IEC 60794-2-20:2024

IEC 60794-2-20 ®
Edition 4.0 2024-12
REDLINE VERSION
INTERNATIONAL
STANDARD
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Optical fibre cables –
Part 2-20: Indoor cables – Family specification for multi-fibre optical cables

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IEC 60794-2-20 ®
Edition 4.0 2024-12
REDLINE VERSION
INTERNATIONAL
STANDARD
colour
inside
Optical fibre cables –
Part 2-20: Indoor cables – Family specification for multi-fibre optical cables
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 33.180.01 ISBN 978-2-8327-0104-1

– 2 – IEC 60794-2-20:2024 RLV © IEC 2024
CONTENTS
FOREWORD . 4
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 7
4 Construction . 7
4.1 General . 7
4.2 Optical fibres . 8
4.3 Buffer . 8
4.4 Ruggedized fibre . 8
4.5 Slotted core . 8
4.6 Tube . 9
4.7 Stranded tube . 9
4.8 Ribbon structure . 9
4.9 Strength and anti-buckling members . 9
4.10 Ripcord . 9
4.11 Sheath . 9
4.12 Sheath marking . 9
4.13 Identification . 9
4.14 Examples of cable constructions . 10
5 Tests . 10
5.1 General . 10
5.2 Dimensions . 10
5.3 Mechanical requirements . 10
5.3.1 CableTensile performance . 10
5.3.2 CableCrush . 11
5.3.3 CableImpact . 11
5.3.4 CableBending . 11
5.3.5 CableRepeated bending . 12
5.3.6 CableBending under tension . 12
5.3.7 CableBending at low temperature . 12
5.3.8 CableFlexing . 12
5.3.9 CableTorsion . 12
5.3.10 Cable Kink . 13
5.4 Environmental requirements – Temperature cycling . 13
5.5 Transmission requirements . 14
5.5.1 General . 14
5.5.2 Single-mode optical fibres . 14
5.5.3 Single-mode dispersion unshifted (B-652.B) optical fibre . 14
5.5.4 Single-mode dispersion unshifted (B-652.D) optical fibre . 15
5.5.5 Single-mode (B-657.A) optical fibre . 15
5.5.6 Single-mode (B-657.B) optical fibre . 15
5.5.7 Multimode optical fibres . 15
5.5.8 Multimode (A1-OM1 to A1-OM5) optical fibres . 16
5.6 Fire performance . 16
Annex A (informative) Examples of cable constructions . 17
Annex B (informative) Family specification for multi-fibre optical cables – Blank detail
specification and minimum requirements . 22

B.1 Blank detail specification . 22
B.1.1 General . 22
B.1.2 Cable description . 22
B.1.3 Cable element . 23
B.1.4 Cable construction . 24
B.1.5 Installation and operating conditions . 25
B.1.6 Mechanical and environmental tests . 25
B.2 Cables subject to the MICE environmental classification (ISO/IEC 11801-1
and related standards) . 26
Bibliography . 27

Figure A.1 – Example of cross-section of a 12-fibre cable . 17
Figure A.2 – Example of cross-section of a 36-fibre cable . 17
Figure A.3 – Example of cross-section of a 6-fibre break-out cable . 18
Figure A.4 – Example of cross-section of a 24-fibre break-out cable . 18
Figure A.5 – Example of cross-section of a slotted core type indoor cable with 4-fibre
ribbons . 19
Figure A.6 – Example of cross-section of an SZ (reverse oscillating lay) slotted core
type indoor cable with 2-fibre ribbons . 19
Figure A.7 – Example of cross-section of an SZ (reverse oscillating lay) slotted core
type indoor cable with 4-fibre bundles . 20
Figure A.8 – Example of multi-fibre unitube cable . 20
Figure A.9 – Example of multi-fibre cable . 20
Figure A.10 – Example of a retractable (micro-module) cable . 21

Table 1 – Dimensions of buffered fibres . 8
Table 2 – Sample temperature cycling values .
Table 2 – Typical values for temperature cycling . 13
Table 3 – Common single-mode optical fibre requirements . 14
Table 4 – Cabled fibre attenuation requirements for B-652.B optical fibre . 14
Table 5 – Cabled fibre attenuation requirements for B-652.D optical fibre . 15
Table 6 – Cabled fibre attenuation requirements for B-657.A optical fibre . 15
Table 7 – Cabled fibre attenuation requirements for B-657.B optical fibre . 15
Table 8 – Common multimode optical fibre requirements . 15
Table 9 – Cabled fibre attenuation requirements for A1-OM1 to A1-OM5 optical fibres . 16
Table B.1 – Cable description . 22
Table B.2 – Cable element . 23
Table B.3 – Cable construction . 24
Table B.4 – Installation and operating conditions . 25
Table B.5 – Tests applicable . 25

– 4 – IEC 60794-2-20:2024 RLV © IEC 2024
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
OPTICAL FIBRE CABLES –
Part 2-20: Indoor cables –
Family specification for multi-fibre optical cables

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,
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preparation is entrusted to technical committees; any IEC National Committee interested in the subject dealt with
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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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5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
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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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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) IEC draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). IEC takes no position concerning the evidence, validity or applicability of any claimed patent rights in
respect thereof. As of the date of publication of this document, IEC had not received notice of (a) patent(s), which
may be required to implement this document. However, implementers are cautioned that this may not represent
the latest information, which may be obtained from the patent database available at https://patents.iec.ch. IEC
shall not be held responsible for identifying any or all such patent rights.
This redline version of the official IEC Standard allows the user to identify the changes
made to the previous edition IEC 60794-2-20:2013. A vertical bar appears in the margin
wherever a change has been made. Additions are in green text, deletions are in
strikethrough red text.
IEC 60794-2-20 has been prepared by subcommittee 86A: Fibres and cables, of IEC technical
committee 86: Fibre optics. It is an International Standard.
This fourth edition cancels and replaces the third edition published in 2013. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) update of the normative references;
b) review update of parameters and requirements for mechanical tests and environmental
tests, maintaining alignment with additional relevant standards in the IEC 60794-2 series;
c) addition of cabled fibre attenuation requirements;
d) addition of cable design examples.
This document is to be used in conjunction with IEC 60794-1-1:2023, IEC 60794-1-2:2021,
IEC 60794-1-21:2015 and IEC 60794-1-21:2015/AMD:2020, IEC 60794-1-22:2017,
IEC 60794-1-23:2019 and IEC 60794-2:2017.
The text of this International Standard is based on the following documents:
Draft Report on voting
86A/2431/FDIS 86A/2520/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 of IEC 60794 series, published under the general title Optical fibre cables, 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.
IMPORTANT – The "colour inside" logo on the cover page of this document 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 60794-2-20:2024 RLV © IEC 2024
OPTICAL FIBRE CABLES –
Part 2-20: Indoor cables –
Family specification for multi-fibre optical cables

1 Scope
This part of IEC 60794 is a family specification covering multi-fibre optical cables for indoor
use. The requirements of the sectional specification IEC 60794-2 are applicable to cables
covered by this document. Annex B contains a blank detail specification and general guidance
in case the cables are intended to be used in installations governed by the MICE table of
ISO/IEC 24702 (Industrial premises) [11] ISO/IEC 11801-1.
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.
NOTE These reference complete the normative references already listed in the generic specification (IEC 60794-1-
1 and IEC 60794-1-2).
IEC 60189-1, Low-frequency cables and wires with PVC insulation and PVC sheath – Part 1:
General test and measuring methods
IEC 60304, Standard colours for insulation for low-frequency cables and wires
IEC 60793-1-20, Optical fibres – Part 1-20: Measurement methods and test procedures – Fibre
geometry
IEC 60793-1-21, Optical fibres – Part 1-21: Measurement methods and test procedures –
Coating geometry
IEC 60793-1-40, Optical fibres – Part 1-40: Attenuation measurement methods
IEC 60793-1-44, Optical fibres – Part 1-44: Measurement methods and test procedures – Cut-
off wavelength
IEC 60793-1-46, Optical fibres – Part 1-46: Measurement methods and test procedures –
Monitoring of changes in optical transmittance
IEC 60793-2-10, Optical fibres – Part 2-10: Product specifications – Sectional specification for
category A1 multimode fibres
IEC 60793-2-50, Optical fibres – Part 2-50: Product specifications – Sectional specification for
class B single-mode fibres
IEC 60794-1-1:2023, Optical fibre cables – Part 1-1: Generic specification – General
___________
Figures in square brackets refer to the Bibliography.

IEC 60794-1-2:2021, Optical fibre cables – Part 1-2: Generic specification – Basic optical cable
test procedures – General guidance
IEC 60794-1-20, Optical fibre cables – Part 1-20: Generic specification – Basic optical cable
test procedures – General and definitions
IEC 60794-1-21:2015, Optical fibre cables – Part 1-21: Generic specification – Basic optical
cable test procedures – Mechanical test methods
IEC 60794-1-21:2015/AMD1:2020
IEC 60794-1-22:2017, Optical fibre cables – Part 1-22: Generic specification – Basic optical
cable test procedures – Environmental test methods
IEC 60794-1-23:2019, Optical fibre cables – Part 1-23: Generic specification – Basic optical
cable test procedures – Cable element test methods
IEC 60794-1-31, Optical fibre cables – Part 1-31: Generic specification – Optical cable
elements – Optical fibre ribbon
IEC 60794-2:20022017, Optical fibre cables – Part 2: Indoor cables – Sectional specification
IEC 60794-3:2001, Optical fibre cables – Part 3: Sectional specification – Outdoor cables
IEC 60811-202, Electric and optical fibre cables – Test methods for non-metallic materials –
Part 202: General tests – Measurement of thickness of non-metallic sheath
IEC 60811-203, Electric and optical fibre cables – Test methods for non-metallic materials –
Part 203: General tests – Measurement of overall dimensions.
IEC 60811-504, Electric and optical fibre cables – Test methods for non-metallic materials –
Part 504: Mechanical tests – Bending tests at low temperature for insulation and sheaths
IEC/TR 62222, Fire performance of communication cables installed in buildings
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 60794-1-1 apply.
ISO and IEC maintain terminology databases for use in standardization at the following
addresses:
• IEC Electropedia: available at https://www.electropedia.org/
• ISO Online browsing platform: available at https://www.iso.org/obp
4 Construction
4.1 General
In addition to the constructional requirements in IEC 60794-2, the following considerations
apply to multi-fibre indoor cables.
The cable shall be designed and manufactured for an expected operating lifetime of at least
15 years. In this context, the attenuation at the operational wavelength(s) of the optical fibres
___________
2 To be published.
– 8 – IEC 60794-2-20:2024 RLV © IEC 2024
contained in the installed cable shall not exceed values agreed between customer and supplier
specified in 5.5. The materials in the cable shall not present a health or environmental hazard
within its intended use.
Optical elements may comprise any of the cable elements described in 4.3 to 4.8 or in
IEC 60794-1-3.
There shall be no fibre splice in a delivery length unless otherwise agreed by customer and
supplier.
It shall be possible to identify each individual fibre throughout the length of the cable.
4.2 Optical fibres
Class A1 multimode fibres which meet the requirements of IEC 60793-2-10 or class B sub-
categories B1.1, B1.3, B6_a, and B6_b single-mode optical fibres which meet the requirements
of IEC 60793-2-50 shall be used. The linear coefficient of optical fibre attenuation and
attenuation point discontinuity may be affected by the cable manufacturing process. Maximum
values for these optical characteristics shall be agreed between customer and supplier.
Multimode or single-mode optical fibres meeting the requirements of IEC 60793-2-10 sub-
categories A1-OM1 to A1-OM5 or IEC 60793-2-50 categories B-652 and B-657 shall be used.
The linear coefficient of optical fibre attenuation and attenuation point discontinuity may be
affected by the cable manufacturing process. Maximum values for these optical characteristics
shall be as specified in 5.5.
4.3 Buffer
If a tight or semi-tight (loosely applied) buffer is required, it shall consist of one or more layers
of inert material. The buffer shall be easily removable. For tight buffers, the buffer and fibre
primary coating shall be removable in one operation over a minimum length of 15 mm to 25 mm,
depending on customer requirements. For semi-tight buffers, the buffer shall be easily
removable over a minimum length of 0,3 m to 2,0 m 300 mm. For loose buffers, the buffer shall
be easily removable over a length of not less than 1,0 m. Buffer dimensions are shown in
Table 1.
Table 1 – Dimensions of buffered fibres
Buffer type Nominal diameter Tolerances
mm mm
Semi-tight or loose buffer 0,3 to 1,4 1,3 ±0,05
Tight buffer 0,3 to 1,0 ±0,05
4.4 Ruggedized fibre
Further protection can be provided to tight or semi-tight buffered fibres by surrounding them
with non-metallic strength members within a sheath of suitable material.
4.5 Slotted core
The slotted core is obtained by extruding a suitable material with a defined number of slots,
providing helical or SZ (reverse-oscillating lay) configuration along the core. One or more
primary coated fibres or optical elements such as ribbons or fibre bundles are located in each
slot.
4.6 Tube
One or more primary coated or buffered fibres or ribbons are packaged (loosely or not) in a
tube construction which may be filled. The tube may be reinforced with a composite wall. The
polymeric tube may be hard, to provide some crush protection to the fibre bundle or soft to
enable easy stripability of the tube without specialized tools.
4.7 Stranded tube
Multiple tubes, containing one or more primary coated or buffered fibres or ribbons, are may
be:
• stranded around a central member,
• non-stranded, or
• homogeneous optical tubes stranded using helical or SZ configurations.
For the sake of preserving cable geometry, some tubes may be "filler" or "empty" elements not
containing optical fibres.
4.8 Ribbon structure
Ribbon structures shall conform to 6.5 and 8.2.3 of IEC 60794-3:2001 IEC 60794-1-31. Fibres
shall be arranged to be parallel and formed into ribbons so that the fibres remain parallel and
do not cross over.
Partially bonded ribbon structures enable the optical fibre ribbon to be rolled up easily and
accommodated very tightly in cables. Unless otherwise specified, each ribbon shall be uniquely
identified with a printed legend or by uniquely colouring the reference fibre and/or by colouring
the matrix material of the ribbon.
4.9 Strength and anti-buckling members
The cable shall be designed with sufficient strength members to meet installation and service
conditions so that the fibres are not subjected to strain in excess of limits agreed between
customer and supplier specified in 5.3.1.
The strength and/or anti-buckling members may be either metallic or non-metallic and may be
located in the cable core and/or under the sheath and/or in the sheath.
4.10 Ripcord
If required, a ripcord may be provided beneath the sheath.
4.11 Sheath
The cable shall have an overall protective sheath. The cable diameter shall be specified in the
relevant blank detail specification (or product) specification.
4.12 Sheath marking
If required, the cable shall be marked as agreed between customer and supplier. The marking
can include identifying marks regarding the manufacturer, fire resistance ratings, jacket length,
date of manufacture, etc.
4.13 Identification
Optical fibres, buffers and sub-unit sheaths shall be easily and uniquely identifiable through the
use of a suitable colour code according to IEC 60304 and/or an easily visible numbering scheme
to be agreed between customer and supplier.

– 10 – IEC 60794-2-20:2024 RLV © IEC 2024
4.14 Examples of cable constructions
Examples of some main types of cable construction are shown in Annex A. Other configurations
(e.g. multi-layer constructions) are not precluded if they meet the mechanical, environmental
and transmission requirements given in this document.
5 Tests
5.1 General
Compliance with relevant detail specification requirements shall be verified by carrying out tests
selected from 5.2 to 5.6. It is not intended that all tests be carried out; the frequency of testing
shall be agreed between customer and supplier.
Unless otherwise specified, all tests shall be carried out at room temperature: (23 ± 5) °C.
Attenuation measurements shall be conducted at the highest specified wavelength.
Some of the following tests can be performed on a short sample length of cable which is still an
integral part of a longer length. Thus it becomes possible to detect permanent changes in
attenuation within the measurement uncertainty of the equipment used (see 4.8.2, Assessment
of uncertainties in IEC 60794-1-20:201X). The wavelength and maximum value of this
attenuation change shall be agreed between customer and supplier.
Unless otherwise specified, all tests shall be carried out at standard atmospheric conditions
according to IEC 60794-1-2. These tests are not intended to define end-of-life performance.
The attenuation of cabled fibres shall be as specified in 5.5.
Measurements of attenuation shall be carried out according to IEC 60793-1-40. Change in
attenuation measurements shall be carried out according to IEC 60793-1-46.
NOTE The optimized wavelength for multimode fibre sub-categories A1-OM3 and A1-OM4 is 850 nm and for
A1-OM5 fibre, the targeted operational wavelength(s) is between 850 nm and 950 nm.
5.2 Dimensions
The fibre dimensions and tolerances shall be checked in accordance with the test method C of
as specified in IEC 60793-1-20 or IEC 60793-1-21. The diameter of the buffer and of the cable,
as well as the thickness of the sheath, shall be measured in accordance with the methods of
IEC 60189-1 IEC 60811-202 and IEC 60811-203.
5.3 Mechanical requirements
5.3.1 Cable Tensile performance
Method: IEC 60794-1-21-E1A and/or E1B [4], method E1
Diameter of chuck drums
and transfer devices:  not smaller than the minimum bending diameter specified
for the cable under load
Velocity of transfer device: either 100 mm/min or 100 N/min
Load and duration: 400 N or 9,8 × the weight mass of 1 km of cable, whichever
is greater,and for a minimum period of 510 min
Length of sample: ≥ 50 m and sufficient to achieve the desired accuracy of
measurement of attenuation change (typically 300 m) and
shall be agreed between customer and supplier

Requirements: for E1A there shall be no change in attenuation after the
test
for E1B allowed fibre strain to be agreed between supplier
and customer
there shall be no change in attenuation after the test; there
shall be no visible damage to the cable elements
Fibre strain above 60 % of the proof test of the all-glass fibre while under test load is not
recommended.
The fibre strain shall be less than 60 % of the proof test level of the fibre.
NOTE For certain applications specifying MICE classification of ISO/IEC 24702 11801-1 and
related standards, different load and duration values may be agreed between customer and
supplier.
For exceptionally high fibre count cables, different load values may be agreed between
customer and supplier.
5.3.2 Cable Crush
Method: IEC 60794-1-21-E3, method E3A
Force during installation: 500 N
Duration during installation: 1 min
Force during operation: 300 N
Duration during operation: 15 min
Length between test locations: 500 mm
Total force applied (short term):  500 N
Duration of application of the force: 1 min
Number of tests:  3
Spacing between test places:  500 mm
Requirements: no change in attenuation during the operational test and
after the installation test; there shall be no visible damage
to the cable elements
NOTE For certain applications specifying MICE classification of ISO/IEC 24702 11801-1 and related standards,
different force values may can be agreed between customer and supplier.
5.3.3 Cable Impact
Method: IEC 60794-1-21-, method E4
Radius of striking surface: 12,5 300 mm
Impact energy: 1,0 J
Number of impacts: at least 3, each separated at least 500 mm
Requirements: no fibre breakage
NOTE For certain applications specifying MICE classification of ISO/IEC 24702 11801-1 and related standards,
impact energy values may can be agreed between customer and supplier.
5.3.4 Cable Bending
Method: IEC 60794-1-21-, method E11A
Mandrel diameter: 20 times cable diameter
Number of turns per helix: 6
Number of cycles: 10
– 12 – IEC 60794-2-20:2024 RLV © IEC 2024
Requirements: no fibre breakage
NOTE For certain applications specifying MICE classification of ISO/IEC 24702 11801-1 and related standards,
different mandrel diameter values may can be agreed between customer and supplier.
5.3.5 Cable Repeated bending
Method: IEC 60794-1-21-, method E6
Bending radius: 20 times cable diameter
Number of cycles: 25
Mass of weights: sufficient to minimize specimen sag or bend – typically 4 kg
Requirements: under visual examination without magnification, there shall
be no damage to the sheath and to the cable elements
5.3.6 Cable Bending under tension
Method: IEC 60794-1-21-E18, method E18A
Bending radius: 20 times cable diameter
Load: 400 N or weight of 1 km of cable, whichever is greater
Requirements: no change in attenuation after the test, and
there shall be no visible damage to the cable elements
5.3.7 Cable Bending at low temperature
Method: IEC 60794-1-21-, method E11A (see IEC 60811-504)
Bending radius: 10 times cable diameter
Test temperature: 0 °C, −10 °C or −15 °C depending on application and
customer requirements
Number of turns per helix: according to IEC 60811-504 4
Number of cycles: 2
Requirements: in addition to the requirements of IEC 60811-504, no visible
damage to cable sheath, and no fibre shall break during the
test
5.3.8 Cable Flexing
Method: IEC 60794-1-21-, method E8
Number of cycles: 100
Pulley diameter: 20 times cable diameter
Mass of weights: 2 kg (minimum)
Requirements: no fibre breakage
NOTE For certain applications specifying MICE classification of ISO/IEC 24702 11801-1 and related standards,
different pulley diameter values may can be agreed between customer and supplier.
5.3.9 Cable Torsion
Method: IEC 60794-1-21-, method E7
Number of cycles: 10
Distance between fixed and 125 times cable diameter but not more than 2,0 m
rotation clamp:
Tension load: 20 N
Requirements: no fibre breakage
NOTE For certain applications specifying MICE classification of ISO/IEC 24702 11801-1 and related standards,
different values for the number of cycles may can be agreed between customer and supplier.

5.3.10 Cable Kink
Method: IEC 60794-1-21-, method E10
Minimum loop diameter: 20 times cable diameter
Requirement: no kink shall occur
5.4 Environmental requirements – Temperature cycling
For indoor multi-fibre cables, −10 °C and +60 °C are the recommended low and high
temperatures. Based on different environment classifications, other operating temperatures
may be agreed upon between customer and supplier. Table 2 gives the operating temperature
limits based on environmental classification.
Table 2 – Sample temperature cycling values
Low temperature High temperature
TA TB
*
0 °C +50 °C
a)
b) –5 °C +50 °C
c) –20 °C +60 °C
d) –40 °C +60 °C
*
Condition a), b) c) or d) shall be selected depending on application and customer
requirements, for example condition c) is appropriate for applications to
ISO/IEC 11801 [10].
Table 2 – Typical values for temperature cycling
Low temperature High temperature Sources of temperature limits
TA2 TB2
Performance categories Environmental classification
°C °C of connectors, components of customer premises
a b
and protective housings cabling
−10 +60 C (recommended) M I C1E
x x x
−25 +70 OP M I C2E
x x x
−40 +70 I M I C3E
x x x
A suitable operating service environment (performance category) or environmental classification should be selected
according to the application. A complete list of operating service environments can be found in IEC 60794-1-1:2023.
a
Included in IEC 61753-1. The abbreviations represent:
C: indoor controlled environment;
OP: outdoor protected environment;
I: industrial environment.
b
Included in ISO/IEC 11801-1. For an introduction to the MICE environmental classification system, use

ISO/IEC TR 29106. The abbreviation MICE represents: mechanical, ingress, climatic, electromagnetic.

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Method: IEC 60794-1-22-, method F1
Period: t = sufficient time such that the cable has reached thermal
stability throughout its entire length at the specified
temperature (e.g. 8 h ≤ t ≤ 24 h) (for additional information,
see IEC 60794-1-22:2017, Table 1 in method F1)
Number of cycles: 2
Length of sample: sufficient to achieve the desired accuracy of measurement
of attenuation
Requirements: the wavelength and maximum increase in attenuation both
at T and T and after returning to thermal stability at
A B
ambient temperature shall be agreed between the customer
and supplier the maximum change in attenuation during the
test shall be specified in the relevant detail specification;
there shall be no change in attenuation after the test.

5.5 Transmission requirements
5.5.1 General
The transmission requirements shall be verified in accordance with one of the sectional
specifications defined in IEC 60793-2-10 or IEC 60793-2-50 and shall be agreed between
customer and supplier. Maximum cabled fibre attenuation shall comply with values stated in the
relevant detail specification this document.
5.5.2 Single-mode optical fibres
See Table 3.
Table 3 – Common single-mode optical fibre requirements
Characteristics IEC 60794-2:2017, Requirements Test methods Remarks
Subclause no.
Uncabled optical fibre 4.2 IEC 60793-2-50

λ < λ
Cabled fibre cut-off
cc
4.2 IEC 60793-1-44
wavelength
operational
Point discontinuities at
4.2 ≤ 0,10 dB IEC 60793-1-40
1 550 nm
5.5.3 Single-mode dispersion unshifted (B-652.B) optical fibre
See Table 4.
Table 4 – Cabled fibre attenuation requirements for B-652.B optical fibre
Characteristics IEC 60794-2:2017, Requirements Test methods Remarks
Subclause no.
According to the
Attenuation coefficient
7.3 Detail IEC 60793-1-40
(cabled fibres)
Specification
at 1 310 nm ≤ 1,0 dB/km
at 1 550 nm ≤ 1,0 dB/km
at 1 625 nm ≤ 1,0 dB/km
5.5.4 Single-mode dispersion unshifted (B-652.D) optical fibre
See Table 5.
Table 5 – Cabled fibre attenuation requirements for B-652.D optical fibre
Characteristics IEC 60794-2:2017, Requirements Test methods Remarks
Subclause no.
According to the
Attenuation coefficient
7.3 Detail IEC 60793-1-40
(cabled fibres)
Specification
at 1 310 nm to 1 625 nm ≤ 1,0 dB/km

at 1 383 nm ≤ 1,0 dB/km
at 1 550 nm ≤ 1,0 dB/km
5.5.5 Single-mode (B-657.A) optical fibre
See Table 6.
Table 6 – Cabled fibre attenuation requirements for B-657.A optical fibre
Characteristics IEC 60794-2:2017, Requirements Test methods Remarks
Subclause no.
According to the
Attenuation coefficient
7.3 Detail IEC 60793-1-40
(cabled fibres)
Specification
at 1 310 nm to 1 625 nm ≤ 1,0 dB/km
at 1 383 nm ≤ 1,0 dB/km
at 1 550 nm ≤ 1,0 dB/km
5.5.6 Single-mode (B-657.B) optical fibre
See Table 7.
Table 7 – Cabled fibre attenuation requirements for B-657.B optical fibre
Characteristics IEC 60794-2:2017, Requirements Test methods Remarks
Subclause no.
According to the
Attenuation coefficient
7.3 Detail IEC 60793-1-40
(cabled fibres)
Specification
At 1 310 nm < 1,0 dB/km
At 1 550 nm < 1,0 dB/km
At 1 625 nm < 1,0 dB/km
5.5.7 Multimode optical fibres
See Table 8.
Table 8 – Common multimode optical fibre requirements
Characteristics IEC 60794-2:2017, Requirements Test methods Remarks
Subclause no.
Uncabled optical fibre 4.2 IEC 60793-2-10
Point discontinuities
4.2 ≤ 0,10 dB IEC 60793-1-40
at 850 nm and 1 300 nm
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5.5.8 Multimode (A1-OM1 to A1-OM5) optical fibres
See Table 9.
Table 9 – Cabled fibre attenuation requirements for A1-OM1 to A1-OM5 optical fibres
Characteristics IEC 60794-2:2017, Requirements Test methods Remarks
Subclause no.
According to the
Attenuation coefficient
Detail
7.3 IEC 60793-1-40
(cabled fibres)
Specification
at 850 nm 3,0 dB/km
at 1 300 nm 1,5 dB/km
5.6 Fire performance
IEC TR 62222 provides guidance and recommendations for the requirements and test methods
to be specified for the fire performance of communication cables when installed in buildings.
The recommendations relate to typical applications and installation practices, and an
assessment of the fire hazards presented. Account is also taken of applicable legislation and
regulation.
The recommendations relate to typical applications and installation practices and also take into
account legislation and regulation applicable to the fire performance of cables that govern the
tests to be performed.
Tests to be performed shall be agreed between the customer and the supplier.
IEC TR 62222 references several IEC fire performance test methods and also other test
methods that can be required by local or national legislation and regulation. The tests to be
applied, and the requirements, shall be agreed between the customer and supplier taking into
account the fire hazard presented by the end use application in which the cable is intended to
be used.
Annex A
(informative)
Examples of cable constructions
Figure A.1 to Figure A.9 Figure A.10 provide examples of cable constructions.

Figure A.1 – Example of cross-section of a 12-fibre cable

Figure A.2 – Example of cross-section of a 36-fibre cable

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