IEC 60794-3:2022

Optical fibre cables - Part 3: Outdoor cables - Sectional specification

IEC 60794-3: 2022 specifies the requirements for optical fibre cables and cable elements which are intended to be used externally in communications networks. Other types of applications requiring similar types of cables can be considered. Requirements for cables to be used in ducts, for directly buried applications, aerial cables and cables for lake and river crossings are included in this document. Also included are cables for specialized use in sewers and in water and gas pipes. For aerial application, this document does not cover all functional aspects of cables installed in the vicinity of overhead power lines. For such applications, additional requirements and test methods can be necessary. Moreover, this document excludes optical ground wires and cables attached to the phase or earth conductors of overhead power lines. For cables for lake and river crossings, this document does not cover methods of cable repair, nor repair capability, nor does it cover cables for use with underwater line amplifiers. This fifth edition cancels and replaces the fourth edition published in 2014. This edition constitutes a technical revision. This edition includes the following significant technical change with respect to the previous edition: the ribbon specification has been removed, because it is covered in IEC 60794-1-31.

Câbles à fibres optiques - Partie 3: Câbles extérieurs - Spécification intermédiaire

L'IEC 60794-3: 2022 spécifie les exigences relatives aux câbles et aux éléments de câble à fibres optiques destinés à être utilisés à l'extérieur dans des réseaux de télécommunication. D'autres types d'applications qui nécessitent des câbles d'une catégorie similaire peuvent être pris en considération. Le présent document comporte des exigences qui concernent les câbles destinés à être installés dans des conduites, les câbles directement enterrés, les câbles aériens et les câbles pour traversées de lacs et de rivières. Il comporte également des câbles destinés à des utilisations spécialisées, dans les égouts et dans les conduites d'eau et de gaz. Pour ce qui est des applications aériennes, le présent document ne couvre pas tous les aspects fonctionnels des câbles installés à proximité de lignes aériennes de transport d'énergie. De telles applications peuvent nécessiter l'adjonction d'exigences et de méthodes d'essai. En outre, le présent document exclut les câbles de garde avec fibres optiques et les câbles liés aux conducteurs de phase ou de terre des lignes aériennes de transport d'énergie. Pour les câbles pour traversées de lacs et de rivières, le présent document ne couvre pas les méthodes de réparation du câble ni de capacité de réparation, et ne couvre pas les câbles utilisés dans les amplificateurs de lignes pour traversées de lacs et de rivières. Cette cinquième édition annule et remplace la quatrième édition parue en 2014. Cette édition constitue une révision technique. Cette édition contient la modification technique majeure suivante par rapport à l'édition précédente: la spécification relative aux rubans a été supprimée car elle est couverte par l'IEC 60794-1-31.

General Information

• Status: Published
• Publication Date: 16-Feb-2022
• ICS: 33.180.10 - Fibres and cables
• Technical Committee: SC 86A - Fibres and cables
• Current Stage: PPUB - Publication issued
• Start Date: 17-Feb-2022
• Completion Date: 11-Mar-2022

Relations

• Revises: IEC 60794-3:2014 - Optical fibre cables - Part 3: Outdoor cables - Sectional specification
• Effective Date: 05-Sep-2023

Overview

IEC 60794-3:2022 - Optical fibre cables: Part 3, Outdoor cables (sectional specification) defines requirements for optical fibre cables and cable elements intended for external communications networks. This fifth edition updates the 2014 version and focuses on outdoor applications including ducts, directly buried installations, aerial routes, lake and river crossings, and specialized deployments in sewers and water/gas pipes. Note: the ribbon specification has been removed from this document (now covered by IEC 60794-1-31).

Keywords: IEC 60794-3:2022, optical fibre cables, outdoor cables, aerial cables, duct installation, directly buried, lake and river crossings, sewers, water and gas pipes.

Key Topics

• Scope and exclusions
  • Requirements for external cable use; excludes optical ground wires and cables attached to overhead power line conductors.
  • Additional requirements may be needed for cables installed near overhead power lines; lake/river crossing rules do not address repair methods or use with underwater amplifiers.
• Optical fibre and cable element requirements
  • Specifications for fibre attenuation, cut-off wavelength, PMD, and fibre colouring.
  • Cable element types addressed: tight-buffered/coated fibres, ruggedized fibres, slotted cores, polymeric tubes, metallic tubes. (Ribbon details relocated to IEC 60794-1-31.)
• Cable construction
  • Lay-up of cable elements, core filling, strength members, moisture barriers, sheath and armouring, sheath marking, and hydrogen considerations.
• Installation, testing and quality
  • Installation and operating conditions, characterization of cable elements, applicable mechanical and environmental tests, and quality assurance provisions are included or cross-referenced.
• Referenced test and material standards
  • Cross-references to IEC 60794-1-x series, IEC 60793 optical fibre test parts, IEC 60811 material tests, and technical reports (e.g., IEC TR 62690 hydrogen effects, IEC TR 62691 installation guidance).

Applications

IEC 60794-3:2022 is essential for:

• Cable manufacturers designing outdoor optical fibre products for ducts, direct burial, aerial, and water crossings.
• Network designers and system integrators specifying cable performance and construction for telecom, broadband, and utility networks.
• Procurement and standards teams creating technical specifications and conformity criteria.
• Test laboratories and quality assurance groups implementing mechanical and environmental tests referenced by the standard.
• Utilities and infrastructure owners planning resilient external fibre deployments in challenging environments (sewers, pipes, waterways).

Related standards

• IEC 60794-1-1 (generic specification - general)
• IEC 60794-1-21 / -1-22 / -1-23 / -1-24 (basic cable test procedures - mechanical/environmental/elements)
• IEC 60794-1-31 (ribbon specification)
• IEC 60793 series (optical fibre measurement methods)
• IEC 60811 series (material test methods)
• IEC TR 62690, IEC TR 62691 (guidance on hydrogen effects and installation)

This sectional specification helps ensure consistent, robust outdoor fibre cable design and testing - supporting reliable communications infrastructure across varied environmental conditions.

Standards Content (Sample)

IEC 60794-3 ®
Edition 5.0 2022-02
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Optical fibre cables –
Part 3: Outdoor cables – Sectional specification

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IEC 60794-3 ®
Edition 5.0 2022-02
REDLINE VERSION
INTERNATIONAL
STANDARD
colour
inside
Optical fibre cables –
Part 3: Outdoor cables – Sectional specification
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 33.180.10 ISBN 978-2-8322-4667-2

– 2 – IEC 60794-3:2022 RLV © IEC 2022
CONTENTS
FOREWORD . 4
INTRODUCTION . 6
1 Scope . 7
2 Normative references . 7
3 Terms, definitions, symbols and abbreviated terms . 8
4 Optical fibre . 9
4.1 General . 9
4.2 Attenuation . 9
4.2.1 Attenuation coefficient . 9
4.2.2 Attenuation uniformity – Attenuation discontinuities . 9
4.3 Cut-off wavelength . 9
4.4 Fibre colouring . 9
4.5 Polarization mode dispersion (PMD) . 9
5 Cable element . 9
5.1 General . 9
5.2 Tight secondary coating or buffer . 10
5.3 Ruggedized fibre . 10
5.4 Slotted core . 10
5.5 Polymeric tube . 10
5.6 Ribbon . 11
5.6.1 General .
5.6.2 Dimensions .
5.6.2 Mechanical requirements .
5.7 Metallic tube . 12
5.7.1 Metallic tube on the optical core . 12
5.7.2 Fibres directly located in a metallic tube . 12
6 Optical fibre cable construction . 13
6.1 General . 13
6.2 Lay-up of the cable elements . 13
6.3 Cable core filling . 13
6.4 Strength member . 14
6.5 Moisture barrier . 14
6.6 Cable sheath and armouring . 14
6.6.1 Inner sheath . 14
6.6.2 Armouring . 14
6.6.3 Outer sheath . 14
6.7 Sheath marking . 15
6.8 Hydrogen gas .
7 Installation and operating conditions . 16
8 Characterization of cable elements . 16
9 Optical fibre cable tests . 17
10 Quality assurance . 18
Bibliography . 19

Table 1 – Maximum dimensions of optical fibre ribbons.

Table 1 – Characteristics of different types of cable elements . 17
Table 2 – Mechanical and environmental applicable tests . 18

– 4 – IEC 60794-3:2022 RLV © IEC 2022

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
OPTICAL FIBRE CABLES –
Part 3: Outdoor cables – Sectional specification

FOREWORD
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rights. 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 60794-3:2014. 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 60794-3 has been prepared by subcommittee 86A: Fibres and cables, of IEC technical
committee 86: Fibre optics. It is an International Standard.
This fifth edition cancels and replaces the fourth edition published in 2014. This edition
constitutes a technical revision.
This edition includes the following significant technical change with respect to the previous
edition: the ribbon specification has been removed, because it is covered in IEC 60794-1-31.
The text of this International Standard is based on the following documents:
Draft Report on voting
86A/2155/FDIS 86A/2184/RVD
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
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/standardsdev/publications.
The language used for the development of this International Standard is English.
A list of all parts in the 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,
• 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 60794-3:2022 RLV © IEC 2022
INTRODUCTION
IEC 60794-1-21, IEC 60794-1-22, IEC 60794-1-23, and IEC 60794-1-24 have been (or will be)
divided into multiple standards which defines one test method each. IEC 60794-1-2:2021 gives
cross references between old standards and new standards.

OPTICAL FIBRE CABLES –
Part 3: Outdoor cables – Sectional specification

1 Scope
This part of IEC 60794 specifies the requirements for optical fibre cables and cable elements
which are intended to be used externally in communications networks. Other types of
applications requiring similar types of cables can be considered.
Requirements for cables to be used in ducts, for directly buried applications, aerial cables and
cables for lake and river crossings are included in this document. Also included are cables for
specialized use in sewers and in water and gas pipes.
For aerial application, this document does not cover all functional aspects of cables installed in
the vicinity of overhead power lines. For such applications, additional requirements and test
methods may can be necessary. Moreover, this document excludes optical ground wires and
cables attached to the phase or earth conductors of overhead power lines.
For cables for lake and river crossings, this document does not cover methods of cable repair,
nor repair capability, nor does it cover cables for use with underwater line amplifiers.
NOTE IEC TR 62839-1 gives rules to built an environmental declaration if needed.
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 60304, Standard colours for insulation for low-frequency cables and wires
IEC 60708, Low-frequency cables with polyolefin insulation and moisture barrier polyolefin
sheath
IEC 60793-1-21, Optical fibres – Part 1-21: Measurement methods and test procedures –
Coating geometry
IEC 60793-1-32, Optical fibres – Part 1-32: Measurement methods and test procedures –
Coating strippability
IEC 60793-1-40, Optical fibres – Part 1-40: Measurement methods and test procedures –
Attenuation measurement methods
IEC 60793-1-44, Optical fibres – Part 1-44: Measurement methods and test procedures –
Cut-off wavelength
IEC 60793-2, Optical fibres – Part 2: Product specifications – General
___________
To be published.
– 8 – IEC 60794-3:2022 RLV © IEC 2022
IEC 60794-1-1, Optical fibre cables – Part 1-1: Generic specification – General
IEC 60794-1-21:2015, Optical fibre cables – Part 1-21: Generic specification – Basic optical
cable test procedures – Mechanical test methods
IEC 60794-1-22, Optical fibre cables – Part 1-22: Generic specification – Basic optical cable
test procedures – Environmental test methods
IEC 60794-1-23, Optical fibre cables – Part 1-23: Generic specification – Basic optical cable
test procedures – Cable elements test methods
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 60811-401, Electric and optical fibre cables – Test methods for non-metallic materials –
Part 401: Miscellaneous tests – Thermal ageing methods – Ageing in an air oven
IEC 60811-406, Electric and optical fibre cables – Test methods for non-metallic materials –
Part 406: Miscellaneous tests – Resistance to stress cracking of polyethylene and
polypropylene compounds
IEC 60811-501, Electric and optical fibre cables – Test methods for non-metallic materials –
Part 501: General Mechanical tests – Tests for determining the mechanical properties of
insulating and sheathing compounds
IEC 60811-604:2012, Electric and optical fibre cables – Test methods for non-metallic materials
– Part 604: Physical tests – Measurement of absence of corrosive components in filling
compounds
IEC 60811-607, Electric and optical fibre cables – Test methods for non-metallic materials –
Part 607: Physical tests – Test for the assessment of carbon black dispersion in polyethylene
and polypropylene
IEC TR 62690, Hydrogen effects in optical fibre cables – Guidelines
IEC TR 62691, Optical fibre cables – Guide to the installation of optical fibre cables
3 Terms, definitions, symbols and abbreviated terms
For the purposes of this document, the terms, definitions, symbols and abbreviated terms given
in IEC 60794-1-1 apply.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
___________
To be published.
4 Optical fibre
4.1 General
Optical fibres shall be used which meet the requirements of IEC 60793-2. The fibre type shall
be agreed between the customer and supplier.
4.2 Attenuation
4.2.1 Attenuation coefficient
The maximum cabled fibre attenuation coefficient shall conform to IEC 60794-1-1. Particular
values may be agreed between the customer and supplier.
The attenuation coefficient shall be measured in accordance with IEC 60793-1-40.
4.2.2 Attenuation uniformity – Attenuation discontinuities
Attenuation uniformity shall conform to IEC 60794-1-1.
4.3 Cut-off wavelength
For single-mode fibre, the cabled fibre cut-off wavelength λ shall be less than the operational
cc
wavelength, when measured in accordance with IEC 60793-1-44, and in conformity with
IEC 60794-1-1.
4.4 Fibre colouring
If the primary coated fibres are coloured for identification, the coloured coating shall be readily
identifiable throughout the lifetime of the cable and shall be a reasonable match to IEC 60304.
4.5 Polarization mode dispersion (PMD)
Cabled single-mode fibre PMD shall conform to IEC 60794-1-1.
5 Cable element
5.1 General
Generally, optical cables comprise several elements or individual constituents, depending on
the cable design which takes into account the cable application, operating environment and
manufacturing processes, as well as the need to protect the fibre during handling and cabling.
The material(s) used for a cable element shall be selected to be compatible with the other
elements in contact with it. An appropriate compatibility test method shall be defined in the
family or detail specification.
When the fibres are in contact with a filling compound, the compatibility of the filling compound
with the fibre coating shall be demonstrated by testing coating stripping force stability after
accelerated ageing in accordance with IEC 60794-1-21, Method E5 IEC 60794-1-23, method
G10A, G10B, or G10C method A, B, and C). Aging condition should be in accordance with
IEC 60794-1-22, method F9 , but alternative ageing conditions and tests may be agreed
between the customer and supplier.
___________
These are intented to be replaced. See Introduction.
This is intented to be replaced. See Introduction.

– 10 – IEC 60794-3:2022 RLV © IEC 2022
Optical elements are cable elements containing optical fibres and are designed to be a primary
functional unit of the cable core. They may comprise any of the cable elements described in 5.2
to 5.7. Optical elements and each fibre within a cable element shall be uniquely identified, for
example by colours, a positional configuration, markings, tapes, threads or as specified in the
detail specification.
Tests may be performed on cable elements either in uncabled form or in a finished cable. Unless
otherwise specified, testing shall be performed on cable elements in a finished cable. This
means that testing shall be performed only on a finished cable if the cable element
manufacturing operation is done by the same manufacturer as the cabling operation. Testing
shall be performed on cable elements only if the cable element is supplied by a third party; this
does not exclude testing of the finished cable.
Different types of optical elements are described in 5.2 to 5.7 and in IEC 60794-1-3.
5.2 Tight secondary coating or buffer
If a tight secondary coating is required, it shall consist of one or more layers of polymeric
material. The coating shall be easily removable for splicing. For tight buffers, the buffer and
fibre primary coating shall be removable in one operation over a length of 10 mm to 25 mm,
depending on customer requirements. The nominal overall diameter of the secondary coating
shall be between 800 µm and 900 µm. The value, which shall be agreed between the customer
and supplier, shall have a tolerance of ±50 µm. The fibre/secondary coating eccentricity shall
not exceed 75 µm, unless otherwise agreed between the customer and supplier.
The colour of the tight secondary coating shall be readily identifiable throughout the life-time of
the cable and shall be a reasonable match to IEC 60304.
5.3 Ruggedized fibre
Further protection can be provided to tight secondary coated fibres by surrounding one or more
with non-metallic strength members within a sheath of suitable material (e.g. for fan-out cables).
5.4 Slotted core
The slotted core is obtained by extruding a suitable material (for example polyethylene or
polypropylene) with a defined number of slots, providing helical or SZ configuration along the
core. One or more primary coated fibres or optical element is located in each slot which may
be filled by compound.
The slotted core usually contains a central element which may be either metallic or non-metallic.
In this case, there shall be adequate adhesion between the central element and the extruded
core in order to obtain the required temperature stability and tensile behaviour for the slotted
core element.
The profile of the slot shall be uniform and shall ensure the optical and mechanical performance
required of the optical cable.
5.5 Polymeric tube
One or more primary coated fibres or other optical elements are packaged (loosely or not) in a
tube construction which may be filled by compound. 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 strippability of the tube without specialized tools.

If required, the suitability of the tube shall be determined by an evaluation of its kink resistance
in accordance with IEC 60794-1-23, method G7 .
If used, the filling compound in the tube shall comply with IEC 60794-1-21:2015, method E15.
The filled tube shall comply with IEC 60794-1-21, Method E14 IEC 60794-1-22, method F16 ,
when tested in tube or cabled form.
5.6 Ribbon
5.6.1 General
Optical fibre ribbons are optical fibres assembled in a composite linear array.
Fibres shall be arranged in parallel and formed into ribbons of typically 4, 6, 8, 12, 24 or 36
fibres each according to user requirements. The fibres within the ribbons shall remain parallel
and not cross over.
The design intent is that adjacent fibres within a ribbon are contiguous and that fibre centre
lines are straight, parallel and coplanar.
Unless otherwise specified, each ribbon shall be uniquely identified with a printed legend or by
uniquely colouring the reference fibre in the ribbon and/or by colouring the matrix material of
the ribbon.
Some parameters shall be measured in the ribbon since the corresponding tests on the primary
coated fibre or finished cable are not sufficient for complete characterization. These parameters
are identified below.
5.6.2 Dimensions
Unless otherwise specified in the detail specification, the maximum dimensions and the
structural geometry of optical fibre ribbons shall be as shown in Table 1.
Table 1 – Maximum dimensions of optical fibre ribbons
Fibre alignment
Width Height Extreme fibres Planarity
a
w h b p
Number of fibres
µm µm µm µm
4 1 220 360 786 50
6 1 648 360 1 310 50
8 2 172 360 1 834 50
12 3 220 360 2 882 75
a a
24 6 500 360
Per 12f unit Per 12f uni
a a
36 9 800 360
Per 12f unit Per 12f unit
a
Per unit values are measured with the ribbon separated into the intended sub-units.

___________
This is intented to be replaced. See Introduction.
This is intented to be replaced. See Introduction.

– 12 – IEC 60794-3:2022 RLV © IEC 2022
More stringent requirements may need to be agreed between the customer and supplier,
depending on the splice or the connector technique employed.
The dimensions and structural geometry can be verified with a type test, described as the visual
measurement method (IEC 60794-1-23, Method G2) to establish and ensure proper control of
the ribbon manufacturing process. Once the process is established, and in order to ensure
functional performance, the width and height of the ribbons may be controlled and verified, for
final inspection purposes, with an aperture gauge (IEC 60794-1-23, Method G3) or a dial gauge
(IEC 60794-1-23, Method G4) or by the visual measurement methods.
5.6.3 Mechanical requirements
5.6.3.1 Separability of individual fibres from a ribbon
If fibre breakout capability is required, the ribbons shall be constructed in such a way that fibres
can be separated from the ribbon construction, into sub-units or individual optical fibres, while
meeting the following criteria:
a) the ribbon shall be tested for the ability to break out individual fibres using the tear
(separability) test shown in IEC 60794-1-23, Method G5, or a method agreed upon between
the customer and supplier;
b) breakout shall be accomplished without specialized tools or apparatus;
c) the fibre breakout procedure shall not be permanently detrimental to the fibre optical and
mechanical performance;
d) any colour coding of fibres shall remain sufficiently intact to enable individual fibres to be
distinguished from each other.
5.6.3.2 Ribbon stripping
The coating of individual fibres as well as the residual ribbon bonding material shall be easily
removable. The method of removal shall be agreed between the customer and supplier or shall
be defined in the detail specification.
5.6.3.3 Torsion
The mechanical and functional integrity of a fibre ribbon can be verified by carrying out the
torsion test shown in IEC 60794-1-23, Method G6.
Optical fibre ribbons are optical fibres assembled in a composite linear array.
Ribbon structure, dimensions, mechanical requirements, and identification are specified in
IEC 60794-1-31.
5.7 Metallic tube
5.7.1 Metallic tube on the optical core
A metallic tube (for example, aluminium tube) may be applied over the optical core (for example,
aluminium spacer or stranded tube).
5.7.2 Fibres directly located in a metallic tube
One or more primary coated and coloured fibres are packaged in a metallic hermetically sealed
tube, which shall be filled, if necessary, with a suitable compound to avoid water penetration.
The inside surface of the tube should be smooth without any defects.

6 Optical fibre cable construction
6.1 General
The intention is that the cable should be designed and manufactured for a predicted operating
lifetime of at least 20 years. In this context, the attenuation of the installed cable at the
operational wavelength(s) shall not exceed values agreed between the customer and supplier.
The tests of this document are intended to assess the performance of cables, as manufactured
and under agreed ageing and performance-limit tests. These tests are not intended to define
end-of-life performance, but may be used as agreed between customer and supplier to predict
such performance. The materials in the cable shall not present a health hazard within its
intended use.
The fibres in the cables are usually of the same type, but some cables may contain multiple
specified fibre types and fibres of the same type may have different origins.
There shall be no fibre splice in a delivery length, unless otherwise agreed by the customer and
supplier.
It shall be possible to identify each individual fibre throughout the length of the cable.
For the particular case of cables for aerial application, to avoid excess fibre strain induced by
the environmental conditions, such as wind loading or ice loading, the cable construction, and
particularly the strength members, shall be selected to limit this strain to the value agreed
between the customer and supplier.
6.2 Lay-up of the cable elements
Optical elements as described in Clause 5 may be laid up as follows:
a) optical element(s) without a stranding lay;
b) a number of homogeneous optical elements using helical or SZ configurations (ribbon
elements may be laid up by stacking two or more elements);
c) a number of different configurations in slotted core such as tight coated, ribbon or tube;
d) a number of different configurations in a tube such as tight coated or ribbon;
e) if required, insulated copper conductors in single, pair or quad construction may be laid up
with the optical elements.
6.3 Cable core filling
If specified, the element(s) and, in addition, the cable core shall contain water blocking material,
such as grease-like filling and/ flooding compounds or dry-block swellable water blocking
materials, to prevent longitudinal water penetration in accordance with IEC 60794-1-22, method
F5 . The material shall be easily removed without the use of substances considered to be
hazardous or dangerous. The grease-like filling compound shall comply with IEC 60794-1-21,
Method E15 IEC 60794-1-23, method G9 . The cable shall pass the compound flow test of
Method E14 of IEC 60794-1-21 IEC 60794-1-22, method F16.
The blocking material used shall be compatible with the other relevant cable elements. Where
a grease-like filling compound is used in cables containing metallic elements, it shall be tested
for the presence of corrosive compounds in accordance with Clause 8 4 of IEC 60811-604:2012.
___________
This is intented to be replaced. See Introduction.
This is intented to be replaced. See Introduction.

– 14 – IEC 60794-3:2022 RLV © IEC 2022
6.4 Strength member
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 the
customer and supplier.
The strength member 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.
If required, the aerial cable shall be equipped with a separate suspension strand. The location
and the type of suspension strand depend on the installation practice and environmental
conditions and shall be determined by agreement between the customer and supplier.
For example, the suspension strand and the cable core may form a "figure 8" construction or
the cable may be fastened to a separate suspension strand by lashing or by other suitable
means.
6.5 Moisture barrier
If specified, a moisture barrier shall be provided either by a continuous metallic sheath or by a
metallic tape applied over the cable core with a longitudinal overlap and bonded to the sheath.
Alternatively, other constructions may be adopted by agreement between the customer and
supplier.
In the case of a continuous metallic sheath, the material and its thickness shall be agreed
between the customer and supplier.
Metallic materials that may be used include, but are not limited to, coated and uncoated
aluminium and steel, copper and copper alloys. These metals may be either flat or corrugated
as designated by the detail specification. Splicing of metallic tapes may be allowed, provided
electrical continuity is ensured in the finished cable.
In the case of an aluminium moisture barrier tape, the thickness of the aluminium tape, the
amount of overlap and the adhesion of the aluminium tape to the sheath shall be in accordance
with IEC 60708. The tape may have a reduced nominal thickness by agreement between the
user and the manufacturer. The effectiveness of the moisture barrier may be proved by an
alternative test with agreement between the customer and supplier.
6.6 Cable sheath and armouring
6.6.1 Inner sheath
A cable inner sheath may be applied by agreement between the customer and supplier. When
required for a specific construction, or for manufacturing purposes, cable cores or sub-units
within the core, or both, may be covered by inner sheaths. Unless otherwise specified, the inner
sheath shall be made of polyethylene.
6.6.2 Armouring
Where additional tensile strength or protection from external damage is required, armouring
shall be provided (for example, corrugated steel tape or steel wire armour).
6.6.3 Outer sheath
6.6.3.1 General
The cable shall have a seamless sheath made of UV-stabilized weather-resistant polyethylene,
containing material. In case of a black sheath, carbon black may be used and, in that case, the

material shall contain 2,0 % minimum well dispersed carbon black in accordance with
IEC 60811-607, unless otherwise agreed between the customer and supplier. UV resistance
can also be achieved through the use of other polymers and UV-stabilized master batches. The
use of these types shall be agreed between the customer and supplier.
The sheath thickness (tested in accordance with IEC 60811-202) and cable overall diameter
(tested in accordance with IEC 60811-203) and its variations shall take into account the
installation conditions and shall be determined by the relevant specification or by agreement
between the customer and supplier.
6.6.3.2 Tensile strength and elongation
In case of a polyethylene sheath, when tested in accordance with IEC 60811-501, the measured
values of tensile strength shall be not less than
a) 10 MPa for low- or linear-low-density polyethylene,
b) 12,0 MPa for medium-density polyethylene, and
c) 16,5 MPa for high-density polyethylene.
The measured values of elongation at break shall be not less than 300 %.
Requirements for other material than PE, such as PP or PA, shall be agreed between customer
and supplier.
6.6.3.3 Elongation at break after ageing
The mechanical characteristics of the sheath shall remain sufficiently constant during normal
use. This is checked by determining the elongation at break according to IEC 60811-501 after
an ageing test at 100 °C ± 2 °C for 10 × 24 h according to IEC 60811-401. The median of the
values of elongation at break shall be not less than 300 %.
6.6.3.4 Resistance to environmental stress cracking
The resistance to environmental stress cracking shall comply with the requirements of
IEC 60811-406. Procedure Method B shall be applied.
6.6.3.5 Outer protection of cables for lake and river crossings
The outer protection may be either a layer of polypropylene roves or an outer sheath of
polyethylene or appropriate materials. The particular outer sheath shall be agreed between the
customer and supplier.
If required, the outermost layer shall have a contrasting colour incorporated to facilitate visibility
of cable movement during installation and maintenance operations.
6.7 Sheath marking
If required, the cable shall be marked by a method agreed between the customer and supplier.
Common methods of marking are embossing, sintering, imprinting, hot foil and surface printing.
The information given in the marking text may include cable length, the number of fibres, fibre
type, manufacturer’s name and the date of manufacture.
The characters shall be spaced at intervals of not more than 1 m. The actual length of the cable
+1
shall be within % of the length indicated by the length marking. For example, 1 000 m of
cable, if the starting sheath length mark was 0, should have a final sheath mark in the range
990 m to 1 000 m. Occasional illegible markings are permitted, provided that a legible mark is

– 16 – IEC 60794-3:2022 RLV © IEC 2022
located within 5 m of the illegible mark. Cables may be remarked in a second contrasting colour,
if the first marking process is unsuccessful.
Marking may be provided as a single or double line of marking. A single line of marking shall
be provided by marking longitudinally along the length of the cable. A double line of marking
shall be provided with the two lines diametrically opposite each other, longitudinally along the
length of the cable.
The abrasion resistance of the sheath markings shall be demonstrated in accordance with
IEC 60794-1-21, method E2B .
For a double line of marking, the abrasion resistance test needs only be carried out on one line
of marking.
6.8 Hydrogen gas
An informative guideline is given in IEC TR 62690.
7 Installation and operating conditions
Installation and operating conditions shall be agreed between the customer and supplier.
Guidance is given in IEC TR 62691.
8 Characterization of cable elements
The following tests , as indicated in Table 2, are intended to characterize the different types of
cable elements.
The tests indicated in Table 1 shall be used to characterize the different types of cable elements.

___________
This is intented to be replaced. See Introduction.

Table 1 – Characteristics of different types of cable elements
a
Characteristics Family requirements in Remarks
Test methods
this document
Dimensions 5.2 IEC 60793-1-21 Secondary coating
Dimensions 5.3, 5.4, 5.6, 5.7 IEC 60811-202 and Tight buffer, tube, slotted
IEC 60811-203 core and ruggedized
elements
Dimensions 5.6 IEC 60794-1-23, Ribbon
methods G2 or G3 or G4
Bend IEC 60794-1-23, Secondary coating, tight
method G1 buffer, tube
Primary or secondary
Strippability 5.2 IEC 60793-1-32
fibre coatings and tight
buffers
Strippability 5.6 As agreed between Ribbon
supplier and
manufacturer
Separability of individual 5.6 IEC 60794-1-23, Ribbon
fibres from ribbon method G5
Kink 5.5 IEC 60794-1-23, Tube
method G7
IEC 60794-1-23,
Torsion 5.6 Ribbon
method G6
Compound flow 5.5 IEC 60794-1-21, method Tube
E14 IEC 60794-1-22,
method F16
a
Some of these methods are under revision. See Introduction.

9 Optical fibre cable tests
Compliance with specification requirements shall be verified by carrying out tests as required
by the relevant family or detail specification. Suitable tests are detailed in Table 2. It is not
intended that all tests shall be carried out; the frequency of testing shall be agreed between the
customer and supplier.
Guidance on qualification sampling and interpretation of test results are given in IEC 60794‑1‑1.
The number of fibres tested shall be representative of the cable design and shall be agreed
between the customer and supplier.
For some tests applicable to "figure 8" constructions, the tests shall be carried out with the
suspension strand. If required by certain installation practices, the "figure 8" cable shall also be
tested without the suspension strand.
Depending on the cable construction and its operational environment, hydrogen induced effects
may be warranted. An informative guideline for hydrogen effects is given in IEC TR 62690.

– 18 – IEC 60794-3:2022 RLV © IEC 2022
Table 2 – Mechanical and environmental applicable tests
a
Characteristics Family requirements Remarks
Test methods
Tensile performance IEC 60794-1-21,
method E1
Sheath abrasion IEC 60794-1-21,
resistance method E2A
Crush IEC 60794-1-21,
method E3
IEC 60794-1-21,
Impact
method E4
Repeated bending IEC 60794-1-21,
method E6
Torsion IEC 60794-1-21,
method E7
Kink IEC 60794-1-21,
method E10
Bend IEC 60794-1-21,
method E11
Shotgun resistance IEC 60794-1-21, Aerial cables with specific
damage method E13 shotgun protection
Bending under tension IEC 60794-1-21,
method E18A
Aeolian vibration IEC 60794-1-21, Longspan aerial cables
method E19
Coiling performance IEC 60794-1-21, Lake and river crossings
method E20
Temperature cycling IEC 60794-1-22,
method F1
IEC 60794-1-22,
Water penetration  Water-blocked cables
method F5B or F5C
Pneumatic resistance IEC 60794-1-22, Unfilled cables protected
method F8 by pressurisation
Ageing IEC 60794-1-22,
method F9
Hydrostatic pressure IEC 60794-1-22, Lake and river crossings
method F10
Ribbon stripping IEC 60794-1-21 Ribbon cables
Method E5B
IEC 60794-1-23,
method G10B
a
The following methods are under revision. See Introduction.

10 Quality assurance
It is the responsibility of the manufacturer to establish quality assurance by quality control
procedures which ensure that the product meets the requirements of this document. When the
customer wishes to specify acceptance tests to other quality procedures, it is essential that an
agreement is reached between the customer and supplier at the time of ordering.

Bibliography
IEC TR 61282-3, Fibre optic communication system design
...

IEC 60794-3 ®
Edition 5.0 2022-02
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Optical fibre cables –
Part 3: Outdoor cables – Sectional specification

Câbles à fibres optiques –
Partie 3: Câbles extérieurs – Spécification intermédiaire

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IEC 60794-3 ®
Edition 5.0 2022-02
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Optical fibre cables –
Part 3: Outdoor cables – Sectional specification

Câbles à fibres optiques –
Partie 3: Câbles extérieurs – Spécification intermédiaire

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 33.180.10 ISBN 978-2-8322-1077-4

– 2 – IEC 60794-3:2022 © IEC 2022
CONTENTS
FOREWORD . 3
INTRODUCTION . 5
1 Scope . 6
2 Normative references . 6
3 Terms, definitions, symbols and abbreviated terms . 7
4 Optical fibre . 7
4.1 General . 7
4.2 Attenuation . 7
4.2.1 Attenuation coefficient . 7
4.2.2 Attenuation uniformity – Attenuation discontinuities . 8
4.3 Cut-off wavelength . 8
4.4 Fibre colouring . 8
4.5 Polarization mode dispersion (PMD) . 8
5 Cable element . 8
5.1 General . 8
5.2 Tight secondary coating or buffer . 9
5.3 Ruggedized fibre . 9
5.4 Slotted core . 9
5.5 Polymeric tube . 9
5.6 Ribbon . 9
5.7 Metallic tube . 10
5.7.1 Metallic tube on the optical core . 10
5.7.2 Fibres directly located in a metallic tube . 10
6 Optical fibre cable construction . 10
6.1 General . 10
6.2 Lay-up of the cable elements . 10
6.3 Cable core filling . 11
6.4 Strength member . 11
6.5 Moisture barrier . 11
6.6 Cable sheath and armouring . 12
6.6.1 Inner sheath . 12
6.6.2 Armouring . 12
6.6.3 Outer sheath . 12
6.7 Sheath marking . 13
7 Installation and operating conditions . 13
8 Characterization of cable elements . 13
9 Optical fibre cable tests . 14
10 Quality assurance . 15
Bibliography . 16

Table 1 – Characteristics of different types of cable elements . 14
Table 2 – Mechanical and environmental applicable tests . 15

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
OPTICAL FIBRE CABLES –
Part 3: Outdoor cables – Sectional specification

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-governmental organizations liaising
with the IEC also participate in this preparation. IEC collaborates closely 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
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
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.
IEC 60794-3 has been prepared by subcommittee 86A: Fibres and cables, of IEC technical
committee 86: Fibre optics. It is an International Standard.
This fifth edition cancels and replaces the fourth edition published in 2014. This edition
constitutes a technical revision.
This edition includes the following significant technical change with respect to the previous
edition: the ribbon specification has been removed, because it is covered in IEC 60794-1-31.
The text of this International Standard is based on the following documents:
Draft Report on voting
86A/2155/FDIS 86A/2184/RVD
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
– 4 – IEC 60794-3:2022 © IEC 2022
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/standardsdev/publications.
The language used for the development of this International Standard is English.
A list of all parts in the 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,
• replaced by a revised edition, or
• amended.
INTRODUCTION
IEC 60794-1-21, IEC 60794-1-22, IEC 60794-1-23, and IEC 60794-1-24 have been (or will be)
divided into multiple standards which defines one test method each. IEC 60794-1-2:2021 gives
cross references between old standards and new standards.

– 6 – IEC 60794-3:2022 © IEC 2022
OPTICAL FIBRE CABLES –
Part 3: Outdoor cables – Sectional specification

1 Scope
This part of IEC 60794 specifies the requirements for optical fibre cables and cable elements
which are intended to be used externally in communications networks. Other types of
applications requiring similar types of cables can be considered.
Requirements for cables to be used in ducts, for directly buried applications, aerial cables and
cables for lake and river crossings are included in this document. Also included are cables for
specialized use in sewers and in water and gas pipes.
For aerial application, this document does not cover all functional aspects of cables installed in
the vicinity of overhead power lines. For such applications, additional requirements and test
methods can be necessary. Moreover, this document excludes optical ground wires and cables
attached to the phase or earth conductors of overhead power lines.
For cables for lake and river crossings, this document does not cover methods of cable repair,
nor repair capability, nor does it cover cables for use with underwater line amplifiers.
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 60304, Standard colours for insulation for low-frequency cables and wires
IEC 60708, Low-frequency cables with polyolefin insulation and moisture barrier polyolefin
sheath
IEC 60793-1-21, Optical fibres – Part 1-21: Measurement methods and test procedures –
Coating geometry
IEC 60793-1-32, Optical fibres – Part 1-32: Measurement methods and test procedures –
Coating strippability
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 60793-2, Optical fibres – Part 2: Product specifications – General
IEC 60794-1-1, Optical fibre cables – Part 1-1: Generic specification – General
IEC 60794-1-21:2015, Optical fibre cables – Part 1-21: Generic specification – Basic optical
cable test procedures – Mechanical test methods

IEC 60794-1-22, Optical fibre cables – Part 1-22: Generic specification – Basic optical cable
test procedures – Environmental test methods
IEC 60794-1-23, Optical fibre cables – Part 1-23: Generic specification – Basic optical cable
test procedures – Cable elements test methods
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 60811-401, Electric and optical fibre cables – Test methods for non-metallic materials –
Part 401: Miscellaneous tests – Thermal ageing methods – Ageing in an air oven
IEC 60811-406, Electric and optical fibre cables – Test methods for non-metallic materials –
Part 406: Miscellaneous tests – Resistance to stress cracking of polyethylene and
polypropylene compounds
IEC 60811-501, Electric and optical fibre cables – Test methods for non-metallic materials –
Part 501: Mechanical tests – Tests for determining the mechanical properties of insulating and
sheathing compounds
IEC 60811-604:2012, Electric and optical fibre cables – Test methods for non-metallic materials
– Part 604: Physical tests – Measurement of absence of corrosive components in filling
compounds
IEC 60811-607, Electric and optical fibre cables – Test methods for non-metallic materials –
Part 607: Physical tests – Test for the assessment of carbon black dispersion in polyethylene
and polypropylene
3 Terms, definitions, symbols and abbreviated terms
For the purposes of this document, the terms, definitions, symbols and abbreviated terms given
in IEC 60794-1-1 apply.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
4 Optical fibre
4.1 General
Optical fibres shall be used which meet the requirements of IEC 60793-2. The fibre type shall
be agreed between the customer and supplier.
4.2 Attenuation
4.2.1 Attenuation coefficient
The maximum cabled fibre attenuation coefficient shall conform to IEC 60794-1-1. Particular
values may be agreed between the customer and supplier.

– 8 – IEC 60794-3:2022 © IEC 2022
The attenuation coefficient shall be measured in accordance with IEC 60793-1-40.
4.2.2 Attenuation uniformity – Attenuation discontinuities
Attenuation uniformity shall conform to IEC 60794-1-1.
4.3 Cut-off wavelength
For single-mode fibre, the cabled fibre cut-off wavelength λ shall be less than the operational
cc
wavelength, when measured in accordance with IEC 60793-1-44, and in conformity with
IEC 60794-1-1.
4.4 Fibre colouring
If the primary coated fibres are coloured for identification, the coloured coating shall be readily
identifiable throughout the lifetime of the cable and shall be a reasonable match to IEC 60304.
4.5 Polarization mode dispersion (PMD)
Cabled single-mode fibre PMD shall conform to IEC 60794-1-1.
5 Cable element
5.1 General
Generally, optical cables comprise several elements or individual constituents, depending on
the cable design which takes into account the cable application, operating environment and
manufacturing processes, as well as the need to protect the fibre during handling and cabling.
The material(s) used for a cable element shall be selected to be compatible with the other
elements in contact with it. An appropriate compatibility test method shall be defined in the
family or detail specification.
When the fibres are in contact with a filling compound, the compatibility of the filling compound
with the fibre coating shall be demonstrated by testing coating stripping force stability after
accelerated ageing in accordance with IEC 60794-1-23, method G10A, G10B, or G10C method
A, B, and C). Aging condition should be in accordance with IEC 60794-1-22, method F9 , but
alternative ageing conditions and tests may be agreed between the customer and supplier.
Optical elements are cable elements containing optical fibres and are designed to be a primary
functional unit of the cable core. They may comprise any of the cable elements described in 5.2
to 5.7. Optical elements and each fibre within a cable element shall be uniquely identified, for
example by colours, a positional configuration, markings, tapes, threads or as specified in the
detail specification.
Tests may be performed on cable elements either in uncabled form or in a finished cable. Unless
otherwise specified, testing shall be performed on cable elements in a finished cable. This
means that testing shall be performed only on a finished cable if the cable element
manufacturing operation is done by the same manufacturer as the cabling operation. Testing
shall be performed on cable elements only if the cable element is supplied by a third party; this
does not exclude testing of the finished cable.
Different types of optical elements are described in 5.2 to 5.7 and in IEC 60794-1-3.
___________
These are intented to be replaced. See Introduction.
This is intented to be replaced. See Introduction.

5.2 Tight secondary coating or buffer
If a tight secondary coating is required, it shall consist of one or more layers of polymeric
material. The coating shall be easily removable for splicing. For tight buffers, the buffer and
fibre primary coating shall be removable in one operation over a length of 10 mm to 25 mm,
depending on customer requirements. The nominal overall diameter of the secondary coating
shall be between 800 µm and 900 µm. The value, which shall be agreed between the customer
and supplier, shall have a tolerance of ±50 µm. The fibre/secondary coating eccentricity shall
not exceed 75 µm, unless otherwise agreed between the customer and supplier.
The colour of the tight secondary coating shall be readily identifiable throughout the life-time of
the cable and shall be a reasonable match to IEC 60304.
5.3 Ruggedized fibre
Further protection can be provided to tight secondary coated fibres by surrounding one or more
with non-metallic strength members within a sheath of suitable material (e.g. for fan-out cables).
5.4 Slotted core
The slotted core is obtained by extruding a suitable material (for example polyethylene or
polypropylene) with a defined number of slots, providing helical or SZ configuration along the
core. One or more primary coated fibres or optical element is located in each slot which may
be filled by compound.
The slotted core usually contains a central element which may be either metallic or non-metallic.
In this case, there shall be adequate adhesion between the central element and the extruded
core in order to obtain the required temperature stability and tensile behaviour for the slotted
core element.
The profile of the slot shall be uniform and shall ensure the optical and mechanical performance
required of the optical cable.
5.5 Polymeric tube
One or more primary coated fibres or other optical elements are packaged (loosely or not) in a
tube construction which may be filled by compound. 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 strippability of the tube without specialized tools.
If required, the suitability of the tube shall be determined by an evaluation of its kink resistance
in accordance with IEC 60794-1-23, method G7 .
If used, the filling compound in the tube shall comply with IEC 60794-1-21:2015, method E15.
The filled tube shall comply with IEC 60794-1-22, method F16 , when tested in tube or cabled
form.
5.6 Ribbon
Optical fibre ribbons are optical fibres assembled in a composite linear array.
Ribbon structure, dimensions, mechanical requirements, and identification are specified in
IEC 60794-1-31.
___________
This is intented to be replaced. See Introduction.
This is intented to be replaced. See Introduction.

– 10 – IEC 60794-3:2022 © IEC 2022
5.7 Metallic tube
5.7.1 Metallic tube on the optical core
A metallic tube (for example, aluminium tube) may be applied over the optical core (for example,
aluminium spacer or stranded tube).
5.7.2 Fibres directly located in a metallic tube
One or more primary coated and coloured fibres are packaged in a metallic hermetically sealed
tube, which shall be filled, if necessary, with a suitable compound to avoid water penetration.
The inside surface of the tube should be smooth without any defects.
6 Optical fibre cable construction
6.1 General
The intention is that the cable should be designed and manufactured for a predicted operating
lifetime of at least 20 years. In this context, the attenuation of the installed cable at the
operational wavelength(s) shall not exceed values agreed between the customer and supplier.
The tests of this document are intended to assess the performance of cables, as manufactured
and under agreed ageing and performance-limit tests. These tests are not intended to define
end-of-life performance, but may be used as agreed between customer and supplier to predict
such performance. The materials in the cable shall not present a health hazard within its
intended use.
The fibres in the cables are usually of the same type, but some cables may contain multiple
specified fibre types and fibres of the same type may have different origins.
There shall be no fibre splice in a delivery length, unless otherwise agreed by the customer and
supplier.
It shall be possible to identify each individual fibre throughout the length of the cable.
For the particular case of cables for aerial application, to avoid excess fibre strain induced by
the environmental conditions, such as wind loading or ice loading, the cable construction, and
particularly the strength members, shall be selected to limit this strain to the value agreed
between the customer and supplier.
6.2 Lay-up of the cable elements
Optical elements as described in Clause 5 may be laid up as follows:
a) optical element(s) without a stranding lay;
b) a number of homogeneous optical elements using helical or SZ configurations (ribbon
elements may be laid up by stacking two or more elements);
c) a number of different configurations in slotted core such as tight coated, ribbon or tube;
d) a number of different configurations in a tube such as tight coated or ribbon;
e) if required, insulated copper conductors in single, pair or quad construction may be laid up
with the optical elements.
6.3 Cable core filling
If specified, the element(s) and, in addition, the cable core shall contain water blocking material,
such as filling and flooding compounds or dry swellable water blocking materials, to prevent
. The material
longitudinal water penetration in accordance with IEC 60794-1-22, method F5
shall be easily removed without the use of substances considered to be hazardous or dangerous.
The filling compound shall comply with IEC 60794-1-23, method G9 . The cable shall pass the
compound flow test of IEC 60794-1-22, method F16.
The blocking material used shall be compatible with the other relevant cable elements. Where
a grease-like filling compound is used in cables containing metallic elements, it shall be tested
for the presence of corrosive compounds in accordance with Clause 4 of IEC 60811-604:2012.
6.4 Strength member
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 the
customer and supplier.
The strength member 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.
If required, the aerial cable shall be equipped with a separate suspension strand. The location
and the type of suspension strand depend on the installation practice and environmental
conditions and shall be determined by agreement between the customer and supplier.
For example, the suspension strand and the cable core may form a "figure 8" construction or
the cable may be fastened to a separate suspension strand by lashing or by other suitable
means.
6.5 Moisture barrier
If specified, a moisture barrier shall be provided either by a continuous metallic sheath or by a
metallic tape applied over the cable core with a longitudinal overlap and bonded to the sheath.
Alternatively, other constructions may be adopted by agreement between the customer and
supplier.
In the case of a continuous metallic sheath, the material and its thickness shall be agreed
between the customer and supplier.
Metallic materials that may be used include, but are not limited to, coated and uncoated
aluminium and steel, copper and copper alloys. These metals may be either flat or corrugated
as designated by the detail specification. Splicing of metallic tapes may be allowed, provided
electrical continuity is ensured in the finished cable.
In the case of an aluminium moisture barrier tape, the thickness of the aluminium tape, the
amount of overlap and the adhesion of the aluminium tape to the sheath shall be in accordance
with IEC 60708. The tape may have a reduced nominal thickness by agreement between the
user and the manufacturer. The effectiveness of the moisture barrier may be proved by an
alternative test with agreement between the customer and supplier.
___________
This is intented to be replaced. See Introduction.
This is intented to be replaced. See Introduction.

– 12 – IEC 60794-3:2022 © IEC 2022
6.6 Cable sheath and armouring
6.6.1 Inner sheath
A cable inner sheath may be applied by agreement between the customer and supplier. When
required for a specific construction, or for manufacturing purposes, cable cores or sub-units
within the core, or both, may be covered by inner sheaths. Unless otherwise specified, the inner
sheath shall be made of polyethylene.
6.6.2 Armouring
Where additional tensile strength or protection from external damage is required, armouring
shall be provided (for example, corrugated steel tape or steel wire armour).
6.6.3 Outer sheath
6.6.3.1 General
The cable shall have a seamless sheath made of UV-stabilized weather-resistant material. In
case of a black sheath, carbon black may be used and, in that case, the material shall contain
2,0 % minimum well dispersed carbon black in accordance with IEC 60811-607, unless
otherwise agreed between the customer and supplier. UV resistance can also be achieved
through the use of other polymers and UV-stabilized master batches. The use of these types
shall be agreed between the customer and supplier.
The sheath thickness (tested in accordance with IEC 60811-202) and cable overall diameter
(tested in accordance with IEC 60811-203) and its variations shall take into account the
installation conditions and shall be determined by the relevant specification or by agreement
between the customer and supplier.
6.6.3.2 Tensile strength and elongation
In case of a polyethylene sheath, when tested in accordance with IEC 60811-501, the measured
values of tensile strength shall be not less than
a) 10 MPa for low- or linear-low-density polyethylene,
b) 12,0 MPa for medium-density polyethylene, and
c) 16,5 MPa for high-density polyethylene.
The measured values of elongation at break shall be not less than 300 %.
Requirements for other material than PE, such as PP or PA, shall be agreed between customer
and supplier.
6.6.3.3 Elongation at break after ageing
The mechanical characteristics of the sheath shall remain sufficiently constant during normal
use. This is checked by determining the elongation at break according to IEC 60811-501 after
an ageing test at 100 °C ± 2 °C for 10 × 24 h according to IEC 60811-401. The median of the
values of elongation at break shall be not less than 300 %.
6.6.3.4 Resistance to environmental stress cracking
The resistance to environmental stress cracking shall comply with the requirements of
IEC 60811-406. Method B shall be applied.

6.6.3.5 Outer protection of cables for lake and river crossings
The outer protection may be either a layer of polypropylene roves or an outer sheath of
polyethylene or appropriate materials. The particular outer sheath shall be agreed between the
customer and supplier.
If required, the outermost layer shall have a contrasting colour incorporated to facilitate visibility
of cable movement during installation and maintenance operations.
6.7 Sheath marking
If required, the cable shall be marked by a method agreed between the customer and supplier.
Common methods of marking are embossing, sintering, imprinting, hot foil and surface printing.
The information given in the marking text may include cable length, the number of fibres, fibre
type, manufacturer’s name and the date of manufacture.
The characters shall be spaced at intervals of not more than 1 m. The actual length of the cable
+1
shall be within % of the length indicated by the length marking. For example, 1 000 m of
cable, if the starting sheath length mark was 0, should have a final sheath mark in the range
990 m to 1 000 m. Occasional illegible markings are permitted, provided that a legible mark is
located within 5 m of the illegible mark. Cables may be remarked in a second contrasting colour,
if the first marking process is unsuccessful.
Marking may be provided as a single or double line of marking. A single line of marking shall
be provided by marking longitudinally along the length of the cable. A double line of marking
shall be provided with the two lines diametrically opposite each other, longitudinally along the
length of the cable.
The abrasion resistance of the sheath markings shall be demonstrated in accordance with
IEC 60794-1-21, method E2B .
For a double line of marking, the abrasion resistance test needs only be carried out on one line
of marking.
7 Installation and operating conditions
Installation and operating conditions shall be agreed between the customer and supplier.
Guidance is given in IEC TR 62691.
8 Characterization of cable elements
The tests indicated in Table 1 shall be used to characterize the different types of cable elements.
___________
This is intented to be replaced. See Introduction.

– 14 – IEC 60794-3:2022 © IEC 2022
Table 1 – Characteristics of different types of cable elements
a
Characteristics Family requirements in Remarks
Test methods
this document
Dimensions 5.2 IEC 60793-1-21 Secondary coating
Dimensions 5.3, 5.4, 5.6, 5.7 IEC 60811-202 and Tight buffer, tube, slotted
IEC 60811-203 core and ruggedized
elements
Dimensions 5.6 IEC 60794-1-23, Ribbon
methods G2 or G3
Bend IEC 60794-1-23, Secondary coating, tight
method G1 buffer, tube
Primary or secondary
Strippability 5.2 IEC 60793-1-32
fibre coatings and tight
buffers
Strippability 5.6 As agreed between Ribbon
supplier and
manufacturer
Separability of individual 5.6 IEC 60794-1-23, Ribbon
fibres from ribbon method G5
Kink 5.5 IEC 60794-1-23, Tube
method G7
IEC 60794-1-23,
Torsion 5.6 Ribbon
method G6
Compound flow 5.5 IEC 60794-1-22, Tube
method F16
a
Some of these methods are under revision. See Introduction.

9 Optical fibre cable tests
Compliance with specification requirements shall be verified by carrying out tests as required
by the relevant family or detail specification. Suitable tests are detailed in Table 2. It is not
intended that all tests shall be carried out; the frequency of testing shall be agreed between the
customer and supplier.
Guidance on qualification sampling and interpretation of test results are given in IEC 60794‑1‑1.
The number of fibres tested shall be representative of the cable design and shall be agreed
between the customer and supplier.
For some tests applicable to "figure 8" constructions, the tests shall be carried out with the
suspension strand. If required by certain installation practices, the "figure 8" cable shall also be
tested without the suspension strand.
Depending on the cable construction and its operational environment, hydrogen induced effects
may be warranted. An informative guideline for hydrogen effects is given in IEC TR 62690.

Table 2 – Mechanical and environmental applicable tests
a
Characteristics Family requirements Remarks
Test methods
Tensile performance IEC 60794-1-21,
method E1
Sheath abrasion IEC 60794-1-21,
resistance method E2A
Crush IEC 60794-1-21,
method E3
IEC 60794-1-21,
Impact
method E4
Repeated bending IEC 60794-1-21,
method E6
Torsion IEC 60794-1-21,
method E7
Kink IEC 60794-1-21,
method E10
Bend IEC 60794-1-21,
method E11
Shotgun damage IEC 60794-1-21, Aerial cables with specific
method E13 shotgun protection
Bending under tension IEC 60794-1-21,
method E18A
Aeolian vibration IEC 60794-1-21, Longspan aerial cables
method E19
Coiling performance IEC 60794-1-21, Lake and river crossings
method E20
Temperature cycling IEC 60794-1-22,
method F1
IEC 60794-1-22,
Water penetration  Water-blocked cables
method F5B or F5C
Pneumatic resistance IEC 60794-1-22, Unfilled cables protected
method F8 by pressurisation
Ageing IEC 60794-1-22,
method F9
Hydrostatic pressure IEC 60794-1-22, Lake and river crossings
method F10
Ribbon stripping IEC 60794-1-23, Ribbon cables
method G10B
a
The following methods are under revision. See Introduction.

10 Quality assurance
It is the responsibility of the manufacturer to establish quality assurance by quality control
procedures which ensure that the product meets the requirements of this document. When the
customer wishes to specify acceptance tests to other quality procedures, it is essential that an
agreement is reached between the customer and supplier at the time of ordering.

– 16 – IEC 60794-3:2022 © IEC 2022
Bibliography
IEC 60794-1-2:2021, Optical fibre cables – Part 1-2: General specification – Basic optical test
procedures – General guidance
IEC 60794-1-24, Optical fibre cables – Part 1-24: Generic specification – Basic optical cable
test procedures – Electrical test methods
IEC 60794-1-3, Optical fibre cables – Part 1-3: Generic specification – Optical cable elements
IEC 60794-1-31, Optical fibre cables – Part 1-31: Generic specification – Optical cable elements
– Optical fibre ribbon
IEC TR 62690, Hydrogen effects in optical fibre cables – Guidelines
IEC TR 62691, Optical fibre cables – Guidelines to the installation of optical fibre cables
IEC TR 62839-1, Environmental declaration – Part 1: Wires, cables and accessory products –
Specific rules
IEC TR 62959, Optical fibre cables – Shrinkage effects on cable and cable element end
termination – Guidance
IEC TR 63194, Guidance on colour coding of optical fibre cables

___________
___________
This publication has been withdrawn.

– 18 – IEC 60794-3:2022 © IEC 2022
SOMMAIRE
AVANT-PROPOS . 19
INTRODUCTION . 21
1 Domaine d'application . 22
2 Références normatives . 22
3 Termes, définitions, symboles et termes abrégés . 23
4 Fibres optiques . 23
4.1 Généralités . 23
4.2 Affaiblissement . 24
4.2.1 Affaiblissement linéique . 24
4.2.2 Uniformité d'affaiblissement – Discontinuité d'affaiblissement . 24
4.3 Longueur d'onde de coupure . 24
4.4 Coloration des fibres . 24
4.5 Dispersion de mode de polarisation (PMD - polarization mode dispersion) . 24
5 Élément de câble . 24
5.1 Généralités . 24
5.2 Revêtement secondaire serré ou revêtement protecteur .
...