IEC 60794-3-11:2010

IEC 60794-3-11 ®
Edition 2.0 2010-06
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Optical fibre cables –
Part 3-11: Outdoor cables – Product specification for duct, directly buried, and
lashed aerial single-mode optical fibre telecommunication cables

Câbles à fibres optiques –
Partie 3-11: Câbles extérieurs – Spécification de produit pour les câbles de
télécommunication à fibres optiques unimodales, destinés à être installés dans
des conduites, directement enterrés et en aériens ligaturés

All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by
any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either IEC or
IEC's member National Committee in the country of the requester.
If you have any questions about IEC copyright or have an enquiry about obtaining additional rights to this publication,
please contact the address below or your local IEC member National Committee for further information.

Droits de reproduction réservés. Sauf indication contraire, aucune partie de cette publication ne peut être reproduite
ni utilisée sous quelque forme que ce soit et par aucun procédé, électronique ou mécanique, y compris la photocopie
et les microfilms, sans l'accord écrit de la CEI ou du Comité national de la CEI du pays du demandeur.
Si vous avez des questions sur le copyright de la CEI ou si vous désirez obtenir des droits supplémentaires sur cette
publication, utilisez les coordonnées ci-après ou contactez le Comité national de la CEI de votre pays de résidence.

IEC Central Office
3, rue de Varembé
CH-1211 Geneva 20
Switzerland
Email: inmail@iec.ch
Web: www.iec.ch
About the IEC
The International Electrotechnical Commission (IEC) is the leading global organization that prepares and publishes
International Standards for all electrical, electronic and related technologies.

About IEC publications
The technical content of IEC publications is kept under constant review by the IEC. Please make sure that you have the
latest edition, a corrigenda or an amendment might have been published.
 Catalogue of IEC publications: www.iec.ch/searchpub
The IEC on-line Catalogue enables you to search by a variety of criteria (reference number, text, technical committee,…).
It also gives information on projects, withdrawn and replaced publications.
 IEC Just Published: www.iec.ch/online_news/justpub
Stay up to date on all new IEC publications. Just Published details twice a month all new publications released. Available
on-line and also by email.
 Electropedia: www.electropedia.org
The world's leading online dictionary of electronic and electrical terms containing more than 20 000 terms and definitions
in English and French, with equivalent terms in additional languages. Also known as the International Electrotechnical
Vocabulary online.
 Customer Service Centre: www.iec.ch/webstore/custserv
If you wish to give us your feedback on this publication or need further assistance, please visit the Customer Service
Centre FAQ or contact us:
Email: csc@iec.ch
Tel.: +41 22 919 02 11
Fax: +41 22 919 03 00
A propos de la CEI
La Commission Electrotechnique Internationale (CEI) est la première organisation mondiale qui élabore et publie des
normes internationales pour tout ce qui a trait à l'électricité, à l'électronique et aux technologies apparentées.

A propos des publications CEI
Le contenu technique des publications de la CEI est constamment revu. Veuillez vous assurer que vous possédez
l’édition la plus récente, un corrigendum ou amendement peut avoir été publié.
 Catalogue des publications de la CEI: www.iec.ch/searchpub/cur_fut-f.htm
Le Catalogue en-ligne de la CEI vous permet d’effectuer des recherches en utilisant différents critères (numéro de référence,
texte, comité d’études,…). Il donne aussi des informations sur les projets et les publications retirées ou remplacées.
 Just Published CEI: www.iec.ch/online_news/justpub
Restez informé sur les nouvelles publications de la CEI. Just Published détaille deux fois par mois les nouvelles
publications parues. Disponible en-ligne et aussi par email.
 Electropedia: www.electropedia.org
Le premier dictionnaire en ligne au monde de termes électroniques et électriques. Il contient plus de 20 000 termes et
définitions en anglais et en français, ainsi que les termes équivalents dans les langues additionnelles. Egalement appelé
Vocabulaire Electrotechnique International en ligne.
 Service Clients: www.iec.ch/webstore/custserv/custserv_entry-f.htm
Si vous désirez nous donner des commentaires sur cette publication ou si vous avez des questions, visitez le FAQ du
Service clients ou contactez-nous:
Email: csc@iec.ch
Tél.: +41 22 919 02 11
Fax: +41 22 919 03 00
IEC 60794-3-11 ®
Edition 2.0 2010-06
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Optical fibre cables –
Part 3-11: Outdoor cables – Product specification for duct, directly buried, and
lashed aerial single-mode optical fibre telecommunication cables

Câbles à fibres optiques –
Partie 3-11: Câbles extérieurs – Spécification de produit pour les câbles de
télécommunication à fibres optiques unimodales, destinés à être installés dans
des conduites, directement enterrés et en aériens ligaturés

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CODE PRIX U
ICS 33.180.10 ISBN 978-2-88910-974-6

– 2 – 60794-3-11 © IEC:2010
CONTENTS
FOREWORD. 4
1  Scope . 6
2  Normative references . 6
3  Terms, definitions and symbols . 7
3.1  Terms and definitions . 7
3.2  Symbols . 7
4  General information . 7
4.1  Overview . 7
4.2  General cable description . 7
4.2.1  Characteristics of optical fibre . 7
4.2.2  Characteristics of optical fibre cable elements . 8
4.2.3  Characteristics of optical fibre cables . 8
4.2.4  Environmental and product safety requirements . 8
4.3  Optical fibre splice-ability . 8
4.4  Testing . 9
4.4.1  General . 9
4.4.2  No change in attenuation . 9
4.4.3  No change in fibre strain . 9
5  Requirements for cabled single-mode optical fibres . 9
5.1  Fibre materials . 9
5.2  Optical requirements . 10
5.2.1  General . 10
5.2.2  Attenuation coefficient . 10
5.2.3  Attenuation discontinuities . 11
5.2.4  Cable cut-off wavelength . 11
5.2.5  Polarization mode dispersion (PMD) . 11
5.2.6  Group index . 12
6  Requirements for cable elements . 12
6.1  Element design . 12
6.1.1  General . 12
6.1.2  Modularity . 12
6.1.3  Fibre and element identification . 12
6.2  Element characteris t ics . 13
6.2.1  Ribbon . 13
6.2.2  Tube kinking . 13
7  Requirements for optical cables . 14
7.1  Cable construction . 14
7.1.1  General . 14
7.1.2  Cable core . 14
7.1.3  Anti-buckling and strength element splicing . 14
7.1.4  Cable element stranding . 14
7.1.5  Spliced fibres . 14
7.1.6  Spare fibres . 14
7.1.7  Cable sheath removal . 15
7.1.8  Armouring . 15

60794-3-11 © IEC:2010 – 3 –
7.2  Marking . 15
7.2.1  Sheath marking . 15
7.2.2  Identification marking . 15
7.2.3  Cable length marking . 16
7.3  Cable core materials . 16
7.3.1  Tube filling compound material (if required) . 16
7.3.2  Water-blocking material . 16
7.3.3  Cable material compatibility . 16
7.3.4  Tube material . 16
7.4  Cable sheath . 17
7.4.1  Sheath material . 17
7.4.2  Sheath thickness . 17
7.4.3  Outer cable diameter . 17
7.4.4  Moisture barrier . 17
7.4.5  Rodent resistant barrier . 17
7.5  Mechanical requirements . 17
7.5.1  General . 17
7.5.2  Bend . 17
7.5.3  Impact . 18
7.5.4  Crush . 18
7.5.5  Tensile performance . 19
7.5.6  Torsion . 20
7.5.7  Repeated bending . 20
7.6  Environmental requirements . 21
7.6.1  Temperature cycling . 21
7.6.2  Stripping force stability of cabled optical fibres . 22
7.6.3  Water penetration . 23
7.6.4  Environmental impact . 23
7.7  Electrical protection . 23
8  Quality assurance . 23
Annex A (informative) Guidance for ITU-T and IEC cabled fibre and fibre references . 24
Annex B (informative) Fibres . 25
Bibliography . . 27

Figure 1 – For all cycles except last . 21
Figure 2 – Last cycle . 21

Table 1 – Requirements for the attenuation coefficient of cabled fibre . 10
Table 2 – Colour for individual fibres or units (listed alphabetically) . 12
Table A.1 – ITU-T & IEC Cross reference . 24
Table B.1 – Dimensional attributes and measurement methods . 25
Table B.2 – Mechanical attributes and test methods . 26
Table B.3 – Transmission attributes and measurement methods . 26
Table B.4 – Environmental exposure tests . 26
Table B.5 – Attributes measured during or after environmental exposure . 26

– 4 – 60794-3-11 © IEC:2010
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
OPTICAL FIBRE CABLES –
Part 3-11: Outdoor cables –
Product specification for duct, directly buried, and lashed aerial
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,
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.
International Standard IEC 60794-3-11 has been prepared by subcommittee 86A: Fibres and
cables, of IEC technical committee 86: Fibre optics.
This second edition cancels and replaces the first edition published in 2007. It constitutes a
technical revision.
The main changes with respect to the previous edition are as follows:
– the title of the specification has been updated to include lashed applications;
– the fibres specification clause (subclause 5.2.2) has been enlarged to include fibre types
B6_a.
60794-3-11 © IEC:2010 – 5 –
This bilingual version, published in 2011-04, corresponds to the English version.
The text of this standard is based on the following documents:
FDIS Report on voting
86A/1314/FDIS 86A/1326/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.
The French version of this standard has not been voted upon.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all parts of IEC 60794 series, published under the general title Optical fibre cables,
can be found on the IEC website.
The committee has decided that the contents of this publication will remain unchanged until
the stability date indicated on the IEC web site under "http://webstore.iec.ch" in the data
related to the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates
that it contains colours which are considered to be useful for the correct
understanding of its contents. Users should therefore print this document using a
colour printer.
– 6 – 60794-3-11 © IEC:2010
OPTICAL FIBRE CABLES –
Part 3-11: Outdoor cables –
Product specification for duct, directly buried, and lashed aerial
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 supplement those of IEC 60794-3 and IEC 60794-3-10
Multimode fibre requirements are not addressed in this standard; 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 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 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
class B single-mode fibres
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 (all parts), Optical fibre cables – Part 3: Sectional specification – Outdoor cables

60794-3-11 © IEC:2010 – 7 –
IEC 60794-3-10, Optical fibre cables – Part 3-10: Outdoor cables – Family specification for
duct, directly buried and lashed aerial 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/TR 61931, Fibre optic – Terminology
IEC/TR 62000, Single mode fibre compatibility guidelines
3 Terms, definitions and symbols
3.1 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 61931 apply.
3.2 Symbols
The following symbols are used in this document:
cable cut-off wavelength
cc
d  outer cable diameter
SZ technique in which the lay reverses direction periodically.
4 General information
4.1 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 installation, 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
included in Annex C of IEC 60794-1-1.
NOTE Annex C of IEC 60794-1 should become a technical report.
4.2 General cable description
4.2.1 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 are described in IEC 60793-2-50. The fibre types featured in this specification are listed
below:
dispersion unshifted (B1.1, B1.3);
bending loss insensitive (B6);
dispersion shifted (B2);
– 8 – 60794-3-11 © IEC:2010
cut-off shifted (B1.2), non-zero dispersion (B4) - While cut-off shifted B1.2 fibre can be
used in terrestrial applications, it is mainly used in submarine applications;
wide-band non-zero dispersion-shifted (B5).
(See Annex A for ITU-T cabled optical fibre references).
4.2.2 Characteristics of optical fibre cable elements
Optical fibre cable elements such as buffer tubes (loose or not), 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 series as well as those
outlined in Clause 6 of this standard.
4.2.3 Characteristics of optical fibre cables
Optical fibre cables, for the intent of this standard, 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 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.
4.2.4 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 cables 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.
4.3 Optical fibre splice-ability
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 splicing 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 on active alignment splicers according to the current best
practices. Additional fibre compatibility guidelines are provided in IEC/TR 62000.

60794-3-11 © IEC:2010 – 9 –
NOTE 1 Higher maximum splice losses can be tolerated 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.
4.4 Testing
4.4.1 General
For all test procedures, the atmospheric conditions shall be (23 °C  5 °C, and 20 % to 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. The number of fibres to be tested shall be agreed upon between the
customer and supplier.
4.4.2 No change in attenuation
4.4.2.1 General
For some of the parameters specified in this standard, the objective is no change in
attenuation.
These parameters may be affected by measurement uncertainty arising from measurement
errors or calibration errors due to a lack of suitable reference standards. Acceptance criteria
shall be interpreted with respect to this consideration.
4.4.2.2 No change in attenuation - single-mode
The total uncertainty of measurement for this standard shall be   0,05 dB for attenuation or
0,05 dB/km for attenuation coefficient. Any measured value within this range shall be
considered as “no change in attenuation”.
The requirement for these parameters is indicated as “no change ( 0,05 dB)” or “no change
( 0,05 dB/km)”. By agreement between the customer and the supplier, minor deviation from
this limit may be accepted at some low frequency, e.g. less than 10 %. However, for
mechanical tests no deviation in excess of 0,15 dB shall be accepted. For environmental
tests, no deviation in excess of 0,10 dB/km shall be accepted.
4.4.3 No change in fibre strain
For some of the parameters specified in this standard, the objective is zero strain.
These parameters may be affected by measurement uncertainty arising from measurement
errors or calibration errors due to a lack of suitable reference standards. Acceptance criteria
shall be interpreted with respect to this consideration.
The total uncertainty of measurement for this standard shall be  0,05 % strain. Any
measured value within this range shall be considered as “zero”.
5 Requirements for cabled single-mode optical fibres
5.1 Fibre materials
Use optical fibre as specified in IEC 60793-2-50.

– 10 – 60794-3-11 © IEC:2010
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.
5.2 Optical requirements
5.2.1 General
All optical fibre transmission attributes shall comply with 5.4 of IEC 60793-2-50. Attributes of
the cabled fibre (attenuation, point discontinuity, 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 the informative Annex B.
5.2.2 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 the
customer and the supplier.
Table 1 – Requirements for the attenuation coefficient of cabled fibre
Fibre type (maximum attenuation in dB/km)
Wavelength B1.1 B1.2 B1.3 B2 B4 B5 B6_a
a
1 310 nm 0,40 NA 0,40 0,50 NA 0,40
b b
1 383 nm NA NA 0,40 NA NA NA 0,40

1 550 nm 0,35 0,30 0,30 0,35 0,35 0,35 0,30
c c c c c c c
1 625 nm 0,40 0,40 0,40 0,40 0,40 0,40 0,40

NA = Not applicable.
a
1 310 nm is not specified unless agreed otherwise between the customer and the supplier.
b
1383 nm attenuation is specified after hydrogen aging as per IEC 60793-2-50.
c
1625 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 1383 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 1625 nm transmission with the zero dispersion region below 1 460 nm.
B6_a: A bending loss insensitive fibre compatible with B1.3 fibre that is suitable for use in
the access networks, including inside buildings.

60794-3-11 © IEC:2010 – 11 –
Test procedure:
Measurements shall be made in accordance with IEC 60793-1-40 at room temperature (23 C
5 C).
5.2.3 Attenuation discontinuities
Point discontinuities / local variations representing non-reflective events shall be:  0,10 dB.
a) Test procedure:
Measurements shall be made in accordance with IEC 60793-1-40, method C (backscattering
technique).
b) Measurement variables:
Wavelength: 1 310 nm and/or 1 550 nm.
5.2.4 Cable cut-off wavelength
Cable cut-off wavelength  shall be:
cc
1 260 nm for fibre types B1.1 and B1.3;
cc
1 270 nm for fibre type B2;
cc
1 450 nm for fibre type B4 and B5;
cc
1 530 nm for fibre type B1.2;
cc
1 260 nm for fibre types B6_a.
cc
Test procedure:
Cut-off wavelength measurements shall be made in accordance with IEC 60793-1-44.
5.2.5 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
IEC 60794-3, Annex A.
The appropriate test method shall be selected from IEC 60793-1-48, which also describes the
statistical nature of PMD (see Introduction of IEC 60793-1-48):
– 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.

– 12 – 60794-3-11 © IEC:2010
5.2.6 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.
6 Requirements for cable elements
6.1 Element design
6.1.1 General
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.
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.
6.1.2 Modularity
The most common modularities are: 1, 2, 4, 6, 8, 10, 12, 24.
6.1.3 Fibre and element identification
6.1.3.1 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 the supplier.
Table 2 – Colour for individual fibres or units (listed alphabetically)
Colour
Black
Blue
Brown
Green
Grey
Orange
Pink
60794-3-11 © IEC:2010 – 13 –
Colour
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).
6.1.3.2 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.
6.2 Element characteristics
6.2.1 Ribbon
Optical fibre ribbons shall comply with IEC 60794-3.
6.2.2 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.

– 14 – 60794-3-11 © IEC:2010
7 Requirements for optical cables
7.1 Cable construction
7.1.1 General
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 the customer and the 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.
7.1.2 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.
7.1.3 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.
7.1.4 Cable element stranding
Optical fibre cable elements as described in Clause 6 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 the cable structure 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.
7.1.5 Spliced fibres
Spliced fibres in the factory length of a cable are not allowed, unless agreed between the
customer and the supplier.
7.1.6 Spare fibres
Optical fibre cables shall not contain spare fibres unless agreed between the customer and
the supplier.
60794-3-11 © IEC:2010 – 15 –
NOTE A spare fibre is a fibre which is added to a cable element in extension of the nominal fibre content of this
element.
7.1.7 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.
7.1.8 Armouring
For direct burial, armouring (metallic or non-metallic) may be required, depending on
mechanical and environmen
...