuts may be applied.
Figure 5 – RB–type subrack front mounting dimensions
n x U
H6
5,5 + 0/-0,5
H 5
0,2  D
H 6
0,2  G
H 1
6.2 RB–type subrack rear mounting dimensions
Figure 6 illustrates the rear mounting dimensions with the possible mounting holes for
backplanes.
Dimensions in millimetres,
tolerances are non-cumulative
Rear view
84 x 5,08 = 426,72
82 x 5,08 = 416,56
First pitch line
D 5,08
M3 threaded holes
shall be applied for
backplane mounting
C
D
≥ 2,54
First possible backplane
mounting position M3
D
J
(6,81)
B
A
Cross-section D - D
0,2  E
E F
D 1
IEC
Figure 6 – RB–type subrack rear mounting dimensions
7 R–type subrack guide rails
The position of guide rails (Figure 7) is always in relation to the receptacle holes for the
alignment pin of the plug-in unit (as shown in Figures 3 and 5, Details A and B).
n x U
H 6
H 1
n x U
H 6
– 14 – IEC 60297-3-108:2014 © IEC 2014
Dimensions in millimetres,
tolerances are non-cumulative
Front view
E E
3)
Cross-section E - E
F
2,8 ± 0,1
E
≥ 30 °
First pitch line
IEC
Key
1 Dimension D 1 and D 2 depend on printed board depth and connector type.
2 Position of an optional ESD contact, connecting both sides of the printed board (ESD = Electrostatic discharge).
3 First guide rail on left.
Figure 7 – R–type subrack guide rails
8 Electromagnetic shielding provisions and mounting flanges
Figure 8 illustrates the subrack front mounting plane with the conductive areas for the
attachment of front panels and the vertical connection at the left and right side panels. The
electromagnetic shielding provisions (EMC: Electromagnetic Compatibility) at the rear of the
subrack may be resolved by backplanes and/or user defined covers. For EMC shielding
performance test see IEC 61587-3.
The mounting flanges may be recessed by n × 25 mm.
1)
D 1
1)
D 2
≥ 13 ,0
2)
10 ± 1,0
3,0 + 0/-0,2 3,0 + 0/-0,2
2)
30 ± 1
Dimensions in millimetres,
Front view
tolerances are non-cumulative
Missing dimensions, see IEC 60297-3-101
Conductive surface
F
F
482,6 ± 0,4
Top view
Cross-section F - F
First pitch line
n x 5,08
Conductive
EMC gasket
surface
C
Uncompressed
gasket
0,3 ± 0,1
min 0,5 mm
max 1,3 mm
Detail “C“
Mounting flanges may be
recessed by n x 25 mm.
IEC
Figure 8 – R–type subrack front attachment plane and mounting flanges
9 Chassis integrated subrack
9.1 General
Chassis integrated subracks are common for electronic equipment where air ducting, cooling
devices or space for cabling are incorporated into one mechanical unit.
5,0 ± 0,5
(n x 25)
≥ 10,0
– 16 – IEC 60297-3-108:2014 © IEC 2014
9.2 RA– C–type chassis/subrack
The RA–C type chassis/subrack, in which RA – type subrack is integrated, defines the chassis
dimensions (see Figure 9).
Dimensions in millimetres,
Front view
tolerances are non-cumulative
2)
(4,27)
First pitch line
IEC
Key
1 Chassis height reduced for the mounting of chassis supports (see Annex A).
2 First guide rail position (see Figure 2).
Figure 9 – RA – C type chassis/subrack
9.3 RB–C–type chassis/subrack
The RB–C–type chassis/subrack, in which RB–type subrack is integrated, defines the chassis
dimensions (see Figure 10). The subrack may be placed asymmetrically within the chassis
dimensions. For chassis overall dimensioning see IEC 60297-3-105 (plus n × 1U).
H 1
1)
U – (3,0 + 0,5/-0)
n x 44,45 = U
Front view
2)
(6,81)
First pitch line
IEC
Key
1 Chassis height reduced for the mounting of chassis supports (see Annex A).
2 First guide rail position (see Figure 4).
Figure 10 – RB–C – type chassis/subrack
10 Front panel/plug-in unit compatible with RA – type subrack
Figure 11 illustrates the frontpanel/plug-in unit compatible with RA–type subrack and the
position of a printed board.
H 1
1)
U – (3,0 + 0/-0,5)
n x 44,45 = U
– 18 – IEC 60297-3-108:2014 © IEC 2014

Front view
Dimensions in millimetres,
tolerances are non-cumulative
2)
G
10.82 ± 0,1
2)
2,9 ± 0,1
Cross-section H - H
Optional EMC
6,35 ± 0,1
gasket
Ø3 ± 0,05
≤ 1,0
10,0 ± 0,2
≤ 1,0
Alignment pin ≤ 13,5
max 5 fastened
≤ 0,0 unfastened 1,0 ± 0,1
H M3
H
Uncompressed gasket
min 0,5 mm
13,97 ± 0,1
max 1,3 mm
1)
(0,15) 19,72 ± 0,1 (0,67)
Pitch line
1)
20,32
G
Top view
Cross-section G - G
Connector user
defined
Printed board
component side 2
Printed board
7,0 ± 0,1
component side 1
12,5 ± 0,2
(optional)
Optional cover
M 2,5
(4,07)
9,7 ± 0,1
6,0 ± 0,1 (optional)
3)
Pitch line
13,97 ± 0,1
4,0 ± 0,1
Alternative front
1)
panel design
(0,15) 18,72 ± 0,1
IEC
Key
1 May be increased by n x 5,08 mm
2 Optional cut outs if injector/extractor handles are used
3 Retention screw float +/- 0,5 mm
Figure 11 – Front panel/ plug-in unit compatible with RA – type subrack
H 8
Conductive
H 6
surface
2) 2)
11,0 -± 0,2
11,0 -± 0,2
H5 -2,35 ± 0,2
6,0 ± 0,1
≤ 2,5
5,0 ± 0,5
H5 -8,35 ± 0,1
11 Front panel/plug-in unit compatible with RB – type subrack
Figure 12 illustrates the frontpanel/plug-in unit compatible with RB–type subrack and the
position of a printed board.
Front view Dimensions in millimetres,
tolerances are non-cumulative
2)
10,82 ± 0,1
2)
2,9 ± 0,1
Cross-section K - K
Optional EMC
6,35 ± 0,1
Ø3 ± 0,05
gasket
≤ 1,0
≤ 1,0
J 10,0 ± 0,2
Alignment pin
≤ 13,5
max 5 fastened
1,0 ± 0,1
≤ 0,0 unfastened
M3
Uncompressed gasket
K K
min 0,5
13,97 ± 0,1 max 1,3
1)
(0,15) 19,72 ± 0,1 (0,67)
Pitch line
1)
20,32
J
Cross-section J - J
Top view
Connector user
defined
Printed board
7,0 ± 0,1
component side 2
12,5 ± 0,2
Printed board
(optional)
component side 1
Optional cover
M 2,5
6,0 ± 0,1 (optional)
3)
(6,61)
7,16 ± 0,1
4,0 ± 0,1
Pitch line
13,97 ± 0,1
Alternative frontpanel
design
1)
18,72 ± 0,1
(0,15)
IEC
Key
1 May be increased by n x 5,08 mm
2 Optional cut outs if injector/extractor handles are used
3 Retention screw float +/- 0,5 mm
Figure 12 – Front panel/ plug-in unit compatible with RB – type subrack
H 8
Conductive
surface
H 6
2)
2)
11,0 ± 0,2 11,0 ± 0,2
H5 -2,35 ± 0,2
≤ 2,5
6,0 ± 0,1
5,0 ± 0,5
H5 -8,35 ± 0,1
– 20 – IEC 60297-3-108:2014 © IEC 2014
12 Injector/extractor handle
Figure 13 illustrates the injector/extractor handle. The max. single handle lever dimension is
due to connector forces of max. 350 N. Handle lever for higher connector forces shall be
agreed between supplier and user. The minimal travel of the handle for extraction/insertion
shall be 7,5 mm. Even if the handle may be with a self-locking function, the reliable fastening
of front panels shall be resolved by screws M3. As shown in Figure 13, the handle lever
direction may be vertical or horizontal.

Dimensions in millimetres,
tolerances are non-cumulative
Side view
Injector/extractor handle
position within the subrack
G
max 40
Alternative handle lever design,
horizontal
(2,0)
Front view
G
11,0 ± 0,5
Side view
Handle details
Max 3,0
Retention screw
2,0 ± 0,1
2,0 ± 0,1
Pivot point
Ø2,0
15,0 ± 0,2
Ø4,0
Ø4,0
(0,36) 18,0 ± 0,2
5,0 ± 0,1
Pitch line
IEC
Figure 13 – Injector/extractor handle
13 Printed board dimensions
Figure 14 illustrates the printed board dimensions.
10,0 ± 0,1
9,0 ± 0,1
max 40
6,5 ± 0,1
(13,5)
Dimensions in millimetres,
tolerances are non-cumulative
D 3
3,6 ± 0,1
6,0 ± 0,1
OptionalOpt ional holes
holes Ø 2,7
2)
1)
≥13,5
IEC
Key
1 Keep out area for frontpanel attachment and components.
2 Printed board thickness 1,4 – 2,6 mm.
Figure 14 – Printed board dimensions
14 Dimensions
Table 1 contains the dimensions of subracks and plug-in units.
Table 1 – Dimensions
Dimensions in millimetres
Height units U H1 H5 H6 H8 H10
(n × 44,45) ± 0,4 ± 0,2 ± 0,2 ± 0,2 + 0/- 0,3
3U
132,55 100,35 113,55 119,55 100,00
(133,35)
4U
177,00 144,80 158,00 164,00 144,45
(177,80)
5U
221,45 189,25 202,45 208,45 188,90
(222,25)
6U
265,90 233,70 246,90 252,90 233,35
(266,70)
7U
310,35 278,15 291,35 297,35 277,80
(311,15)
8U
354,80 322,60 335,80 341,80 322,25
(355,60)
9U
399,25 367,05 380,25 386,25 366,70
(400,05)
NOTE The dimensions H1 and H10 comply with IEC 60297-3-101.

H 10
H 10 -8,0 ± 0,1
(4,0)
Ø 2,7 ± 0,1
1)
1)
≥7,5
≥7,5
1)
≥7,5
1)
1)
≥3,5 ≥3,5
– 22 – IEC 60297-3-108:2014 © IEC 2014
15 Nomenclature
15.1 Reference plane (given in square boxes of figures)
A  First pitch line
B  Last pitch line
C  Left side plate
D  Right side plate
E  Front attachment plane
F  Rear attachment plane
G  Subrack height aperture
H  Position of receptacle holes for M3
I  Position of alignment pin receptacle hole
J  Guide rail reference line for printed boards and two part connectors
15.2 Dimensions of Table 1
Height
U: Coordination height unit of 44,45 mm (1,75 in). See IEC 60297-3-100.
H1: Subrack heights (equal to dimension E of IEC 60297-3-100).
H5: Subrack vertical aperture for plug-in units
H6: Mounting centre distance for front plug-in units and panels, front and rear.
H8: Plug-in unit panel height.
H10: Printed board height into subrack guidance height.
Width
HP: The subrack aperture is theoretically divided into n × horizontal pitches (HP) of
5,08 mm.
The plug-in unit front panel width is divided into n × 5,08 mm horizontal pitches.
Depth
D1: Subrack dimension between front attachment plane and backplane attachment plane.

Annex A
(normative)
Mounting support
A.1 Chassis/subrack mounting support in cabinets
Figure A.1 illustrates the mounting of a chassis with integrated subrack into a cabinet using
mounting supports for heavy load and/or in case of dynamic stress.
Example of a chassis with
integrated subrack
(see Figures 8 and 9).
max 2,0
Chassis mounting support
fixed to the cabinet uprights
(see IEC 60297-3-100)
IEC
Figure A.1 – Subrack/chassis mounting support
U–3,0+0,5/-0
– 24 – IEC 60297-3-108:2014 © IEC 2014
Annex B
(normative)
Environmental tests
B.1 Static and dynamic load test
For the proof of mechanical integrity the chassis/subrack loaded with plug-in units should be
tested in accordance with IEC 61587-1 (static load, vibration and shock).
B.2 Seismic test
In case of seismic requirements the chassis/subrack loaded with plug-in units should be
tested in accordance with IEC 61587-5 (resistance of the mechanical structure against
seismic impact).
B.3 Electromagnetic shielding performance test
In case of EMC requirements (electromagnetic compatibility) the chassis/subrack and plug-in
units should be tested in accordance with IEC 61587-3 (shielding performance level of the
mechanical design).
Annex C
(normative)
Thermal management
C.1 Air ducting
Figure C.1 illustrates a chassis with integrated subrack. The air ducting shall be from the front
inlet 2), distributed across the depth, vertical up through the subrack 1) and out at the rear 3).
The lower and upper compartments are adding to the height dimension of the subrack n × U,
dependent on the air volume or for the accommodation of fans. The air ducting from front to
rear is the preferred solution in accordance with IEC TS 62610-2.

3)
Air out
1)
2)
Air in
IEC
Key
1) Subrack with plug-in units
2) Compartment with louvered front for air inlet
3) Compartment with louvered rear for air outlet
Figure C.1 – Thermal management example

– 26 – IEC 60297-3-108:2014 © IEC 2014
Annex D
(informative)
Comparison of IEC 60297-3-101 with IEC 60297-3-108

Table D.1 – Comparison of dimensions and features
Comparative points IEC 60297-3-101 IEC 60297-3-108
Subrack Subrack R-type
Compatible with Incompatible with
Subrack dimensions (mm)
IEC 60297-3-101 IEC 60297-3-101
H1: Subrack heights n × 44,45 – 0,80 Yes –
H5: Subrack vertical aperture opening for –
n × 44,45 – 21,35 n × 44,45 – 33,00
plug-in units.
H6: Mounting centre distance for plug-in n × 44,45 – 10,85 – n × 44,45 -19,80
units, front panels, backplanes and
connector supports.
H8: Plug-in unit front panel height. –
n × 44,45 – 4,80 n × 44,45 – 13,80
H10: Printed board height or plug-in unit Yes –
n × 44,45 – 33,35
into subrack guidance height.
Subrack aperture definitions (HP) Yes –
n × 5,08
Subrack depth (D1 – D4, RD1, RD3 and ------ Yes –
RD4)
Other subrack features
Fixing screws for plug-in units, front M 2,5 – M 3
panels, backplanes and connector
supports.
Alignment pins for plug-in units Auxiliaries – Yes
according to
IEC 60297-3-103
Front panels for plug-in units ------ – Yes
Positions of fixing holes for front panel ------ – Yes
Printed board mounting to front panel, 88,90 + n × 44,45 - H 10 – 8,0
vertical
Printed board mounting to front panel, 2,54 + 3,57 = 6,11 - 4,0
horizontal
EMC provisions ------ – Yes
Injector/extractor handle for plug-in units Auxiliaries – Yes
according to
IEC 60297-3-102
Subrack mounting flanges ------ May be recessed by –
n × 25 mm
(Rear mount
supports can be
arranged)
_____________
– 28 – IEC 60297-3-108:2014 © IEC 2014
SOMMAIRE
AVANT-PROPOS . 30
INTRODUCTION . 32
1 Domaine d'application . 33
2 Références normatives . 33
3 Termes et définitions . 34
4 Vue d'ensemble de la disposition . 34
5 Bac de type RA . 35
5.1 Généralités . 35
5.2 Dimensions de montage arrière d'un bac de type RA . 37
6 Bac de type RB . 38
6.1 Généralités . 38
6.2 Dimensions de montage arrière d'un bac de type RB . 39
7 Rails de guidage d'un bac de type R . 39
8 Dispositions pour blindage électromagnétique et brides de montage . 40
9 Bac intégré au châssis . 41
9.1 Généralités . 41
9.2 Châssis/bac de type RA-C . 42
9.3 Châssis/bac de type RB-C . 42
10 Panneau avant/bloc enfichable compatibles avec un bac de type RA . 43
11 Panneau avant/bloc enfichable compatibles avec un bac de type RB . 45
12 Poignée d'insertion/extraction . 46
13 Dimensions de la carte imprimée . 46
14 Dimensions. 47
15 Nomenclature . 48
15.1 Plan de référence (donné dans les cases carrées des figures) .
...