IEC 60794-1-307:2025

IEC 60794-1-307 ®
Edition 1.0 2025-03
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Optical fibre cables –
Part 1-307: Generic specification – Basic optical cable test procedures – Cable
element test methods – Tube kinking, method G7

Câbles à fibres optiques –
Partie 1-307: Spécification générique – Procédures fondamentales d’essai des
câbles optiques – Méthodes d’essai des éléments de câble – Pliure du tube,
méthode G7
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IEC 60794-1-307 ®
Edition 1.0 2025-03
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Optical fibre cables –
Part 1-307: Generic specification – Basic optical cable test procedures – Cable

element test methods – Tube kinking, method G7

Câbles à fibres optiques –
Partie 1-307: Spécification générique – Procédures fondamentales d’essai des

câbles optiques – Méthodes d’essai des éléments de câble – Pliure du tube,

méthode G7
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 33.180.10  ISBN 978-2-8327-0276-5

– 2 – IEC 60794-1-307:2025 © IEC 2025
CONTENTS
FOREWORD . 3
INTRODUCTION . 5
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 6
4 General requirements. 6
5 Method G7: Tube kinking . 6
5.1 Object . 6
5.2 Method G7A . 7
5.2.1 Sample . 7
5.2.2 Apparatus . 7
5.2.3 Procedure . 8
5.2.4 Requirements . 8
5.2.5 Details to be specified . 8
5.2.6 Details to be reported . 8
5.3 Method G7B . 9
5.3.1 Object . 9
5.3.2 Sample . 9
5.3.3 Apparatus . 9
5.3.4 Procedure . 10
5.3.5 Requirements . 11
5.3.6 Details to be specified . 11
5.3.7 Details to be reported . 11
Bibliography . 12

Figure 1 – Tube kinking test set-up method G7A . 7
Figure 2 – Tube kinking test set-up method G7B . 10
Figure 3 – Schematic representation of tube movement during tube kinking test set-up
method G7B. 11

Table 1 – Recommended parameters for the tube kinking test . 8

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
OPTICAL FIBRE CABLES –
Part 1-307: Generic specification – Basic optical cable test procedures –
Cable element test methods – Tube kinking, method G7

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
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Standardization (ISO) in accordance with conditions determined by agreement between the two organizations.
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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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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) IEC draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). IEC takes no position concerning the evidence, validity or applicability of any claimed patent rights in
respect thereof. As of the date of publication of this document, IEC had not received notice of (a) patent(s), which
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the latest information, which may be obtained from the patent database available at https://patents.iec.ch. IEC
shall not be held responsible for identifying any or all such patent rights.
IEC 60794-1-307 has been prepared by subcommittee 86A: Fibres and cables, of IEC technical
committee 86: Fibre optics. It is an International Standard.
This first edition partially cancels and replaces the second edition of IEC 60794-1-23 published
in 2019. This edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to
IEC 60794-1-23:2019:
a) renumbering of the existing test method G7 as G7A;
b) addition of test parameter L and calculated loop diameter D in Table 1 for method G7A;
c) addition of a new test procedure for tubes routed within installation devices and numbering
it as G7B.
– 4 – IEC 60794-1-307:2025 © IEC 2025
The text of this International Standard is based on the following documents:
Draft Report on voting
86A/2537/FDIS 86A/2548/RVD
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this International Standard is English.
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
described in greater detail at www.iec.ch/publications.
A list of all parts in the IEC 60794 series, published under the general title Optical fibre cables,
can be found on the IEC website.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under webstore.iec.ch in the data related to the
specific document. At this date, the document will be
• reconfirmed,
• withdrawn, or
• revised.
INTRODUCTION
This document contains method G7 of IEC 60794-1-23:2019, which will be withdrawn. The
system for optical fibre test methods has been restructured and renumbered.
The optical cable element test methods contained in IEC 60794-1-23:2019 will now be
individually numbered in the IEC 60794-1-3xx series. Each test method is now considered to
be an individual document rather than part of a multi-test method compendium. Full cross-
reference details are given in IEC 60794-1-2.

– 6 – IEC 60794-1-307:2025 © IEC 2025
OPTICAL FIBRE CABLES –
Part 1-307: Generic specification – Basic optical cable test procedures –
Cable element test methods – Tube kinking, method G7

1 Scope
This part of IEC 60794 describes test procedures used in establishing uniform requirements of
tubes for the mechanical property kinking.
This document applies to optical fibre cables for use with telecommunication equipment and
devices employing similar techniques, and to cables having a combination of both optical fibres
and electrical conductors.
Throughout the document, the wording "optical cable" can also include optical fibre units,
microduct fibre units, etc.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies.
For undated references, the latest edition of the referenced document (including any
amendments) applies.
IEC 60794-1-2, Optical fibre cables – Part 1-2: Generic specification – Basic optical cable test
procedures – General guidance
3 Terms and definitions
No terms and definitions are listed in this document.
ISO and IEC maintain terminology databases for use in standardization at the following
addresses:
• IEC Electropedia: available at https://www.electropedia.org/
• ISO Online browsing platform: available at https://www.iso.org/obp
4 General requirements
IEC 60794-1-2 is the reference guide to test methods of all types. It shall be considered for
general requirements and definitions.
5 Method G7: Tube kinking
5.1 Object
The purpose of this test is to determine the ability of tubes containing optical fibres to withstand
mechanical stresses encountered during cable installation and splicing. The test is carried out
on tubes taken from an optical cable. The goal is to determine if the tube shows no kink when
coiled in a storage area.
5.2 Method G7A
5.2.1 Sample
Tube containing fibres, with a length of at least L + 50 mm, shall be taken from an optical fibre
cable.
Five samples shall be tested, unless otherwise specified.
5.2.2 Apparatus
The apparatus consists of a testing device as shown in Figure 1.

Key
L length of tube under test
L distance between the tube clamping point of the movable clamp and the tube clamping point of the fixed clamp
at the start of the test
L moving distance (the length of which determines the reduction of the ellipse dimension)
The minimum diameter of the loop is not fixed by a curvature in the test equipment, but only controlled by the fixed
length L of the specimen and the moving length L.
Whilst the loop tends to form an ellipse rather than a perfect circle during the test, it is possible to simplify the
understanding of the test parameters considerably by assuming that a circle is formed. Based on this assumption,
the cable element loop diameter D (mm) can be calculated.
The minimum allowed loop diameter can be calculated by
D= –()LL–/L π
(1)
The fixed guideway ensures a defined position of the sample. A transparent cover allows the sample to be kept in
the same plane and observed whilst being tested. The distance between the two covers shall be typically three times
the tube diameter. Too great a distance will allow the tube to move sideways during the test and does not ensure
that the test is severe enough.
Figure 1 – Tube kinking test set-up method G7A
The recommended parameters for tube kinking are shown in Table 1.

– 8 – IEC 60794-1-307:2025 © IEC 2025
Table 1 – Recommended parameters for the tube kinking test
Nominal tube diameter L L L D
1 2
mm mm mm mm mm
≤ 3,1 350 100 60 60
3,1 < D ≤ 6,1 650 200 70 120
6,1 < D ≤ 10,1 1 050 300 120 200
Parameter "D" is not required to perform the kink test but is the calculated and rounded loop diameter by using
Formula (1).
5.2.3 Procedure
The test shall be carried out at standard atmospheric conditions.
The sample shall be marked with a length L and mounted in the test device as shown in
Figure 1, with the movable and fixed clamps separated by a distance L .
The moveable clamp shall be moved between positions 1 and 2 over a distance L and returned
to position 1 at a speed approximately 10 mm/s. This movement is one cycle. During the last
cycle, the sample shall remain in position 2 for 60 s.
The values of test parameters L, L , L and the number of cycles (five, unless stated otherwise)
1 2
should simulate the service deployment conditions. They shall be agreed between customer
and supplier.
NOTE 1 As a mechanical test, a typical minimum value for the tube loop diameter is 60 mm, since this aligns with
the minimum specified bend diameter for most classes of fibre and also represents a minimum practical value of
coiled tube loops within a joint or other connectivity plant.
NOTE 2 Using D = 60 mm, then L can be calculated (for tubes ≤ 3,1 mm) from Formula (1), which also yields the
value of 60 mm. Since the loop does form an ellipse, which makes the effective loop diameter in one plane much
more severe, it is possible that 60 mm is taken as the maximum length specified for the moving length, L. Lower
values can be specified.
NOTE 3 If this test is used to simulate installation of a tube within a joint, then the value for D can be replaced by
the available width within a joint.
5.2.4 Requirements
During the test, no kinking of the sample shall be visible.
5.2.5 Details to be specified
The detail specification shall include the following:
a) number of samples to be tested (five, unless otherwise specified in the relevant
specification);
b) lengths L, L , L (use L, L and L according to Table 1, unless otherwise specified in the
1 2 1 2
relevant specification);
c) number of cycles for movement L for each sample (if different from five)
5.2.6 Details to be reported
The test report shall include all the details specified in 5.2.5 and additionally the following:
a) pass or fail.
5.3 Method G7B
5.3.1 Object
The purpose of this test is to evaluate the ability of tubes containing optical fibres to withstand
mechanical stresses encountered during routing within enclosures, splice trays and splice
organizers as well as cable installation according to a predetermined bend radius. The test is
carried out on tubes taken from an optical cable.
5.3.2 Sample
Tubes containing fibres with a length of 1 m with a tolerance of ±10 %, shall be taken from an
optical fibre cable.
The test shall be performed on 5 samples or on the number of samples specified in the relevant
specification.
5.3.3 Apparatus
The apparatus consists of a testing device as shown in Figure 2.

– 10 – IEC 60794-1-307:2025 © IEC 2025

Key
A tube entry point
A tube exit point
L length of tube under test
W channel or vertical guides distance (inner edge diameter)
W plate length
The apparatus is designed so the channel or vertical guides shall be spaced to the larger of 2 times the specified
buffer tube minimum radius or 20 times the tube OD.
The minimum diameter of the loop is controlled by the fixed length L of the sample and W , the width of the channel.
1 1
The fixed guideway ensures a defined position of the sample. A transparent cover allows the sample to be kept in
the same plane and observed whilst being tested. The distance between the two covers shall be typically three times
the tube diameter. Too great a distance will allow the tube to move sideways during the test and does not ensure
that the test is severe enough.
Figure 2 – Tube kinking test set-up method G7B
5.3.4 Procedure
The test shall be carried out at standard atmospheric conditions, as defined in IEC 60794-1-2.
With one end of the buffer tube fixed at A , feed the tube into the apparatus at A forming an
2 1
in
...