IEC 60794-3:2014

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

IEC 60794-3:2014 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 standard. Also included are cables for specialized use in sewers and in water and gas pipes. For aerial application, this standard 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 be necessary. Moreover, this standard 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 standard does not cover methods of cable repair, nor repair capability, nor does it cover cables for use with underwater line amplifiers. This fourth edition cancels and replaces the third edition, published in 2001, and constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition:
- the specification has been streamlined by cross-referencing with IEC 60794-1-1;
- soft strippable tubes introduced into the "polymeric" tube heading and metal tubes have been added;
- ribbon clauses have been simplified;
- more precise outer sheath details have been added;
- cable element tests and cable tests have been simplified by the use of tables instead of text;
- Annex A on PMD has been removed, to avoid duplication with IEC TR 61282-3. Keywords: outdoor cables, requirements for optical fibre cables and cable elements

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

L'IEC 60794-3:2014 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 nécessitant des câbles d'un type similaire peuvent être envisagés. La présente norme comporte des exigences concernant 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. Elle 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, la présente norme 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, la présente norme 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, la présente norme 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 quatrième édition annule et remplace la troisième édition, parue en 2001, dont elle constitue une révision technique. Cette édition contient les modifications techniques majeures suivantes par rapport à l'édition précédente:
- la spécification a été simplifiée en introduisant des références croisées avec l'IEC 60794-1-1;
- des tubes souples dénudables introduits en tête de tubes polymères et des tubes métalliques ont été ajoutés;
- les articles relatifs aux rubans ont été simplifiés;
- des informations plus précises sur les gaines extérieures ont été ajoutées;
- les essais sur les éléments de câble et les essais sur les câbles ont été simplifiés en remplaçant le texte par des tableaux;
- l'Annexe A sur la PMD a été retirée pour éviter une redondance avec l'IEC TR 61282-3. Mots clés: câbles extérieurs, exigences relatives aux câbles et aux éléments de câble à fibres optiques

General Information

• Status: Published
• Publication Date: 08-Sep-2014
• ICS: 33.180.10 - Fibres and cables
• Technical Committee: SC 86A - Fibres and cables
• Current Stage: DELPUB - Deleted Publication
• Start Date: 17-Feb-2022
• Completion Date: 28-Aug-2020

Relations

• Revised: IEC 60794-3:2022 - Optical fibre cables - Part 3: Outdoor cables - Sectional specification
• Effective Date: 05-Sep-2023
• Revises: IEC 60794-3:2001 - Optical fibre cables - Part 3: Sectional specification - Outdoor cables
• Effective Date: 05-Sep-2023

IEC 60794-3:2014 – Optical Fibre Cables: Outdoor Cables Specification

Overview

IEC 60794-3:2014 is an international standard published by the International Electrotechnical Commission (IEC) that defines the technical requirements for optical fibre cables and cable elements intended for outdoor use. The fourth edition of this standard provides updated and streamlined specifications for a wide range of outdoor optical cables used in telecommunications networks. It covers various environments, including ducts, direct burial, aerial installations, and underwater crossings such as lakes and rivers. Specialized applications like sewer deployments and cables within water and gas pipes are also addressed.

Key highlights include precise construction requirements, performance specifications, and environmental considerations tailored for durable and reliable outdoor optical fibre cables. This standard excludes optical ground wires and cables attached to overhead power line conductors, and because of their unique conditions, additional standards may apply to aerial cables near power lines.

Key Topics Covered

• Cable Elements and Construction: Detailed requirements for cable elements such as tight buffers, ruggedized fibres, polymeric and metallic tubes, and fibre ribbons. New to this edition are soft strippable tubes and additional metal tube specifications.
• Cable Types: Specifications for cables suitable for:
  • Duct installation
  • Direct burial applications
  • Aerial cables
  • Lake and river crossings
  • Specialized environments like sewers, water, and gas pipes
• Mechanical and Environmental Performance: Simplified testing procedures using tables instead of long textual descriptions. Mechanical strength, moisture resistance, and environmental endurance are specified to ensure reliability in harsh outdoor conditions.
• Sheath and Armouring: Requirements on cable sheath materials, markings, armouring layers, and moisture barriers designed to protect fibres from external physical and chemical hazards.
• Installation and Operational Conditions: Guidelines defining safe handling, installation practices, and expected operational environmental conditions.
• Streamlining and Simplification: The standard has been revised with cross-references to IEC 60794-1-1, simplified ribbon cable provisions, and clearer outer sheath construction details.

Practical Applications

IEC 60794-3:2014 is essential for manufacturers, network designers, and installers involved in outdoor optical fibre networks:

• Telecommunications Network Deployments: Ensures cables meet durability and performance standards for reliable signal transmission in outdoor infrastructure.
• Aerial and Buried Cable Installations: Specifies constructions optimized for exposure to weather, soil, and mechanical stress.
• Water Crossing Solutions: Provides guidelines for cable design in underwater environments such as lakes and river crossings, though specialized repair methods are outside its scope.
• Industrial and Utility Uses: Addresses use-cases in industrial sewers, water supply pipes, and gas lines, where rugged cable performance is critical.
• Standard Compliance and Quality Assurance: Specifies test methods and quality assurance processes for consistent product performance and international interoperability.

Related Standards

• IEC 60794-1-1 – Generic specification for optical fibre cables, referenced for common requirements.
• IEC 60793 series – Specifications for optical fibres, including measurement methods and performance testing.
• IEC TR 61282-3 – Technical report covering polarization mode dispersion (PMD), referenced to avoid duplication.
• IEC 60304 – Standard colours for cable insulation, relevant for cable element identification.
• IEC 60708 – Low-frequency cables with moisture barrier sheaths, applicable for cable sheath requirements.

---

Keywords: outdoor cables, optical fibre cables, fibre optic cable standards, direct burial optical cables, aerial optical fibre cable, underwater fibre optic cable, IEC 60794-3, optical cable construction, cable sheath requirements, outdoor fibre optic network, telecommunications infrastructure standards.

Standards Content (Sample)

IEC 60794-3 ®
Edition 4.0 2014-09
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
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 4.0 2014-09
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Optical fibre cables –
Part 3: Outdoor cables – Sectional specification

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

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CODE PRIX Q
ICS 33.180.10 ISBN 978-2-8322-1854-9

– 2 – IEC 60794-3:2014 © IEC 2014
CONTENTS
FOREWORD . 4
1 Scope . 6
2 Normative references . 6
3 Terms, definitions, symbols and abbreviations . 7
4 Optical fibre . 7
4.1 General . 7
4.2 Attenuation . 8
4.2.1 Attenuation coefficient . 8
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
5.6.1 General . 9
5.6.2 Dimensions . 10
5.6.3 Mechanical requirements . 10
5.7 Metallic tube . 11
5.7.1 Metallic tube on the optical core . 11
5.7.2 Fibres directly located in a metallic tube . 11
6 Optical fibre cable construction . 11
6.1 General . 11
6.2 Lay-up of the cable elements . 12
6.3 Cable core filling . 12
6.4 Strength member . 12
6.5 Moisture barrier . 12
6.6 Cable sheath and armouring . 13
6.6.1 Inner sheath . 13
6.6.2 Armouring . 13
6.6.3 Outer sheath . 13
6.7 Sheath marking . 14
6.8 Hydrogen gas . 14
7 Installation and operating conditions . 14
8 Characterization of cable elements . 14
9 Optical fibre cable tests . 15
10 Quality assurance . 16
Bibliography . 17

Table 1 – Maximum dimensions of optical fibre ribbons. 10
Table 2 – Characteristics of different types of cable elements . 15
Table 3 – Mechanical and environmental applicable tests . 16

– 4 – IEC 60794-3:2014 © IEC 2014
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
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2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
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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) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 60794-3 has been prepared by subcommittee 86A: Fibres and
cables, of IEC technical committee 86: Fibre optics.
This fourth edition cancels and replaces the third edition, published in 2001, and constitutes a
technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
• the specification has been streamlined by cross-referencing with IEC 60794-1-1;
• soft strippable tubes introduced into the “polymeric” tube heading and metal tubes have
been added;
• ribbon clauses have been simplified;
• more precise outer sheath details have been added;
• cable element tests and cable tests have been simplified by the use of tables instead of
text;
• Annex A on PMD has been removed, to avoid duplication with IEC TR 61282-3.

The text of this standard is based on the following documents:
CDV Report on voting
86A/1589/CDV 86A/1621/RVC
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all parts 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 publication will remain unchanged until
the stability date indicated on the IEC website under "http://webstore.iec.ch" in the data
related to the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates
that it contains colours which are considered to be useful for the correct
understanding of its contents. Users should therefore print this document using a
colour printer.
– 6 – IEC 60794-3:2014 © IEC 2014

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 standard. Also included are cables for
specialized use in sewers and in water and gas pipes.
For aerial application, this standard 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 be necessary. Moreover, this standard 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 standard 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, in whole or in part, are normatively referenced in this document and
are indispensable for its application. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any
amendments) applies.
IEC 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
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.
IEC 60794-1-1, Optical fibre cables – Part 1-1: Generic specification – General
IEC 60794-1-21, 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: Basic optical cable test procedures –
Environmental test methods
IEC 60794-1-23, Optical fibre cables – Part 1-23: 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 sheaths
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 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 abbreviations
For the purposes of this document, the terms, definitions, symbols and abbreviations given in
IEC 60794-1-1 apply.
4 Optical fibre
4.1 General
Optical fibre shall be used which meets the requirements of IEC 60793-2. The fibre type shall
be agreed between the customer and supplier.
___________
To be published.
– 8 – IEC 60794-3:2014 © IEC 2014
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
λ shall be less than the
For single-mode fibre, the cabled fibre cut-off wavelength
cc
operational 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. 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 below. 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 below.
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, Method E15. The
filled tube shall comply with IEC 60794-1-21, Method E14, 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.
– 10 – IEC 60794-3:2014 © IEC 2014
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
Number of fibres w h b p
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.

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.
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 specification 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.

– 12 – IEC 60794-3:2014 © IEC 2014
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 and/or dry-block 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 compound shall comply with IEC 60794-1-21, Method E15. The cable shall pass
the compound flow test of Method E14 of IEC 60794-1-21.
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 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.
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 2,0 % minimum well dispersed carbon black in accordance with
IEC 60811-607, unless otherwise 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
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,
c) 16,5 MPa for high-density polyethylene.
The measured values of elongation at break shall be not less than 300 %.
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 B shall be applied.

– 14 – IEC 60794-3:2014 © IEC 2014
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
+ 1
cable 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.
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.
Table 2 – Characteristics of different types of cable elements
Characteristics Family requirements Test methods Remarks
IEC 60794-3
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,
IEC 60811-203 slotted core and
ruggedized elements
Dimensions 5.6.1 IEC 60794-1-23 Ribbons
Methods G2, G3 or G4
Bend IEC 60794-1-23 Secondary coating, tight
Method G1 buffer, tube
Strippability 5.2 IEC 60793-1-32 Primary or secondary
fibre coatings and tight
buffers
Strippability 5.6.3.2 As agreed between Ribbon
supplier and manufacturer
Separability of individual 5.6.3.1 IEC 60794-1-23 Ribbon
fibres from ribbon Method G5
Kink 5.5 IEC 60794-1-23 Tube
Method G7
Torsion 5.6.3.3 IEC 60794-1-23 Ribbon
Method G6
Compound flow 5.5 IEC 60794-1-21, method Tube
E14
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 3. 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.

– 16 – IEC 60794-3:2014 © IEC 2014
Table 3 – Mechanical and environmental applicable tests
Characteristics Family Test methods Remarks
requirements
Tensile performance IEC 60794-1-21
Method E1
Sheath abrasion resistance IEC 60794-1-21
Method E2A
Crush IEC 60794-1-21
Method E3
Impact  IEC 60794-1-21
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
Method E13 specific shotgun
protection
Bending under tension IEC 60794-1-21
Method E18
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
Water penetration  IEC 60794-1-22 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
10 Quality assurance
It is the responsibility of the manufacturer to establish quality assurance by quality control
proc
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