IEC 60331-1:2009

Tests for electric cables under fire conditions - Circuit integrity - Part 1: Test method for fire with shock at a temperature of at least 830 °C for cables of rated voltage up to and including 0,6/1,0 kV and with an overall diameter exceeding 20 mm

IEC 60331-1:2009 specifies the test apparatus and procedure and gives the performance requirements, including recommended flame application times, for low voltage power cables of rated voltage up to and including 0,6/1,0 kV and control cables with a rated voltage which are required to maintain circuit integrity when subject to fire and mechanical shock under specified conditions. It is intended for use when testing cables of greater than 20 mm overall diameter.
NOTE 1 Cables of smaller diameter should be tested using the apparatus, procedure and requirements of IEC 60331-2. This standard describes the means of test specimen preparation, the continuity checking arrangements, the electrical testing procedure, the method of burning the cables and the method of shock production, and gives requirements for evaluating test results.
NOTE 2 Although the scope is restricted to cables with rated voltage up to and including 0,6/1,0 kV, the procedure may be used, with the agreement of the manufacturer and the purchaser, for cables with rated voltage up to and including 3,3 kV, provided that suitable fuses are used.
Annex A provides the method of verification of the burner and control system used for the test. Requirements are stated for an identification that may optionally be marked on the cable to signify compliance with this standard. This first edition of IEC 60331-1 cancels and replaces IEC 60331-12 (2002) and IEC 60331-31 (2002) to form one single standard. It has the status of a horizontal standard in accordance with IEC Guide 104.

Essais pour câbles électriques soumis au feu - Intégrité des circuits - Partie 1: Méthode d'essai au feu avec chocs pour les câbles de tension assignée au plus égale à 0,6/1,0 kV et de diamètre externe supérieur à 20 mm, à une température d'au moins 830 °C

La CEI 60331-1:2009 donne des précisions sur l'appareillage et la procédure d'essai et les exigences de performance, y compris des recommandations pour la durée des temps d'application de la flamme pour les câbles de puissance à basse tension, de tension assignée au plus égale à 0,6/1,0 kV, et les câbles de contrôle ayant une tension assignée, qui sont réputés conserver l'intégrité du circuit quand ils sont soumis à un incendie et à des chocs mécaniques dans des conditions spécifiées. Elle est prévue pour être utilisée pour essayer des câbles de diamètre externe supérieur à 20 mm.
NOTE 1 Pour les câbles de diamètre plus petit, il convient d'utiliser l'appareillage, la procédure et les exigences de la CEI 60331-2. Cette norme décrit les moyens de préparation de l'éprouvette d'essai, les dispositions de contrôle de la continuité du circuit, la procédure d'essai électrique, la méthode pour brûler les câbles et la méthode de production des chocs, et indique les exigences pour évaluer les résultats d'essai.
NOTE 2 Bien que le domaine d'application soit limité aux câbles de tension assignée au plus égale à 0,6/1,0 kV, par accord entre client et fournisseur, la procédure peut être utilisée pour des câbles de tension assignée au plus égale à 3,3 kV à condition d'utiliser des fusibles appropriés.
L'Annexe A fournit la méthode de vérification du brûleur et le système de contrôle utilisé pour l'essai. Les conditions requises sont indiquées pour une identification signifiant la conformité à la présente norme par un éventuel marquage sur le câble. Cette première édition de la CEI 60331-1 annule et remplace la CEI 60331-12 (2002) et la CEI 60331-31 (2002) pour établir une seule norme. Elle a le statut de norme horizontale conformément au IEC Guide 104.

General Information

• Status: Published
• Publication Date: 18-May-2009
• ICS: 13.220.40 - Ignitability and burning behaviour of materials and products
• ICS: 29.020 - Electrical engineering in general
• ICS: 29.060.20 - Cables
• Technical Committee: TC 20 - Electric cables
• Drafting Committee: WG 18 - TC 20/WG 18
• Current Stage: DELPUB - Deleted Publication
• Completion Date: 28-Mar-2018

Relations

• Revised: IEC 60331-1:2018 - Tests for electric cables under fire conditions - Circuit integrity - Part 1: Test method for fire with shock at a temperature of at least 830 °C for cables of rated voltage up to and including 0,6/1,0 kV and with an overall diameter exceeding 20 mm
• Effective Date: 05-Sep-2023

Standards Content (Sample)

IEC 60331-1


®

Edition 1.0 2009-05



INTERNATIONAL



STANDARD



NORME
INTERNATIONALE
GROUP SAFETY PUBLICATION
PUBLICATION GROUPÉE DE SÉCURITÉ
Tests for electric cables under fire conditions – Circuit integrity –
Part 1: Test method for fire with shock at a temperature of at least 830 °C for
cables of rated voltage up to and including 0,6/1,0 kV and with an overall
diameter exceeding 20 mm

Essais pour câbles électriques soumis au feu – Intégrité des circuits –
Partie 1: Méthode d’essai au feu avec chocs pour les câbles de tension assignée
au plus égale à 0,6/1,0 kV et de diamètre externe supérieur à 20 mm, à une
température d’au moins 830 °C


IEC 60331-1:2009

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IEC 60331-1


®

Edition 1.0 2009-05



INTERNATIONAL



STANDARD



NORME
INTERNATIONALE
GROUP SAFETY PUBLICATION
PUBLICATION GROUPÉE DE SÉCURITÉ
Tests for electric cables under fire conditions – Circuit integrity –
Part 1: Test method for fire with shock at a temperature of at least 830 °C for
cables of rated voltage up to and including 0,6/1,0 kV and with an overall
diameter exceeding 20 mm

Essais pour câbles électriques soumis au feu – Intégrité des circuits –
Partie 1: Méthode d’essai au feu avec chocs pour les câbles de tension
assignée au plus égale à 0,6/1,0 kV et de diamètre externe supérieur à 20 mm, à
une température d’au moins 830 °C


INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
T
CODE PRIX
ICS 13.220.40; 29.020; 29.060.20 ISBN 978-2-88910-124-5
® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale

---------------------- Page: 3 ----------------------
– 2 – 60331-1 © IEC:2009


CONTENTS


FOREWORD.4

INTRODUCTION.6


1 Scope.7

2 Normative references.7

3 Terms and definitions .8

4 Test conditions – Test environment.8

5 Test apparatus .8

5.1 Test equipment.8
5.2 Test ladder and mounting .12
5.3 Source of heat .12
5.3.1 Burner .12
5.3.2 Flow meters and flow rates .13
5.3.3 Verification .14
5.4 Shock producing device.14
5.5 Positioning of source of heat.15
5.6 Continuity checking arrangements .15
5.7 Fuses .15
6 Test specimen .15
6.1 Test specimen preparation.15
6.2 Test specimen mounting.16
7 Test procedure .17
7.1 Test equipment and arrangement.17
7.2 Electrical connections .17
7.3 Flame and shock application.19
7.4 Electrification.19
8 Performance requirement .20
8.1 Flame application time.20
8.2 Acceptance criteria .20
9 Retest procedure .20
10 Test report.20
11 Cable marking .20
Annex A (normative) Verification procedure for the source of heat .21

Annex B (informative) Guidance on the choice of recommended test apparatus .23
Bibliography .24

Figure 1 – Schematic diagram of test configuration.9
Figure 2 – Plan view of fire test equipment .10
Figure 3 – End elevation of fire test equipment (not to scale) .11
Figure 4 – Typical rubber bush for supporting the test ladder .12
Figure 5 – Burner face .13
Figure 6 – Schematic diagram of an example of a burner control system using
rotameters .14
Figure 7 – Example of method of mounting a larger diameter test specimen for test.16

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60331-1 © IEC:2009 – 3 –


Figure 8 – Detailed section of adjustable position of vertical ladder elements for

mounting a smaller diameter test specimen for test .17

Figure 9 – Basic circuit diagram .19


Figure A.1 – Temperature measuring arrangement .21

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– 4 – 60331-1 © IEC:2009


INTERNATIONAL ELECTROTECHNICAL COMMISSION

____________



TESTS FOR ELECTRIC CABLES UNDER FIRE CONDITIONS –

CIRCUIT INTEGRITY –



Part 1: Test method for fire with shock at a temperature of at least 830 °C

for cables of rated voltage up to and including 0,6/1,0 kV and

with an overall diameter exceeding 20 mm




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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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 60331-1 has been prepared by IEC technical committee 20: Electric
cables.
This first edition of IEC 60331-1 cancels and replaces IEC 60331-12 (2002) and IEC 60331-31
(2002) to form one single standard.
The text of this standard is based on the following documents:
FDIS Report on voting
20/1049/FDIS 20/1053/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.

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60331-1 © IEC:2009 – 5 –


This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.


It has the status of a group safety publication in accordance with IEC Guide 104.


A list of all the parts in the IEC 60331 series, under the general title Tests for electric cables

under fire conditions – circuit integrity, can be found on the IEC website.


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.

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– 6 – 60331-1 © IEC:2009


INTRODUCTION


IEC 60331 consists of the following parts under the general title: Tests for electric cables under

fire conditions – Circuit integrity:


Part 1: Test method for fire with shock at a temperature of at least 830 °C for cables of

rated voltage up to and including 0,6/1,0 kV and with an overall diameter exceeding

20 mm

Part 2: Test method for fire with shock at a temperature of at least 830 °C for cables of

rated voltage up to and including 0,6/1,0 kV and with an overall diameter not

exceeding 20 mm

Part 3: Test method for fire with shock at a temperature of at least 830 °C for cables of
rated voltage up to and including 0,6/1,0 kV tested in a metal enclosure
Part 11: Apparatus – Fire alone at a flame temperature of at least 750 °C
Part 21: Procedures and requirements – Cables of rated voltage up to and including
0,6/1,0 kV
Part 23: Procedures and requirements – Electric data cables
Part 25: Procedures and requirements – Optical fibre cables
NOTE Parts 21, 23 and 25 relate to fire-only conditions at a flame temperature of at least 750 °C.
Since its first edition (1970), IEC 60331 has been extended and has introduced a range of test
apparatus in order that a test may be carried out on large and small power, control, data and
optical fibre cables.
Successful tests carried out in accordance with this standard will enable an identification to be
marked on the product.

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60331-1 © IEC:2009 – 7 –


TESTS FOR ELECTRIC CABLES UNDER FIRE CONDITIONS –

CIRCUIT INTEGRITY –



Part 1: Test method for fire with shock at a temperature of at least 830 °C

for cables of rated voltage up to and including 0,6/1,0 kV and

with an overall diameter exceeding 20 mm








1 Scope
This part of IEC 60331 specifies the test apparatus and procedure and gives the performance
requirements, including recommended flame application times, for low voltage power cables of
rated voltage up to and including 0,6/1,0 kV and control cables with a rated voltage which are
required to maintain circuit integrity when subject to fire and mechanical shock under specified
conditions. It is intended for use when testing cables of greater than 20 mm overall diameter.
NOTE 1 Cables of smaller diameter should be tested using the apparatus, procedure and requirements of
IEC 60331-2.
This standard describes the means of test specimen preparation, the continuity checking
arrangements, the electrical testing procedure, the method of burning the cables and the
method of shock production, and gives requirements for evaluating test results.
NOTE 2 Although the scope is restricted to cables with rated voltage up to and including 0,6/1,0 kV, the procedure
may be used, with the agreement of the manufacturer and the purchaser, for cables with rated voltage up to and
including 3,3 kV, provided that suitable fuses are used.
Annex A provides the method of verification of the burner and control system used for the test.
Requirements are stated for an identification that may optionally be marked on the cable to
signify compliance with this standard.
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 60584-1, Thermocouples – Part 1: Reference tables
IEC 60269-3, Low-voltage fuses – Part 3: Supplementary requirements for fuses for use by
unskilled persons (fuses mainly for household and similar applications) – Examples of
standardized systems of fuses A to F
IEC Guide 104, The preparation of safety publications and the use of basic safety publications
and group safety publications

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– 8 – 60331-1 © IEC:2009



3 Terms and definitions


For the purposes of this document, the following terms and definitions apply.


3.1

circuit integrity

ability of an electric cable to continue to operate in a designated manner whilst subjected to a

specified flame source for a specified period of time under specified conditions.



4 Test conditions – Test environment
3
The test shall be carried out in a suitable chamber, of minimum volume 10 m , with facilities for
disposing of any noxious gases resulting from burning. Sufficient ventilation shall be available
to sustain the flame for the duration of the test.
NOTE 1 Guidance on the choice of suitable chambers is given in Annex B.
The chamber and test apparatus shall be at a temperature of between 10 °C and 40 °C at the
start of each test.
The same ventilation and shielding conditions shall be used in the chamber during both the
verification and cable test procedures.
NOTE 2 The test given in this standard may involve the use of dangerous voltages and temperatures. Suitable
precautions should be taken against the risk of shock, burning, fire and explosion that may be involved, and against
any noxious fumes that may be produced.
5 Test apparatus
5.1 Test equipment
The test equipment shall consist of the following:
a) a test ladder, on to which the test specimen is mounted, comprising a steel framework
fastened to a rigid support as described in 5.2;
b) a source of heat comprising a horizontally mounted ribbon burner as described in 5.3;
c) a shock-producing device as described in 5.4;
d) a test wall equipped with thermocouples for verification of the source of heat as described
in Annex A.

e) a continuity checking arrangement as described in 5.6
f) fuses as described in 5.7
A general arrangement of the test equipment is shown in Figures 1, 2 and 3.

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60331-1 © IEC:2009 – 9 –


Dimensions in millimetres











IEC  814/09

Key
1 shock producing device 5 fixed vertical elements of test ladder

2 steel test ladder 6 adjustable vertical elements of test ladder
3 rubber bush 7 RIGID support framework
4 ribbon gas burner P plane of adjustment
Figure 1 – Schematic diagram of test configuration

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– 10 – 60331-1 © IEC:2009




Dimensions in millimetres








IEC  815/09



Key
1 entry for air 4 horizontal steel test ladder
2 rubber bush 5 entry for propane gas
3 support framework
Figure 2 – Plan view of fire test equipment

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60331-1 © IEC:2009 – 11 –


Dimensions in millimetres











IEC  816/09



Key
1 shock producing device H horizontal distance of metal enclosure centre line from burner face
2 steel test ladder vertical distance of metal enclosure centre line from centre line of burner
V
3 gas burner
4 centre line of burner face
Figure 3 – End elevation of fire test equipment (not to scale)

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– 12 – 60331-1 © IEC:2009


5.2 Test ladder and mounting

The test ladder shall consist of a steel framework as shown in Figure 1. The two central vertical

elements of the ladder shall be adjustable in order to accommodate different sizes of cable

under test. The test ladder shall be (1 200 ± 100) mm long and (600 ± 50) mm high, and the

total mass of the test ladder shall be (18 ± 1) kg. Ballast, if required, shall be placed on the

steel supports.


NOTE 1 Angle iron approximately 45 mm wide and 6 mm thick, with suitable slots cut to allow for fixing of the

bolts or saddles, has been found to be a suitable material for construction of the ladder.

Each horizontal element shall have a mounting hole not more than 200 mm from each end, the

exact position and diameter being determined by the particular supporting bush and supporting
framework used. The test ladder shall be fastened to a rigid support by four bonded rubber
bushes of hardness 50–60 Shore A fitted between the horizontal steel elements of the ladder
and the support framework, as shown in Figures 1 and 2 so as to allow movement under
impact.
NOTE 2 A typical rubber bush, which has been found to be suitable, is shown in Figure 4.
Dimensions in millimetres
(dimensions without tolerances are approximate)


IEC  817/09

Figure 4 – Typical rubber bush for supporting the test ladder
5.3 Source of heat
5.3.1 Burner
The source of heat shall be a ribbon type propane gas burner with a nominal burner face length
of 500 mm with a Venturi mixer. A centre-feed burner is recommended. The nominal burner

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60331-1 © IEC:2009 – 13 –


face width shall be 10 mm. The face of the burner shall have three staggered rows of drilled

holes, nominally 1,32 mm in diameter and drilled at centres 3,2 mm from one another, as shown

in Figure 5. Additionally, a row of small holes milled on each side of the burner plate, to serve

as pilot holes for keeping the flame burning, is permitted.


Guidance on the choice of a recommended burner system is given in Annex B.




Dimensions in millimetres



IEC  818/09


NOTE Round holes, 1,32 mm in diameter, on centres 3,2 mm from one another, staggered in three rows and
centred on the face of the burner. Nominal burner face length 500 mm.
Figure 5 – Burner face
5.3.2 Flow meters and flow rates
Mass flow meters/controllers should be used as the means of controlling accurately the input
flow rates of fuel and air to the burner.
NOTE 1 Rotameter type flow meters may be used as an alternative, but are not recommended. Guidance on their
use, and the application of appropriate correction factors is given in IEC 60331-11:1999, Annex C.
NOTE 2 Figure 6 shows an example of a rotameter type system.
For the purposes of this test, the air shall have a dew point not higher than 0 °C.
The flow rates used for the test shall be as follows:

– air: (160 ± 8) l/min at reference conditions (1 bar and 20 °C) or (3 267 ± 163) mg/s ;
– propane: (10 ± 0,4) l/min at reference conditions (1 bar and 20 °C) or (319 ± 13) mg/s ;.
NOTE 3 The purity of the propane is not defined. Industrial grades that contain impurities are allowed provided
that the calibration requirements are achieved.

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– 14 – 60331-1 © IEC:2009













IEC  819/09



Key
1 regulator 9 flowmeters
2 piezoelectric igniter 10 venturi mixer
3 flame failure device 11 burner
4 control thermocouples 12 ball valve
5 propane cylinder 13 air flow
6 screw valve (6A = alternative position) 14 compressed air cylinder
7 pilot feed 15 screw valve on pilot feed
8 gas flow
Figure 6 – Schematic diagram of an example of
a burner control system using rotameters

5.3.3 Verification
The burner and control system shall be subject to verification following the procedure given in
Annex A.
5.4 Shock producing device
The shock producing device shall consist of a mild steel round bar (25,0 ± 0,1) mm in diameter
and (600 ± 5) mm long. The bar shall be freely pivoted about an axis parallel to the test ladder,
which shall be in the same horizontal plane as, and (200 ± 5) mm away from, the upper edge of
the ladder. The axis shall divide the bar into two unequal lengths, the longer length being (400
± 5) mm which shall impact the ladder. The bar shall drop under its own weight from an angle
+5
of (60 ) ° to the horizontal to strike the upper edge of the ladder at its midpoint as shown in
0

Figures 1 and 3.

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60331-1 © IEC:2009 – 15 –


5.5 Positioning of source of heat


The burner face shall be positioned in the test chamber so that it is at least 200 mm above the

floor of the chamber, or any solid mounting block, and at least 500 mm from any chamber wall.


By reference to the centre point of the test specimen (cable) to be tested, the burner shall be

positioned centrally at a horizontal distance of (H ± 2) mm from the burner face to the centre of

the test specimen and at a vertical distance of (V ± 2) mm from the burner horizontal central

plane to the centre of the test specimen, as shown in Figure 3.


The exact burner location to be used during cable testing shall be determined using the

verification procedure given in Annex A, where the values of H and V to be used shall be
determined.
NOTE The burner should be rigidly fixed to the framework during testing so as to prevent movement relative to the
test specimen.
5.6 Continuity checking arrangements
During the test, a current for continuity checking shall be passed through all conductors of the
test specimen. This shall be provided by a three-phase star connected or single-phase
transformer(s) of sufficien
...