IEC 60079-35-1:2011

Explosive atmospheres - Part 35-1: Caplights for use in mines susceptible to firedamp - General requirements - Construction and testing in relation to the risk of explosion

IEC 60079-35-1:2011 specifies requirements for the construction, testing and marking of caplights, including caplights with a point of connection for other equipment, for use in mines susceptible to firedamp (Group I - electrical equipment for explosive gas atmospheres as defined in IEC 60079-0). It deals only with the risk of the caplight becoming a source of ignition. The requirements for performance are in IEC 60079-35-2. This standard supplements and modifies the general requirements of IEC 60079-0 except as indicated in Table 1. This first edition cancels and replaces the second edition of IEC 62013-1, published in 2005, and constitutes a full technical revision. The main technical differences with respect to the previious edition are:
- the introduction of a means to achieve an equipment protection level (EPL) of Ma;
- the introduction of a single clause relating to equipment construction replacing individual specific clauses for the headpiece, battery, cable and external charging contacts;
- the deletion of statements relating to surface temperature, the rewording of statements relating to creepage and clearance and the addition of statements relating to thermal protection, electronic assemblies and additional circuitry;
- specific referenc to lithium cells;
- the addition of statements relating to battery recharging and protection against deep discharge.

Atmosphères explosives - Partie 35-1: Lampes-chapeaux utilisables dans les mines grisouteuses - Exigences générales - Construction et essais liés au risque d'explosion

La CEI 60079-35-1:2011 spécifie les exigences pour la construction, les essais et le marquage des lampes-chapeaux, y compris les lampes-chapeaux avec un point de connexion pour d'autres matériels, utilisables dans les mines grisouteuses (Groupe I - matériels électriques pour les atmosphères explosives gazeuses comme définies dans la CEI 60079-0). Elle traite uniquement du risque, présenté par une lampe-chapeau, de devenir une source d'inflammation. Les exigences d'aptitude à la fonction se trouvent dans la CEI 60079-35-2. La présente norme complète et modifie les exigences générales de la CEI 60079-0, excepté pour ce qui est indiqué dans le Tableau 1. Cette première édition annule et remplace la deuxième édition de la CEI 62013-1, parue en 2005, et constitue une révision technique générale. Les différences techniques principales par rapport à l'édition précédente sont:
- l'introduction d'un article unique relatif à la construction du matériel, remplaçant les différents articles spécifiques pour le projecteur, la batterie, le câble et les contacts extérieurs de charge;
- la suppression des indications concernant la température de surface, la reformulation des énoncés relatifs aux lignes de fuite et aux distances dans l'air, et l'adjonction d'indications concernant la protection thermique, les ensembles électroniques et les circuits additionnels;
- une référence spécifique aux éléments au lithium;
- l'adjonction d'indications concernant la recharge de la batterie et la protection contre la décharge sévère.

General Information

• Status: Published
• Publication Date: 25-May-2011
• ICS: 29.260.20 - Electrical apparatus for explosive atmospheres
• Technical Committee: TC 31 - Equipment for explosive atmospheres
• Drafting Committee: MT 60079-35 - TC 31/MT 60079-35
• Current Stage: PPUB - Publication issued
• Start Date: 26-May-2011
• Completion Date: 30-Jun-2011

Relations

• Replaces: IEC 62013-1:2005 - Caplights for use in mines susceptible to firedamp - Part 1: General requirements - Construction and testing in relation to the risk of explosion
• Effective Date: 05-Sep-2023

Overview

IEC 60079-35-1:2011 is an international standard published by the International Electrotechnical Commission (IEC) that specifies general requirements for the construction, testing, and marking of caplights designed for use in mines susceptible to firedamp. These caplights are electrical devices used in potentially explosive atmospheres, specifically within mining environments where firedamp (a mixture of methane and air) poses a risk of explosion.

This standard focuses exclusively on minimizing the risk of the caplight itself becoming a source of ignition in explosive atmospheres and supplements the general requirements outlined in IEC 60079-0, the base standard for electrical equipment in explosive gas atmospheres. The document sets essential rules to ensure caplights meet strict safety criteria and are properly marked and tested to mitigate explosion hazards.

IEC 60079-35-1:2011 cancels and replaces the former IEC 62013-1:2005 and incorporates a full technical revision that introduces protections such as the Equipment Protection Level (EPL) Ma, stronger construction requirements, and enhanced battery and thermal safety measures.

---

Key Topics

• Scope and Applicability: Covers construction, testing, and marking of caplights for mining environments with explosive atmospheres (Group I electrical equipment).
• Equipment Protection Levels (EPL): Defines how to achieve protection levels Mb (basic) and Ma (enhanced) for caplights, indicating their suitability for explosive atmospheres.
• Construction Requirements:
  • Integrated design of headpiece enclosures, battery compartments, cable, and external charging contacts.
  • Special consideration for lithium cells and other battery technologies.
  • Requirements for electrical insulation, thermal protection, and internal wiring.
• Testing Procedures:
  • Impact and drop tests to verify mechanical robustness.
  • Degree of protection testing against ingress of dust and water (IP rating).
  • Electrical and thermal ignition tests to prevent sparks or overheating.
  • Tests for cable sheath resistance against fatty acids and fire.
  • Battery leakage and overcurrent protection tests.
• Marking and Instructions:
  • Clear instructions and markings on caplights to ensure safe usage and compliance.
• Battery Safety:
  • Requirements for battery recharging circuits and protection against deep discharge.
  • Thermal and spark ignition compliance to prevent battery-related ignition risks.

---

Applications

IEC 60079-35-1 is crucial for manufacturers, engineers, and safety specialists involved in supplying and maintaining caplights used in mining operations vulnerable to firedamp explosions. By adhering to this standard, caplights can be:

• Safely operated in underground mines with explosive methane-air atmospheres.
• Reliably used for personal or group illumination without increasing explosion risk.
• Integrated with other electrical equipment demanding stringent explosion-proof protections.
• Certified to applicable safety marks, facilitating regulatory approvals and compliance in mining jurisdictions.

The standard supports the use of advanced technologies like lithium batteries and LEDs while ensuring increased safety levels, aiding mine operators in improving miner safety and meeting legislative safety requirements globally.

---

Related Standards

IEC 60079-35-1 operates within the broader framework of the IEC 60079 series, which covers equipment for explosive atmospheres:

• IEC 60079-0: General requirements applicable to all electrical equipment in explosive atmospheres; serves as the foundational standard.
• IEC 60079-35-2: Specifies the performance requirements of caplights, which complement the construction and testing requirements in Part 1.
• Other parts of IEC 60079 series concerning intrinsic safety, flameproof enclosures, and increased safety techniques ensure comprehensive explosion protection for mining electrical equipment.

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Keywords: IEC 60079-35-1, caplights, mining safety, explosive atmospheres, firedamp, explosion risk, equipment protection level, EPL Ma, electrical equipment, lithium batteries, LED lighting, construction requirements, testing standards, mining illumination safety, IEC 60079 series.

Standards Content (Sample)

IEC 60079-35-1 ®
Edition 1.0 2011-05
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Explosive atmospheres –
Part 35-1: Caplights for use in mines susceptible to firedamp – General
requirements – Construction and testing in relation to the risk of explosion

Atmosphères explosives –
Partie 35-1: Lampes-chapeaux utilisables dans les mines grisouteuses –
Exigences générales – Construction et essais liés au risque d'explosion

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IEC 60079-35-1 ®
Edition 1.0 2011-05
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Explosive atmospheres –
Part 35-1: Caplights for use in mines susceptible to firedamp – General
requirements – Construction and testing in relation to the risk of explosion

Atmosphères explosives –
Partie 35-1: Lampes-chapeaux utilisables dans les mines grisouteuses –
Exigences générales – Construction et essais liés au risque d'explosion

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CODE PRIX R
ICS 29.260.20 ISBN 978-2-88912-518-0

– 2 – 60079-35-1  IEC:2011
CONTENTS
FOREWORD . 4
INTRODUCTION . 6
1 Scope . 7
2 Normative references . 10
3 Terms and definitions . 10
4 Level of protection . 11
4.1 General . 11
4.2 Additional requirements for EPL “Ma” . 12
4.3 Thermal ignition compliance . 12
4.4 Spark ignition compliance . 12
5 Equipment construction . 12
5.1 Enclosures . 12
5.1.1 Headpiece enclosure . 12
5.1.2 Battery enclosure . 13
5.2 Cable . 13
5.3 External charging contacts . 13
5.4 Internal electrical connections . 13
5.5 Solid electrical insulating materials . 14
5.6 Internal wiring . 14
5.7 Supply of electrical power to other equipment . 14
5.8 Creepage and clearance distances . 14
5.9 Assembled electrical connection . 14
5.10 Thermal protection . 14
6 Overcurrent protection . 15
6.1 General . 15
6.2 Fuse or thermal circuit-breaker . 15
6.3 Resistive safety . 15
7 Cells and batteries . 16
8 Type verifications and tests . 16
8.1 Impact test . 16
8.2 Drop tests . 16
8.3 Degree of protection (IP) by enclosures . 16
8.4 Test to verify the non-ignition of a representative electrolytic gas mixture or
firedamp by fuse or thermal circuit-breaker . 17
8.5 Test to verify the non-ignition of a gas mixture by one strand of the cable
between the headpiece and the battery by thermal ignition . 17
8.6 Test to verify the resistance of the cable sheath to fatty acids . 17
8.7 Test to verify the resistance of the cable sheath to fire . 17
8.8 Test to verify the strength of cable entries, anchoring devices and cable . 17
8.9 Electrolyte leakage test for cells and batteries . 18
8.10 Current-limiting resistor test . 18
8.10.1 Current-limiting resistor not protected by a non-replaceable
resettable fuse . 18
8.10.2 Current-limiting resistor protected by a non-replaceable resettable
fuse . 18
8.10.3 Verification . 18

60079-35-1  IEC:2011 – 3 –
9 Marking . 18
9.1 General . 18
9.2 Examples of marking . 19
10 Instructions. 19

Figure 1 – Example of a caplight assembly . 11

Table 1 – Application or exclusion of specific clauses of IEC 60079-0 . 8

– 4 – 60079-35-1  IEC:2011
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
EXPLOSIVE ATMOSPHERES –
Part 35-1: Caplights for use in mines susceptible to firedamp –
General requirements – Construction and testing
in relation to the risk of explosion

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
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2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
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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) 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 60079-35-1 has been prepared by IEC technical committee 31:
Equipment for explosive atmospheres.
This first edition cancels and replaces the second edition of IEC 62013-1, published in 2005,
and constitutes a full technical revision.
In addition to the general revision and updating of IEC 62013-1, the main technical
differences with respect to the previous edition are as follows:
a) the inclusion of Table 1 listing the application or exclusion of specific clauses of
IEC 60079-0;
b) redrafting in the style of other IEC 60079 series standards;
c) the introduction of a means to achieve an equipment protection level (EPL) of Ma;

60079-35-1  IEC:2011 – 5 –
d) the introduction of a single clause relating to equipment construction replacing
individual specific clauses for the headpiece, battery, cable and external charging
contacts;
e) the deletion of statements relating to surface temperature, the rewording of statements
relating to creepage and clearance and the addition of statements relating to thermal
protection, electronic assemblies and additional circuitry;
f) specific reference to lithium cells;
g) the addition of statements relating to battery recharging and protection against deep
discharge.
The text of this standard is based on the following documents:
FDIS Report on voting
31/921/FDIS 31/938/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 the ISO/IEC Directives, Part 2.
A list of all parts of the IEC 60079-35 series, under the general title: Explosive atmospheres –
Caplights for use in mines susceptible to firedamp, 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.
– 6 – 60079-35-1  IEC:2011
INTRODUCTION
The general revision and updating of this second edition have been necessitated by the
advent of new technologies related to caplight design, in particular those related to lithium
batteries and light-emitting diode (LED) light sources, the growing practice of incorporating
electronic circuits and the introduction of intrinsically safe caplights which can be certified
without reference to performance requirements. It is intended that there should be a stronger
link between Part 1 (Construction) and Part 2 (Performance) of this Standard by upgrading
the reference in the Scope from a note to a requirement.
In addition, as this standard is now to become part of the IEC 60079 series, changes have
been made to bring it more in line with others in the series by cross referencing. This has
enabled a reduction in the number and length of clauses in the standard.

60079-35-1  IEC:2011 – 7 –
EXPLOSIVE ATMOSPHERES –
Part 35-1: Caplights for use in mines susceptible to firedamp –
General requirements – Construction and testing
in relation to the risk of explosion

1 Scope
This part of IEC 60079-35 specifies requirements for the construction, testing and marking of
caplights, including caplights with a point of connection for other equipment, for use in mines
susceptible to firedamp (Group I – electrical equipment for explosive gas atmospheres as
defined in IEC 60079-0). It deals only with the risk of the caplight becoming a source of
ignition.
The requirements for performance are in IEC 60079-35-2.
This standard supplements and modifies the general requirements of IEC 60079-0 except as
indicated in Table 1. Where a requirement of this standard conflicts with a requirement of
IEC 60079-0, the requirements of this standard take precedence.
Compliance with this standard will provide an EPL of Mb (see 4.1 of this standard). If an EPL
of Ma is required, the caplight will need to conform to the requirements of 4.2 of this standard,
which in turn refers to IEC 60079-11.
It is expected that from time to time, caplights conforming to this standard (EPL Mb) will
operate in atmospheres where the firedamp exceeds statutory levels that require the
withdrawal of people from the high firedamp atmosphere to a non-hazardous area.
In designing equipment for operation in conditions other than those given above, this standard
may be used as guidance; however, additional testing may be required.
Where a caplight is assessed as intrinsically safe equipment, Ex ia, conforming to IEC 60079-
11 only the clauses/subclauses listed in 4.2 require application.
—————————
IEC 60079-35-2, Caplights for use in mines susceptible to firedamp – Part 2: Performance and other safety-
related matters (to be published).

– 8 – 60079-35-1  IEC:2011
Table 1 – Application or exclusion of specific clauses of IEC 60079-0
Clause of IEC 60079-0
IEC 60079-0
clause
a a
Ed. 5.0 Ed. 6.0
application
Clause/subclause title (normative)
(2007) (2011)
1 1 Scope Applies
2 2 Normative references Applies
3 3 Terms and definitions Applies
4 4 Equipment grouping Applies
5 5 Temperatures Applies
6.1 6.1 Requirements for all equipment – General Applies
6.2 6.2 Requirements for all equipment – Mechanical strength of equipment Applies
6.3 6.3 Requirements for all equipment – Opening times Excluded
6.4 6.4 Requirements for all equipment – Circulating currents Excluded
6.5 6.5 Requirements for all equipment – Gasket retention Applies
Requirements for all equipment – Electromagnetic and ultrasonic
6.6 6.6 Applies
energy radiating equipment
7 7 Non-metallic enclosures and non-metallic parts of enclosures Applies
8 8 Metallic enclosures and metallic parts of enclosures Applies
9 9 Fasteners Applies
10 10 Interlocking devices Applies
11 11 Bushings Excluded
12 12 Materials used for cementing Applies
13 13 Ex components Applies
14 14 Connection facilities and terminal compartments Applies
15 15 Connection facilities for earthing or bonding conductors Excluded
16 16 Entries into enclosures Applies
17 17 Supplementary requirements for rotating electrical machines Excluded
18 18 Supplementary requirements for switchgear Excluded
19 19 Supplementary requirements for fuses Excluded
Supplementary requirements for plugs and socket outlets and
20 20 Applies
connectors
21 21 Supplementary requirements for luminaires Excluded
22 22 Supplementary requirements for caplights and handlights Applies
23 23 Equipment incorporating cells and batteries Modified
24 24 Documentation Applies
25 25 Compliance of prototype or sample with documents Applies
26.1 26.1 Type tests – General Applies

60079-35-1  IEC:2011 – 9 –
Clause of IEC 60079-0
IEC 60079-0
clause
a a
Ed. 5.0 Ed. 6.0
application
Clause/subclause title (normative)
(2007) (2011)
26.2 26.2 Type tests – Test configuration Applies
26.3 26.3 Type tests – Tests in explosive test mixtures Applies
26.4 26.4 Type tests – Tests of enclosures Modified
26.5.1 26.5.1 Thermal tests – Temperature measurement Applies
26.5.2 26.5.2 Thermal tests – Thermal shock test Applies
26.5.3 26.5.3 Thermal tests – Small component ignition test Applies
26.6 26.6 Torque tests for bushings Excluded
26.7 26.7 Non-metallic enclosures or non-metallic parts of enclosures Applies
26.8 26.8 Thermal endurance to heat Applies
26.9 26.9 Thermal endurance to cold Applies
26.10 26.10 Resistance to light Excluded
26.11 26.11 Resistance to chemical agents for Group I electrical equipment Applies
26.12 26.12 Earth continuity Excluded
26.13 26.13 Surface resistance of parts of enclosures of non-metallic materials Applies
26.14 NR Charging tests Applies
26.15 26.14 Measurement of capacitance Applies
NR 26.15 Verification of ratings of ventilating fans Excluded
NR 26.16 Alternative qualification of elastomeric sealing O-rings Applies
27 27 Routine tests Applies
28 28 Manufacturer's responsibility Applies
29 29 Marking Modified
30 30 Instructions Applies
Applies – This requirement of IEC 60079-0 is applied without change.
Excluded – This requirement of IEC 60079-0 does not apply.
Modified – This requirement of IEC 60079-0 is modified as detailed in this standard.
NR – No requirements.
a
The clause number in this table is shown for information only. The applicable requirements of IEC 60079-0 are
identified by the clause title which is normative. This table was written against the specific requirements of the
sixth edition of IEC 60079-0:2011. The clause numbers for the previous edition are shown for information only.
This is to enable the General requirements of the fifth edition of IEC 60079-0:2007 to be used where necessary
with this part of IEC 60079. Where there were no requirements (indicated by NR) or there is a conflict between
requirements, the later edition requirements take precedence.

– 10 – 60079-35-1  IEC:2011
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 60050-426, International Electrotechnical Vocabulary – Part 426: Equipment for explosive
atmospheres
IEC 60050-845, International Electrotechnical Vocabulary (IEV) – Chapter 845: Lighting
IEC 60079-0, Explosive atmospheres – Part 0: Equipment – General requirements
IEC 60079-1, Explosive atmospheres – Part 1: Equipment protection by flameproof enclosures
"d"
IEC 60079-7, Explosive atmospheres – Part 7: Equipment protection by increased safety "e"
IEC 60079-11, Explosive atmospheres – Part 11: Equipment protection by intrinsic safety "i"
IEC 60127-2, Miniature fuses – Part 2: Cartridge fuse-links
IEC 60332-1-1, Tests on electric and optical fibre cables under fire conditions – Part 1-1: Test
for vertical flame propagation for a single insulated wire or cable – Apparatus
IEC 60332-1-2, Tests on electric and optical fibre cables under fire conditions – Part 1-2: Test
for vertical flame propagation for a single insulated wire or cable – Procedure for 1 kW pre-
mixed flame
IEC 60664-3, Insulation coordination for equipment within low-voltage systems – Part 3: Use
of coating, potting or moulding for protection against pollution
UL 1642, Standard for Lithium Batteries
3 Terms and definitions
For the purposes of this document, the terms and definitions in IEC 60079-0, IEC 60050-426
and IEC 60050-845 as well as the following apply.
3.1
battery enclosure
enclosure to contain the battery
3.2
caplight
equipment comprising a headpiece and rechargeable secondary cell(s)/battery supplied either
in separate enclosures connected together with a cable as a complete assembly (see
Figure 1) or in a single unit complete with security lanyard
3.3
light source
device serving as a source of illumination
3.4
filament lamp
light source that emits light by heating a filament

60079-35-1  IEC:2011 – 11 –
3.5
light-emitting diode
LED
semiconductor diode that emits light when conducting a current

Key
1 Belt loop 7 Auxiliary light source
2 Cover 8 Main light source
3 Battery enclosure 9 Switch knob
4 Cable 10 Reflector
5 Cap clip 11 Bezel ring
6 Headpiece 12 Light transmitting
protective cover
Figure 1 – Example of a caplight assembly
4 Level of protection
4.1 General
Equipment complying solely with this standard is suitable for use in Group I situations as
defined in Equipment grouping in IEC 60079-0, and has an equipment protection level (EPL)
“Mb”.
– 12 – 60079-35-1  IEC:2011
4.2 Additional requirements for EPL “Ma”
Equipment complying with the Group I requirements of IEC 60079-11, with a level of
protection “ia”, need only additionally comply with the following clauses of the current
standard:
− 5.9 Assembled electrical connection;
− 8.2 Drop tests;
− 8.3 Degree of protection (IP) by enclosures;
− 9 Marking;
− 10 Instructions.
4.3 Thermal ignition compliance
Equipment shall be constructed, assessed and tested in accordance with any specific type of
protection referenced in IEC 60079-0 as suitable for EPL “Mb”, so that no surface of
components, enclosures and wiring which may come into contact with the explosive
atmospheres shall become a source of thermal ignition.
4.4 Spark ignition compliance
All parts of the circuit where a deliberate connection or disconnection could release spark
ignition energy shall be protected in accordance with any specific type of protection
referenced in IEC 60079-0 as suitable for EPL “Mb”.
All parts of the circuit that are not separated in accordance with 5.8 shall be considered for
the spark ignition energy that may be released when the parts connect or disconnect.
However, the spark energy in the battery connection, switch, and lamp connection may be
protected as provided for in Clause 6.
5 Equipment construction
5.1 Enclosures
5.1.1 Headpiece enclosure
The headpiece enclosure shall be tested in accordance with 8.1 to 8.3. In addition the
headpiece shall meet the following requirements:
The light source shall be protected by a protective cover which is light transmitting and may
have a protective rim.
The light transmitting protective cover shall be fitted additionally with a guard if:
a) the free surface of the light transmitting protective cover exceeds 3 500 mm ; or
b) the light transmitting protective cover will not withstand the impact test without the guard;
or
c) the headpiece is not fitted with means to cut off automatically the power supply to all light
sources when either the light transmitting protective cover or the filament envelope
breaks; or
d) if the headpiece is fitted with one or more single filament lamps, either
1) there shall be a distance of at least 1 mm between a lamp in its correct operating
position and the light transmitting protective cover; or
2) the lamp(s) shall be held in such a manner that the power supply to the lamp(s) is cut
off automatically if the light transmitting protective cover breaks.

60079-35-1  IEC:2011 – 13 –
5.1.2 Battery enclosure
The battery enclosure shall be tested in accordance with 8.1 to 8.3. In addition the battery
enclosure shall meet the following requirements:
The pressure above atmospheric inside the battery enclosure and the cells shall not exceed
30 kPa (0,3 bar) except that in "sealed" cells, a higher pressure is permissible, but each cell
shall then be either provided with a pressure relief device or with the means to limit the
pressure to a value which can be contained by the cell, as specified by the manufacturer.
Unless the caplight manufacturer can demonstrate that the concentration of hydrogen in the
free volume of the battery enclosure cannot exceed 2 % by volume, the degassing apertures
of all cells shall be so arranged that escaping gases are not vented into any enclosure of the
equipment containing electrical or electronic components or connections.
5.2 Cable
The cable between the battery enclosure and the headpiece enclosure shall have a sheath
which is resistant to fatty acids and fire.
The cable sheath shall be tested for resistance to fatty acids in accordance with 8.6.
The cable sheath shall be tested for resistance to fire in accordance with 8.7.
For cable entries, each cable and its anchoring device shall comply with the tensile strength
test according to 8.8.
One strand of the caplight cable shall:
a) when tested in accordance with 8.5, not ignite the methane and air mixture, or
o
b) be shown by calculation, or reference to cable data, not to exceed 450 C under short
circuit condition with its overload protection in place.
Where overcurrent protection according to Clause 6 is provided wholly or partly by a fuse,
each individual strand of each cable conductor shall be capable of either:
c) carrying the currents specified in 6.2b) without melting within the time specified (when
tested without a fuse in circuit); or
d) carrying the currents specified in 6.2b) without melting before the fuse has ruptured (when
tested with a fuse in circuit).
Where the requirement is satisfied by testing with a fuse in circuit, only the particular type of
fuse used for the test shall be permitted for use in the caplight.
5.3 External charging contacts
Caplights which are recharged by means of external contacts shall include a mechanical or
electrical device preventing the withdrawal of current other than in accordance with 5.9 during
the use of the caplight. When the electrical device is not an infallible component (as defined in
IEC 60079-11, Components on which intrinsic safety depends), it shall be duplicated and
each component shall be rated such that the maximum battery-charging current is not more
than two-thirds of the rated current for the component.
5.4 Internal electrical connections
Other than spring contacts for filament lamps, internal electrical connections shall conform to
IEC 60079-7, Factory connections. Only the manufacturer’s recommended method(s) of
making electrical connections to filament lamps shall be used.

– 14 – 60079-35-1  IEC:2011
5.5 Solid electrical insulating materials
Solid electrical insulating materials shall conform to IEC 60079-7, Solid electrical insulating
materials.
5.6 Internal wiring
Internal wiring shall conform to IEC 60079-7, Wiring internal to apparatus.
5.7 Supply of electrical power to other equipment
Where the caplight is also used to supply electrical power to other equipment (internal or
external to the caplight) the other equipment shall not affect compliance with this standard
and shall comply with an appropriate type of protection and equipment protection level (EPL).
Where the other equipment is external, the connection facilities to that equipment shall meet
the requirements of IEC 60079-0, Connection facilities and terminal compartments or
Supplementary requirements for plugs and socket outlets and connectors.
The EPL of the interface shall be clearly identified in the documentation.
5.8 Creepage and clearance distances
All wiring connections and printed wiring boards which can affect the type of protection
afforded shall be considered to have infallible separations if they meet the following creepage
and clearance requirements:
– IEC 60079-7, Clearances and IEC 60079-7, Creepage distances; or
– 0,5 mm through solid insulation; or
– 0,5 mm under a conformal coating which shall seal the path between the conductors in
question against the ingress of moisture and pollution, and shall give an effective lasting
unbroken seal. It shall adhere to the conductive parts and to the insulating material. If the
coating is applied by spraying, two separate coats shall be applied.
A solder mask alone is not considered as a conformal coating, but can be accepted as one of
the two coats when an additional coat is applied, provided that no damage occurs during
soldering. Other methods of application require only one coat, for example dip coating,
brushing, or vacuum impregnating. A solder mask that meets the requirements of a Type 1
coating in accordance with IEC 60664-3 is considered as a conformal coating and an
additional coating is not required.
The manufacturer shall provide evidence of compliance with these requirements.
5.9 Assembled electrical connection
It shall not be possible to obtain a current greater than 50 mA and a voltage greater than 6 V
between any two accessible points of the caplight when assembled for use.
5.10 Thermal protection
Non-resettable thermal circuit-breakers can be used to provide protection for the electronic
components. These components shall be operated at no more than 2/3 of the manufacturer’s
rating in normal operation.
60079-35-1  IEC:2011 – 15 –
6 Overcurrent protection
6.1 General
Overcurrent protection shall be provided which effectively limits the discharge current or
energy to a level unlikely to cause an ignition of a flammable atmosphere. Such protection
shall be provided by one or more of 6.2 to 6.3.
Cells and batteries shall meet the requirements of IEC 60079-7, Primary and secondary
batteries with capacity up to 25 Ah, except where they meet the requirements of IEC 60079-
11, Spark ignition and surface temperature of cells and batteries.
6.2 Fuse or thermal circuit-breaker
Where the means of overcurrent protection is a fuse or thermal circuit-breaker, the caplight
shall be constructed in such a manner that:
– the nominal voltage shall be not greater than 6 V;
– the value of the current in normal use shall be not greater than 1,5 A, and
– the nominal rating of the lamp shall be not greater than 6 W.
The fuse or thermal circuit-breaker shall conform to the following requirements:
a) a fuse or thermal circuit-breaker not housed in an enclosure meeting the requirements of
IEC 60079-1 shall be protected so that, when tested according to 8.4, there is no ignition
of any surrounding gas mixture,
NOTE An example of such suitable protection is to encapsulate in accordance with IEC 60079-11, Fuses.
b) the fuse shall comply with IEC 60127-2 and additionally meet the following criteria.
The fusing or interrupting current and fusing or interrupting time shall be as small as possible
with regard to the current/time charging and discharging characteristics of the battery. The
following rules shall apply:
– fusing or interrupting time at 12 A ± 0,1 A: not more than 1 s, and
– fusing or interrupting time at 15 A ± 0,1 A: not more than 200 ms.
6.3 Resistive safety
The combination of the battery, the cable and the means of protection shall conform to the
requirements of intrinsic safety using the spark ignition test described in IEC 60079-11, Test
methods for spark ignition. During the spark ignition test where a fuse is provided, it shall be
replaced by an equivalent resistance of suitable rating to allow the test to be performed.
Alternatively, an assessment may be carried out in accordance with IEC 60079-11,
Assessment using reference curves and tables.
Where the means of overcurrent protection includes a resistor, it shall be connected into the
circuit as near to the battery terminals as possible. The resistor shall be of the metal or metal
oxide film type or of the single layer wire-wound type with mechanical protection to prevent
unwinding of the wire in the event of breakage, or any similar construction, which has a failure
mode that increases resistance. The resistors shall:
a) be operated at no more than 2/3 of the manufacturers rating in normal operation and meet
the requirements of IEC 60079-11 for an infallible current-limiting resistor, or
o
b) not exceed 450 C, or decrease in resistance by more than 10 % of its pre-test value or
flame or deform such that an adjacent conductor could short circuit the resistor when
subjected to current limiting resistor tests in 8.10. The temperature shall not adversely
affect the type of protection.

– 16 – 60079-35-1  IEC:2011
7 Cells and batteries
Only types of cells listed in IEC 60079-0, Equipment incorporating cells and batteries shall be
used.
Contrary to IEC 60079-0, Equipment incorporating cells and batteries, cells and batteries are
permitted to be connected in parallel in caplights provided the cell manufacturer permits the
proposed configuration and safety is not impaired. This should be documented and included
as part of the caplight manufacturer’s documentation.
Lithium cells shall not explode or cause a fire when tested according to UL 1642.
NOTE Cells that comply with the requirements of UL 1642 or other relevant safety standards are considered to
meet this requirement.
Cells shall be designed and manufactured so as to minimize the possibility of an internal short
circuit. For example, if separators are used they shall be constructed so as to prevent
electrical contact between the plates if these swell or fracture or if any part becomes
detached.
The connections to the battery shall remain secure, that is; there shall be no interruption of
the circuit, when the battery enclosure, including the battery, is subjected to the drop test in
8.2.
The cells shall be insulated from the battery enclosure and from each other if either of these
is metallic.
When batteries are tested in accordance with 8.9, there shall be no leakage of electrolyte
onto the blotting paper.
The battery shall be recharged or changed only in the non-hazardous area. Recharging is
only permitted within the safety limits specified by the manufacturer.
Where specified by the cell manufacturer, protection against deep discharge and individual
cell polarity reversal under normal operation shall be provided. Under normal operation the
discharge current shall not exceed that defined by the cell manufacturer.
8 Type verifications and tests
8.1 Impact test
Impact tests shall be carried out in accordance with IEC 60079-0, Resistance to impact, with
the values of impact based on the low risk of mechanical danger for Group I apparatus and
with the exception that the size of the individual openings of the guard shall be up to
3 500 mm .
8.2 Drop tests
Drop tests shall be carried out in accordance with IEC 60079-0, Drop test, with the exception
that the headpiece shall be dropped from a height of 2 m and the battery enclosure shall be
dropped from a height of 1 m.
8.3 Degree of protection (IP) by enclosures
The enclosures shall provide a degree of ingress protection against the ingress of dust and
water of at least IP54 and shall be carried out in accordance with IEC 60079-0, Degree of
protection (IP) by enclosures, with the exception that category 2 shall be used on battery
enclosures and their covers which need to be vented. The test shall be carried out with any

60079-35-1  IEC:2011 – 17 –
drain plugs and pressure relief devices in position. If there are drain holes which are normally
open, these shall be open for the test.
8.4 Test to verify the non-ignition of a representative electrolytic gas mixture or
firedamp by fuse or thermal circuit-breaker
A current of 15 A ± 1 A at nominal battery voltage is passed through fuse or circuit-breaker in
a mixture of hydrogen and oxygen containing from 66 % to 74 % by volume of hydrogen at
standard atmospheric pressure. The test is repeated on 10 fuses or circuit breakers.
8.5 Test to verify the non-ignition of a gas mixture by one strand of the cable
between the headpiece and the battery by thermal ignition
A fully charged caplight battery, complete with its overcurrent protection; is short-circuited by
a 50 mm length test piece of the smallest cross section strand of the cable conductor in a
mixture of methane and air containing 6,5 % ± 0,3 % by volume of methane. The test is
repeated on 10 samples of the smallest cross section strand of the cable conductor.
NOTE The test leads should be of length and cross sectional area such that they do not adversely reduce the
amount of battery current passing through the strand of wire being tested.
8.6 Test to verify the resistance of the cable sheath to fatty acids
A sample of the cable sheath, with the cores removed, about 80 mm long, shall be weighed
and then immersed in a mixture of fatty acids of commercial quality having the following
nominal composition by mass:
– oleic acid: 60 %
– stearic acid: 20 %
– palmitic acid: 20 %
In addition, a sample of the complete cable, of which the maximum diameter has been
measured before the test, about 300 mm long, bent into a U shape, shall be suspended in the
same mixture with its ends just above the mixture.
Both samples shall remain immersed in the mixture for 96 h ± 1 h at a temperature of 70 °C
± 1 °C, after which they shall be removed, wiped clean, cooled to room temperature and
reweighed or re-measured as applicable.
The increase in mass of the sample and the increase in diameter of the sample shall not
exceed the values specified below. In determining the increase in diameter the maximum
diameter shall be determined before and after the test and any increase calculated; the
maximum diameters before and after the test can be at different points on the sample:
– increase in mass: 50 %
– increase in diameter: 30 %
8.7 Test to verify the resistance
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