IEC 60794-3-11:2007

• Abstract:

  Sets forth technical requirements and characteristics of single-mode optical fibre cables for duct and direct buried installation. The specified test methods, where applicable, are those referenced in IEC 60794-1-1 and described in detail in IEC 60794-1-2. The requirements of this specification are used in conjunction with IEC 60794-3 and IEC 60794-3-10.

• Status: Published
• Publication Date: 08-Aug-2007
• ICS: 33.180.10 - Fibres and cables
• Technical Committee: SC 86A - Fibres and cables
• Drafting Committee: PT 60794-3-11 - TC 86/SC 86A/PT 60794-3-11
• Current Stage: DELPUB - Deleted Publication
• Start Date: 16-Jun-2010
• Completion Date: 28-Aug-2026

• Revised: IEC 60794-3-11:2010 - Optical fibre cables - Part 3-11: Outdoor cables - Product specification for duct, directly buried, and lashed aerial single-mode optical fibre telecommunication cables
• Effective Date: 05-Sep-2023

Overview

IEC 60794-3-11:2007 is an international standard published by the International Electrotechnical Commission (IEC) that provides a detailed specification for outdoor single-mode optical fibre telecommunication cables. Specifically, it covers cables designed for installation in ducts and for direct burial. This standard ensures robust performance, reliability, and safety in harsh outdoor environments, addressing the technical requirements and characteristics of single-mode optical fibre cables used in telecommunication networks.

The standard is intended to be used in conjunction with related IEC standards IEC 60794-3 and IEC 60794-3-10, along with the referenced test methods in IEC 60794-1-1 and IEC 60794-1-2, ensuring comprehensive coverage of fibre cable construction, testing, and quality assurance.

Key Topics

• Cable Construction: Detailed guidelines on cable core design, element stranding, armouring, and sheath materials to provide mechanical strength and protection against environmental stresses.
• Optical Fibre Requirements: Specifications include attenuation coefficient, attenuation discontinuities, cut-off wavelength, polarization mode dispersion (PMD), and group index for single-mode fibres.
• Mechanical Performance: Requirements cover resistance to bending, impact, crushing, tensile strain, torsion, and repeated bending to ensure durability in duct and direct burial installations.
• Environmental Resistance: Temperature cycling, water penetration resistance, moisture barriers, rodent protection, and overall environmental impact are addressed to maintain cable performance under varied outdoor conditions.
• Marking and Identification: Clear directives for cable sheath marking, identification marking, and length indications for effective installation and maintenance.
• Material Compatibility: Standards for material selection including tube filling compounds, water-blocking materials, and sheath materials to ensure reliable operation and compatibility with other network components.
• Testing and Quality Assurance: Mandates comprehensive testing regimes following IEC procedures to validate optical, mechanical, and environmental performance throughout the lifecycle of the cable.

Applications

IEC 60794-3-11:2007 is essential for manufacturers, installers, and operators of single-mode optical fibre telecommunication networks intended for outdoor use in duct systems or direct burial. Typical applications include:

• Long-distance and metropolitan telecommunication infrastructure.
• High-capacity data transmission networks requiring reliable fibre optic connectivity.
• Underground fibre cable deployments in urban, suburban, and rural environments.
• Networks requiring robust mechanical and environmental protection to withstand soil pressure, moisture ingress, temperature variations, and rodent damage.
• Installation projects targeting telecommunications operators, internet service providers, and utility companies seeking conformity with international standards.

Using cables conforming to IEC 60794-3-11 ensures resilient network performance, reduces maintenance needs, and prolongs operational lifespan in demanding outdoor conditions.

Related Standards

• IEC 60794-3: General requirements for outdoor cables and constructions, providing the overarching framework for all outdoor fibre optic cables.
• IEC 60794-3-10: Specification for optical fibre cables suitable for duct installation.
• IEC 60794-1-1 and IEC 60794-1-2: Define test methods applicable to optical fibre cables, ensuring standardized measurement of optical and mechanical properties.
• ITU-T Recommendations: Industry references complementing IEC standards, especially for fibre attributes and telecommunication compatibility.

Summary

Adhering to IEC 60794-3-11:2007 provides confidence in the quality, durability, and performance of single-mode optical fibre cables for outdoor duct and direct buried installations. Its comprehensive specifications cover every aspect from fibre characteristics to cable construction and environmental resilience-critical for the demanding environments typical of modern telecommunication networks. Compliance with this standard supports global interoperability, network stability, and long-term infrastructure investment protection.

IEC 60794-3-11
Edition 1.0 2007-08
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Optical fibre cables –
Part 3-11: Outdoor cables – Detailed specification for duct and directly buried
single-mode optical fibre telecommunication cables

Câbles à fibres optiques –
Partie 3-11: Câbles extérieurs – Spécification particulière pour les câbles de
télécommunication à fibres optiques unimodales destinés à être installés
dans des conduites ou à être directement enterrés

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IEC 60794-3-11
Edition 1.0 2007-08
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Optical fibre cables –
Part 3-11: Outdoor cables – Detailed specification for duct and directly buried
single-mode optical fibre telecommunication cables

Câbles à fibres optiques –
Partie 3-11: Câbles extérieurs – Spécification particulière pour les câbles de
télécommunication à fibres optiques unimodales destinés à être installés
dans des conduites ou à être directement enterrés

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
U
CODE PRIX
ICS 33.180.10 ISBN 2-8318-9255-4

– 2 – 60794-3-11 © IEC:2007
CONTENTS
FOREWORD.4

1 Scope.6

2 Normative references .6

3 Terms and definitions .7

4 Symbols .7

5 General information.8

5.1 Overview .8
5.2 General cable description.8
5.2.1 Characteristics of optical fibre .8
5.2.2 Characteristics of optical fibre cable elements .8
5.2.3 Characteristics of optical fibre cables .8
5.2.4 Environmental and product safety requirements .9
5.3 Optical fibre spliceability .9
5.4 Testing .9
6 Requirements for cabled single-mode optical fibres.10
6.1 Fibre materials .10
6.2 Optical requirements .10
6.2.1 Attenuation coefficient .10
6.2.2 Attenuation discontinuities.11
6.2.3 Cable cut-off wavelength .12
6.2.4 Polarization mode dispersion (PMD) .12
6.2.5 Group index.12
7 Requirements for cable elements .12
7.1 Element design .12
7.1.1 Modularity .13
7.1.2 Fibre and element identification .13
7.2 Element characteristics .14
7.2.1 Ribbon.14
7.2.2 Tube kinking.14
8 Requirements for optical cables.14
8.1 Cable construction .14

8.1.1 Cable core.15
8.1.2 Anti-buckling and strength element splicing .15
8.1.3 Cable element stranding.15
8.1.4 Spliced fibres .15
8.1.5 Spare fibres.15
8.1.6 Cable sheath removal.15
8.1.7 Armouring.15
8.2 Marking .16
8.2.1 Sheath marking .16
8.2.2 Identification marking .16
8.2.3 Cable length marking.16
8.3 Cable core materials .17
8.3.1 Tube filling compound material (if required) .17
8.3.2 Water-blocking material .17

60794-3-11 © IEC:2007 – 3 –
8.3.3 Cable material compatibility.17

8.3.4 Tube material .17

8.4 Cable sheath .17

8.4.1 Sheath material .17

8.4.2 Sheath thickness .17

8.4.3 Outer cable diameter .18

8.4.4 Moisture barrier .18

8.4.5 Rodent resistant barrier .18

8.5 Mechanical requirements.18

8.5.1 Cable bend.18

8.5.2 Impact .19
8.5.3 Crush .19
8.5.4 Tensile performance.20
8.5.5 Torsion .21
8.5.6 Repeated bending .21
8.6 Environmental requirements .22
8.6.1 Temperature cycling .22
8.6.2 Stripping force stability of cabled optical fibres .23
8.6.3 Water penetration.23
8.6.4 Environmental impact .23
8.7 Electrical protection.23
8.7.1 Continuity of metallic members.23
8.7.2 Lightning damage susceptibility .23
9 Quality assurance.23

Annex A (informative) Guidance for ITU-T and IEC cabled fibre and fibre references.24
Annex B (informative) Fibres.26

Bibliography.28

Figure 1 – Definition of the different temperatures .22

Table 1 – Attenuation coefficient.11

Table 2 – Colour for individual fibres or units (listed alphabetically) .13
Table A.1 – IEC and ITU cross-reference.25
Table B.1 – Dimensional attributes and measurement methods .26
Table B.2 – Mechanical attributes and test methods .27
Table B.3 – Transmission attributes and measurement methods .27
Table B.4 – Environmental exposure tests .27
Table B.5 – Attributes measured.27

– 4 – 60794-3-11 © IEC:2007
INTERNATIONAL ELECTROTECHNICAL COMMISSION

_____________
OPTICAL FIBRE CABLES
Part 3-11: Outdoor cables –
Detailed specification for duct and directly buried

single-mode optical fibre telecommunication cables

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,
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with the International Organization for Standardization (ISO) in accordance with conditions determined by
agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
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3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
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between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
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6) All users should ensure that they have the latest edition of this publication.
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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 60794-3-11 has been prepared by subcommittee 86A: Fibres and
cables, of IEC technical committee 86: Fibre optics.
The text of this standard is based on the following documents:
FDIS Report on voting
86A/1147/FDIS 86A/1165/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
This publication has been drafted in accordance with ISO/IEC Directives, Part 2.

60794-3-11 © IEC:2007 – 5 –
A list of all parts of the IEC 60794 series, published under the general title Optical fibre cables,

can be found on the IEC website.

This standard shall be used in conjunction with IEC 60794-3 and IEC 60794-3-10.

The committee has decided that the contents of this publication will remain unchanged until

the maintenance result date indicated on the IEC web site under "http://webstore.iec.ch" in

the data related to the specific publication. At this date, the publication will be

• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
– 6 – 60794-3-11 © IEC:2007
OPTICAL FIBRE CABLES
Part 3-11: Outdoor cables –
Detailed specification for duct and directly buried

single-mode optical fibre telecommunication cables

1 Scope
This part of IEC 60794 sets forth technical requirements and characteristics of single-mode
optical fibre cables for duct and direct buried installation.
This specification includes functional mechanical, environmental and optical requirements,
recommended features and test methods for assessing the product against the stated
requirements.
The specified test methods, where applicable, are those referenced in IEC 60794-1-1 and
described in detail in IEC 60794-1-2.
The requirements of this specification are used in conjunction with IEC 60794-3 and
IEC 60794-3-10.
)
Multimode fibre requirements are not addressed in this document; see IEC 60794-3-12 .
2 Normative references
The following referenced documents are indispensable for the application of this document.
For dated references, only the edition cited applies. For undated references, the latest edition
of the referenced document (including any amendments) applies.
IEC Guide 104, The preparation of safety publications and the use of basic safety publications
and group safety publications
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 60793-1-22, Optical fibres – Part 1-22: Measurement methods and test procedures –
Length measurement
IEC 60793-1-40, Optical fibres – Part 1-40: Measurement methods and test procedures –
Attenuation
___________
)
IEC 60794-3-12, Optical fibre cables - Part 3-12: Outdoor cables - Detailed specification for duct and directly
buried optical telecommunication cables for use in premises cabling

60794-3-11 © IEC:2007 – 7 –
IEC 60793-1-44, Optical fibres – Part 1-44: Measurement methods and test procedures – Cut-
off wavelength
IEC 60793-1-48, Optical fibres – Part 1-48: Measurement methods and test procedures –
Polarization mode dispersion
IEC 60793-2-50, Optical fibres – Part 2-50: Product specifications – Sectional specification for
single-mode class B fibres
IEC 60794 (all parts), Optical fibre cables

IEC 60794-1-1, Optical fibre cables – Part 1-1: Generic specification – General
IEC 60794-1-2, Optical fibre cables – Part 1-2: Generic specification – Basic optical cable test
procedures
IEC 60794-3, Optical fibre cables – Part 3: Sectional specification – Outdoor cables
IEC 60794-3-10, Optical fibre cables – Part 3-10: Outdoor cables – Family specification for
duct and directly buried optical telecommunication cables
IEC 60811-1-1, Common test methods for insulating and sheathing materials of electric
cables and optical cables – Part 1-1: Methods for general application – Measurement of
thickness and overall dimensions – Tests for determining the mechanical properties
IEC 62305 (all parts), Protection against lightning
IEC/TR 61931, Fibre optic – Terminology
IEC/TR 62000, Single-mode fibre compatibility guidelines
ITU-T G.652, Characteristics of a single-mode optical fibre and cable
3 Terms and definitions
For the purposes of this document, unless otherwise specified, the terms and definitions given
in IEC/TR 61931 apply.
4 Symbols
The following symbols are used in this document.
λ cable cut-off wavelength
cc
d  outer cable diameter
SZ technique in which the lay reverses direction periodically

– 8 – 60794-3-11 © IEC:2007
5 General information
5.1 Overview
Single-mode optical fibres are widely used for telecommunication purposes and are cabled to

satisfy the functional requirements of the installation environment. Further, cables placed into

ducts and sub-ducts may be installed using solely, or a combination of, pushing, pulling, and
air-assisted installation techniques. For duct installations, the environment and infrastructure
can be varied and may also involve the use of single and multiple sub-ducts. Directly buried

cables may be installed by a variety of methods such as ploughing and trenching with

different environments and infrastructure. This may require specific cable design solutions

based on multiple layers of armours and sheaths. It is recognised that certain designs of
cable for direct buried applications involving such solutions may also be suitable for duct
installation. The functional requirements and test methods featured in this specification are
based upon adherence to established and recognised installation techniques such as those
highlighted in Annex A (Guide to the installation of optical fibre cable) of IEC 60794-1-1.
5.2 General cable description
5.2.1 Characteristics of optical fibre
Single-mode optical fibres are classified according to their operational wavelength and
dispersion characteristics. The fibres covered by this specification are categorised as type B
and described in IEC 60793-2-50. The fibre types featured in this specification include
dispersion unshifted (B1.1, B1.3), dispersion shifted (B2), cut-off shifted (B1.2), non-zero
dispersion (B4), and anticipated fibre category for wide-band non-zero dispersion-shifted (B5).
(See Annex A for ITU-T cabled optical fibre references). While cut-off shifted B1.2 fibre can
be used in terrestrial applications, it is mainly used in submarine applications.
5.2.2 Characteristics of optical fibre cable elements
Optical fibre cable elements such as loose buffer tubes, slotted core, fibre ribbons, fibre
bundles and central/core tubes shall be suitably designed to provide adequate means of fibre
location, identification, modularity, protection during cable manufacture, installation and
termination. The structure of these elements and the materials used in their manufacture shall
not have any long-term detrimental effects on fibre performance during the service life of the
cable, splice enclosure and/or cabinet. To satisfy these functional requirements, the different
elements shall comply with the requirements of IEC 60794-3 as well as those outlined in
Clause 7 of this standard.
5.2.3 Characteristics of optical fibre cables
Optical fibre cables, for the intent of this document, are completed cable products as shipped
by the manufacturer typically on disposable reels. Such products do not require additional
assembly, or the use of additional materials or protection to meet the requirements contained
herein. Some assembly or added protection is usually required only where the cables are
terminated to other cables or equipment, and typically involve the use of an optical fibre
closure or other hardware to protect cable splice or connectorization points. The required
levels of protection for the fibre can be achieved by laying up or assembling the cable
elements in association with suitable strength and/or anti buckling members. These can be
either metallic in nature or non-metallic and positioned at the centre of the cable core or as
peripheral members in or underneath the outer cable sheath. The cable may also contain
moisture barrier tapes, metallic or non-metallic tapes, and water blocking or swellable
materials.
60794-3-11 © IEC:2007 – 9 –
5.2.4 Environmental and product safety requirements

IEC Guide 104 should be taken into account as far as possible. The materials of the cables in

contact with the environment shall not be hazardous to the environment and personnel.

It should be noted that the cable types specified by this standard are rarely accessible once

installed. Therefore, the risk of exposure to hazardous materials, if any, is mostly a concern in

the handling of the cable during manufacturing and installation. Additionally, the type of outer

sheath specified herein is generally considered to be non-toxic, therefore the risk to the

environment or personnel is minimal once properly installed.

This standard does not address the use of all types of cable materials that may be utilized in
various cable designs to support meeting the requirements unique to a specific type of special
application (e.g., very high temperatures or resistance to specific chemical attack). In such
cases, it is incumbent on the customer and supplier to agree on the requirements applicable
to such materials and cable designs, and to determine any special handling precautions or
instructions needed as a result of their use.
5.3 Optical fibre spliceability
All of the single-mode fibre types covered in this specification can readily achieve very low
splice loss levels using a range of commercially available techniques.
Typical bi-directional splice losses at 1 550 nm should be below 0,1 dB, with an average of
0,05 dB for fusion splices between fibres of the same category (B1-B1, or B2-B2, etc.)
performed by skilled operators according to the current best practices. Additional fibre
compatibility guidelines are provided in IEC/TR 62000.
NOTE 1 Higher maximum splice losses may occur without affecting the link transmission capability.
NOTE 2 Splices of fibres of the same category but different manufacturers and/or different production processes
do generally not exceed the above values.
NOTE 3 If fibres of different categories (B1-B2, B1-B4, etc.) are spliced, typically the splice loss is slightly higher
than with splices between fibres of the same category.
5.4 Testing
For all test procedures, the test conditions shall be the standard atmospheric conditions
(23° C ± 5 °C, and 20 % - 70 % relative humidity), unless otherwise specified. All measured
and computed values are to be rounded to the number of decimal places given in the
corresponding acceptance criteria for each requirement.

– 10 – 60794-3-11 © IEC:2007
The parameters specified in this standard may be affected by measurement uncertainty
arising either from measurement errors or calibration errors due to a lack of suitable

standards. Acceptance criteria shall be interpreted with respect to this consideration. The total

uncertainty of measurement for this standard shall be less than or equal to 0,05 dB for

attenuation or 0,05 dB/km for attenuation coefficient. Any measured value within this range,

either positive or negative, shall be considered as “no change in attenuation”.

Some of the mechanical and environmental tests in 8.5 and 8.6 can be performed on a short

sample length of cable, which is still an integral part of a longer length. Thus it becomes

possible to detect permanent changes in attenuation.

6 Requirements for cabled single-mode optical fibres
6.1 Fibre materials
Use optical fibre as specified in IEC 60793-2-50.
The coating surface shall be cleaned (e.g. from cable filling compounds) with only those
cleaning agents recommended by the fibre manufacturer. In any case, chlorine-based
cleaning agents shall not be used because of the health hazards involved.
6.2 Optical requirements
All optical fibre transmission attributes shall comply with the “transmission requirements” in
IEC 60793-2-50. Attributes of the cabled fibre (attenuation, point defects, polarization mode
dispersion, cable cut-off wavelength and group index) are specified in the following
subclauses. Other fibre attributes in IEC 60793-2-50 are summarized in Annex B.
6.2.1 Attenuation coefficient
The cabled fibre attenuation coefficients for the fibre types covered by this specification shall
meet the following requirements in Table 1, or as otherwise agreed upon between customer
and supplier.
60794-3-11 © IEC:2007 – 11 –
Table 1 ─ Attenuation coefficient

Fibre type (maximum attenuation in dB/km)

Wavelength B1.1 B1.2 B1.3 B2 B4 B5

1 310 nm 0,40 Not applicable 0,40 0,50 See Note 1 Not applicable

1 383 nm Not applicable Not applicable 0,40 Not applicable Not applicable Not applicable

(Note 2)
1 550 nm 0,35 0,30 0,30 0,35 0,35 0,35

1 625 nm 0,40 0,40 0,40 0,40 0,40 0,40

See Note 3 See Note 3 See Note 3 See Note 3 See Note 3 See Note 3
NOTE 1 1 310 nm is not specified unless agreed otherwise between customer and supplier.
NOTE 2 1 383 nm attenuation is specified after hydrogen ageing as per IEC 60793-2-50.
NOTE 3 1 625 nm attenuation values are optionally specified by the customer.
Fibre type definitions are provided in IEC 60793-2-50 for single-mode fibre. For informative purposes, they are
described below:
B1.1: Single-mode fibre with a zero dispersion between 1 300 nm to 1 324 nm, which is optimised for use in the
1 310 nm region and is compatible in the 1 550 nm region.
B1.2: Dispersion unshifted single-mode fibre that is optimised for 1 550 nm transmission with a cable cut-off
wavelength <1 530 nm.
B1.3: Single-mode fibre similar to B1.1 but has a low loss at 1 383 nm to provide additional compatibility between
1 360 nm to 1 460 nm.
B2: Dispersion shifted single-mode fibre with a zero dispersion in the 1 525 nm to 1 575 nm region.
B4: A non-zero dispersion shifted single-mode fibre (NZDSF) that is optimised for 1 550 nm transmission with the
zero dispersion outside the 1 530 nm to 1 565 nm region.
B5: A non-zero dispersion shifted single-mode fibre (NZDSF) that is optimised for 1 460 nm to 1 625 nm
transmission with the zero dispersion region below 1 460 nm.

Test procedure:
Measurements shall be made in accordance with IEC 60793-1-40 at room temperature
(23 °C + 5 °C).
6.2.2 Attenuation discontinuities

Point discontinuities / local variations representing non-reflective events shall be: ≤ 0,10 dB.
Test procedure:
Measurements shall be made in accordance with IEC 60793-1-40, method C (back scattering
technique).
Measurement variables:
Wavelength: 1 310 nm and/or 1 550 nm.

– 12 – 60794-3-11 © IEC:2007
6.2.3 Cable cut-off wavelength

Cable cut-off wavelength λ shall be:
cc
λ ≤ 1 260 nm for fibre types B1.1 and B1.3
cc
λ ≤ 1 260 nm for fibre type B2
cc
λ ≤ 1 450 nm for fibre type B4 and B5
cc
λ ≤ 1 530 nm for fibre type B1.2
cc
Test procedure:
Cut-off wavelength measurements shall be made in accordance with IEC 60793-1-44.
6.2.4 Polarization mode dispersion (PMD)
Polarization mode dispersion (PMD) is usually described in terms of a differential group delay
(DGD), which is the propagation time difference between the principal states of polarization of
an optical signal. PMD in cabled fibres and optical components causes an optical pulse to
spread in the time domain, which may impair the performance of a long length and high bit
rate (e.g. 10 Gbit/s transport over 400 km) optical fibre system. For these systems, only the
following evaluation may be useful.
Concerning the statistical nature of PMD in installed cable links, reference is made to
Annex A of IEC 60794-3.
The appropriate test method shall be selected from IEC 60793-1-48, which also describes the
statistical nature of PMD (see introduction):
– For links > 400 km, the link design value (PMD ) shall be less than or equal to
Q
0,5
0,20 ps/km . Note, from ITU-T Recommendation G.652 Table I.2/, this maximum link
design value should allow the possibility of 3 000 km links at 10 Gbit/s and 80 km (to
200 km) at 40 Gbit/s.
– For links < 400 km, the link design value (PMD ) shall be less than or equal to
Q
0,5
0,50 ps/km . Note from ITU-T Recommendation G.652 Table I.2 /, this maximum link
design value should allow the possibility of 400 km links at 10 Gbit/s.
6.2.5 Group index
This parameter is used to determine the fibre length within cables or cable lengths (taking
construction into account) using IEC 60793-1-22, method B. The group index shall be given at
1 310 nm for B1.1, B1.3, and B2 fibres and at 1 550 nm for all fibres. The group index shall be

given at 1 625 nm for any cable specified for operation at 1 625 nm.
7 Requirements for cable elements
7.1 Element design
An optical fibre cable element is an assembly of optical fibres arranged in such a way to
maintain its structure both inside the cable and once the sheath is removed.
The design intent of a fibre optic cable element is to organize fibres so as to facilitate fibre
identification and to improve handling.

60794-3-11 © IEC:2007 – 13 –
Current cable designs may include the following fibre optic cable elements:

– tube(s);
– slotted core(s);
– fibre bundle(s);
– fibre ribbon(s);
– central / core tube.
7.1.1 Modularity
The most common modularities are: 1, 2, 4, 6, 8, 10, 12, 24.
7.1.2 Fibre and element identification
7.1.2.1 Fibre identification
The coated fibre or buffer shall be distinguishable by means of colour coding or positioning.
Fibre and cable units shall be distinguishable by means of numbering or colour coding. Cable
units are defined as structures within the cable that combines the fibres into groups. For
example, this can be accomplished by placing fibres inside a tube, wrapping them with a
thread, placing them in a ribbon, placing them inside a slot, or any other method that
combines a group of fibres into an identifiable unit. Standard colours listed below
alphabetically in Table 2 shall be used, as near as possible (reasonable match) to IEC 60304.
The colour code system is to be agreed upon between the customer and supplier.
Table 2 – Colour for individual fibres or units (listed alphabetically)
Colour
Black
Blue
Brown
Green
Grey
Orange
Pink
Red
Turquoise
Violet
White
Yellow
NOTE For units containing more
than 12 fibres, fibres should be
identified by combining the above
sequence with an added
identification (e.g. ring marking,
dashed mark, tracer or coloured
unit binders).
– 14 – 60794-3-11 © IEC:2007
7.1.2.2 Element identification

The optical fibre cable elements shall be identified uniquely. One method is by the same

colour code as for the fibre identification. The first twelve elements (1-12) are identical to the

first twelve fibre colours. The next groups of twelve elements shall be identified by combining

the twelve colour sequence with an added identification.

Further alternatives are
– printing the sequential number on the element,

– marker/reference system (e.g. first element blue, second element yellow, followed by other

elements uncoloured),
– marking of the slots or the ribs in slotted core construction,
– block-bar numbering.
7.2 Element characteristics
7.2.1 Ribbon
Optical fibre ribbons shall comply with IEC 60794-3.
7.2.2 Tube kinking
The resistance of stranded loose tube elements to kinking shall be tested in accordance with
IEC 60794-1-2, method G7.
Test conditions:
Number of cycles: 5
Length L = 100 mm for tube diameter: d < 2,0 mm
Length L = 70 mm for tube diameter: 2,0 mm < d < 2,8 mm
Length L = 50 mm for tube diameter: d > 2,8 mm
Length L1 = 350 mm
Length L2 = 100 mm
The sample may be smoothed using a hot air fan.
8 Requirements for optical cables

8.1 Cable construction
The cable construction shall ensure protection of fibres from damage during shipping, storage,
installation and use. It shall further ensure to maintain the optical characteristics of the fibres
within the specified limits during the entire lifetime of the cable.
The features and characteristics given in the following paragraphs are for all general
applications of the cables covered by this standard. Special applications may require
deviations from these characteristics, to be agreed between customer and supplier.
The cable manufacturer shall give a description of the cable and particularly the arrangements
of cable elements and the location and material of the strength members. The description may
include a schematic cross-sectional drawing.

60794-3-11 © IEC:2007 – 15 –
8.1.1 Cable core
Unless otherwise agreed, the cable core shall be longitudinally water-blocked which may be

achieved by gel, water swellable materials or other suitable materials.

8.1.2 Anti-buckling and strength element splicing

Splices are allowed in anti-buckling or strength elements if the mechanical requirements of
the cable are fulfilled (e.g. tensile strength and bending requirements).

Every anti-buckling and strength element splice shall have a strength of at least 80 % the
nominal strength of the relevant anti-buckling and strength elements. The diameter of a

spliced anti-buckling element shall not be greater than the nominal anti-buckling element
diameter.
8.1.3 Cable element stranding
Optical fibre cable elements as described in Clause 7 may be laid up according to the
following configurations:
– single optical element(s) without a stranding lay;
– multiple homogeneous optical elements using helical or reverse oscillating (SZ) lay
method;
– a number of hybrid configurations in loose tube(s), slotted core(s) or central core tube(s)
such as fibre bundles, ribbons or loose tubes.
Fillers, insulated copper wires such as pairs or quads may be laid up with the optical elements,
if required.
NOTE The intent of this requirement is that sufficient fibre length be available in to accomplish fibre routing and
splicing in mid-span access. SZ and single central elements are obvious solutions, but any construction meeting
this intent is acceptable.
8.1.4 Spliced fibres
Spliced fibres in the factory length are not allowed, unless agreed between customer and
supplier.
8.1.5 Spare fibres
Optical fibre cables shall not contain spare fibres unless agreed between the customer and
supplier.
NOTE A spare fibre is a fibre which is added to a cable element in extension of the nominal fibre content of this
element.
8.1.6 Cable sheath removal
The supplier shall provide an appropriate method for sheath removal, such as the provision of
one or two ripcords under the sheath.
8.1.7 Armouring
For direct burial, armouring (metallic or non-metallic) may be required, depending on
mechanical and environmental conditions as agreed between customer and supplier including
adapted mechanical cable requirements (see 8.5). Additional cable mechanical testing can be
agreed upon by the customer and supplier.

– 16 – 60794-3-11 © IEC:2007
8.2 Marking
8.2.1 Sheath marking
The cable shall be marked by one of the following methods: sintering, embossing, hot foil, ink-
jet, indent or imprinting.
The abrasion resistance of the sheath markings shall comply with IEC 60794-1-2, method E2B.

Depending on the cable marking method used, one of the following test methods shall be
used:
Method 1: Steel needle diameter d = 1,0 mm
Load: 4 N
Number of cycles: 100 to 300 cycles depending on customer requirement.
or
Method 2: Felt pad to consist of either 1) water soaked wool felt or 2) rayon felt with < 30 %
wool
Weight: ≥ 450 g
Number of cycles: 3
8.2.2 Identification marking
The markings on each length of cable shall be printed in accordance with customer and
supplier requirements. Unless specified otherwise, the print shall contain, at minimum, the
following:
– designation, e.g. words or graphic identifying cable as an “optical cable”;
– number of fibres;
– type of fibres (e.g. B1, etc.);
– name of the supplier or product brand name;
– year of manufacture.
8.2.3 Cable length marking
Unless otherwise agreed, the difference between the length printed by the length marker and
−1
the actual length shall not be more than % of the actual length. Other tolerances can be
allowed provided the cable length is assured by other means.

The cable shall have sequentially numbered length markings printed on the sheath at 1 m
intervals. Alternate length marking is also acceptable. The length marking shall not be reset to
zero for the entire length of cable. The length marking can start with a value different from
zero.
If agreed between customer and supplier, cables may be re-marked in accordance with the
following.
Defective marking may be removed and the cable re-marked with the same colour.

60794-3-11 © IEC:2007 – 17 –
Alternatively, the defective
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