EN 60079-17:2007

SLOVENSKI STANDARD
01-januar-2008
1DGRPHãþD
SIST EN 60079-17:2003
SIST EN 61241-17:2005
(NVSOR]LYQHDWPRVIHUHGHO3UHJOHGRYDQMHLQY]GUåHYDQMHHOHNWULþQLKLQãWDODFLM
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Explosive atmospheres -- Part 17: Electrical installations inspection and maintenance
Explosionsfähige Atmosphäre - Teil 17: Prüfung und Instandhaltung elektrischer Anlagen
Atmosphères explosives -- Partie 17: Inspection et entretien des installations électriques
Ta slovenski standard je istoveten z: EN 60079-17:2007
ICS:
29.260.20 (OHNWULþQLDSDUDWL]D Electrical apparatus for
HNVSOR]LYQDR]UDþMD explosive atmospheres
91.140.50 Sistemi za oskrbo z elektriko Electricity supply systems
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN 60079-17
NORME EUROPÉENNE
September 2007
EUROPÄISCHE NORM
ICS 29.260.20 Supersedes EN 60079-17:2003 and EN 61241-17:2005
Incorporates corrigendum July 2008

English version
Explosive atmospheres -
Part 17: Electrical installations inspection and maintenance
(IEC 60079-17:2007)
Atmosphères explosives -  Explosionsfähige Atmosphäre -
Partie 17: Inspection et entretien Teil 17: Prüfung und Instandhaltung
des installations électriques elektrischer Anlagen
(CEI 60079-17:2007) (IEC 60079-17:2007)

This European Standard was approved by CENELEC on 2007-09-01. CENELEC members are bound to
comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European
Standard the status of a national standard without any alteration.

Up-to-date lists and bibliographical references concerning such national standards may be obtained on
application to the Central Secretariat or to any CENELEC member.

This European Standard exists in three official versions (English, French, German). A version in any other
language made by translation under the responsibility of a CENELEC member into its own language and
notified to the Central Secretariat has the same status as the official versions.

CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Cyprus, the
Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy,
Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia,
Slovenia, Spain, Sweden, Switzerland and the United Kingdom.

CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung

Central Secretariat: rue de Stassart 35, B - 1050 Brussels

© 2007 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. EN 60079-17:2007 E
Foreword
The text of document 31J/145/FDIS, future edition 4 of IEC 60079-17, prepared by SC 31J, Classification
of hazardous areas and installation requirements, of IEC TC 31, Equipment for explosive atmospheres,
was submitted to the IEC-CENELEC parallel vote and was approved by CENELEC as EN 60079-17 on
2007-09-01.
This European Standard supersedes EN 60079-17:2003 and 61241-17:2005.
The significant technical changes with respect to EN 60079-17:2003 are as follows:
– additional requirements for inspection and maintenance of electrical installations for combustible dusts
are included;
– knowledge, skills and competencies of "responsible persons", "technical persons with executive
function" and "operatives" are explained in new Annex B;
– Equipment Protection Levels (EPLs) have been introduced and are explained in the new Annex C.
The following dates were fixed:
– latest date by which the EN has to be implemented
at national level by publication of an identical
national standard or by endorsement (dop) 2008-06-01
– latest date by which the national standards conflicting
with the EN have to be withdrawn (dow) 2010-09-01
Annex ZA has been added by CENELEC.
The contents of the corrigendum of July 2008 have been included in this copy.
__________
Endorsement notice
The text of the International Standard IEC 60079-17:2007 was approved by CENELEC as a European
Standard without any modification.
In the official version, for Bibliography, the following notes have to be added for the standards indicated:
IEC 60079-6 NOTE  Harmonized as EN 60079-6:2007 (not modified).
IEC 60079-7 NOTE  Harmonized as EN 60079-7:2007 (not modified).
IEC 60079-18 NOTE  Harmonized as EN 60079-18:2004 (not modified).
IEC 60079-26 NOTE  Harmonized as EN 60079-26:2007 (not modified).
IEC 60079-28 NOTE  Harmonized as EN 60079-28:2007 (not modified).
IEC 60204-1 NOTE  Harmonized as EN 60204-1:2006 (modified).
__________
- 3 - EN 60079-17:2007
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications

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.

NOTE  When an international publication has been modified by common modifications, indicated by (mod), the relevant EN/HD
applies.
Publication Year Title EN/HD Year

1) 2)
IEC 60079-0 (mod) - Electrical apparatus for explosive gas EN 60079-0 2006
atmospheres -
Part 0: General requirements
1) 2)
IEC 60079-1 - Explosive atmospheres - EN 60079-1 2007
Part 1: Equipment protection by flameproof
enclosures "d"
1)
IEC 60079-2 - Explosive atmospheres - - -
Part 2: Equipment protection by pressurized
enclosure "p"
1) 2)
IEC 60079-7 - Explosive atmospheres - EN 60079-7 2007
Part 7: Equipment protection by Increased
safety "e"
1) 2)
IEC 60079-10 - Electrical apparatus for explosive gas EN 60079-10 2003
atmospheres -
Part 10: Classification of hazardous areas

1) 2)
IEC 60079-11 - Explosive atmospheres - EN 60079-11 2007
Part 11: Equipment protection by intrinsic
safety "i"
1) 2)
IEC 60079-14 - Electrical apparatus for explosive gas EN 60079-14 2003
atmospheres -
Part 14: Electrical installations in hazardous
areas (other than mines)
1) 2)
IEC 60079-15 - Electrical apparatus for explosive gas EN 60079-15 2005
atmospheres -
Part 15: Construction, test and marking of
type of protection "n" electrical apparatus

1) 2)
IEC 60079-19 - Explosive atmospheres - EN 60079-19 2007
Part 19: Equipment repair, overhaul and
reclamation
1) 2)
IEC 60364-6 (mod) - Low voltage electrical installations - HD 60364-6 2007
Part 6: Verification
IEC 61241 Series Electrical apparatus for use EN 61241 Series
in the presence of combustible dust

1) 2)
IEC 61241-1 - Electrical apparatus for use EN 61241-1 2004
in the presence of combustible dust - + corr. December 2006
Part 1: Protection by enclosures "tD"

1)
Undated reference.
2)
Valid edition at date of issue.

Publication Year Title EN/HD Year
1) 2)
IEC 61241-4 - Electrical apparatus for use EN 61241-4 2006
in the presence of combustible dust -
Part 4: Type of protection "pD"

1) 2)
IEC 61241-10 - Electrical apparatus for use EN 61241-10 2004
in the presence of combustible dust -
Part 10: Classification of areas where
combustible dusts are or may be present

1) 2)
IEC 61241-11 - Electrical apparatus for use EN 61241-11 2006
in the presence of combustible dust -
Part 11: Protection by intrinsic safety "iD"

IEC 61241-14 2004 Electrical apparatus for use EN 61241-14 2004
in the presence of combustible dust -
Part 14: Selection and installation

IEC 60079-17
Edition 4.0 2007-08
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Explosive atmospheres –
Part 17: Electrical installations inspection and maintenance

Atmosphères explosives –
Partie 17: Inspection et entretien des installations électriques

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
W
CODE PRIX
ICS 29.260.20 ISBN 2-8318-9294-5

– 2 – 60079-17 © IEC:2007
CONTENTS
FOREWORD.4
INTRODUCTION.6

1 Scope.7
2 Normative references .7
3 Terms and definitions .8
4 General requirements .10
4.1 Documentation .10
4.2 Qualification of personnel.10
4.3 Inspections.10
4.3.1 General .10
4.3.2 Grades of inspection.11
4.3.3 Types of inspection .11
4.4 Periodic inspections .12
4.4.1 Personnel .12
4.4.2 Fixed installations.12
4.4.3 Moveable equipment .12
4.5 Continuous supervision by skilled personnel .13
4.5.1 Concept.13
4.5.2 Objectives .13
4.5.3 Responsibilities .13
4.5.4 Frequency of inspection.14
4.5.5 Documents .14
4.5.6 Training .14
4.6 Maintenance requirements .15
4.6.1 Remedial measures and alterations to equipment.15
4.6.2 Maintenance of flexible cables.15
4.6.3 Withdrawal from service .15
4.6.4 Fastenings and tools .15
4.7 Environmental conditions .16
4.8 Isolation of equipment .16
4.8.1 Installations other than intrinsically safe circuits .16
4.8.2 Intrinsically safe installations .17
4.9 Earthing and equipotential bonding .18
4.10 Specific conditions of use.18
4.11 Movable equipment and its connections .18
4.12 Inspection schedules (Tables 1 to 4) .18
4.12.1 Equipment is appropriate to the EPL/zone requirements of the
location .18
4.12.2 Equipment group is correct.18
4.12.3 Equipment maximum surface temperature is correct.18
4.12.4 Equipment circuit identification .18
4.12.5 Cable gland .19
4.12.6 Type of cable is appropriate .19
4.12.7 Sealing .19
4.12.8 Fault loop impedance or earthing resistance.19

60079-17 © IEC:2007 – 3 –
4.12.9 Insulation resistance.19
4.12.10 Overload protection .19
5 Additional inspection schedule requirements .19
5.1 Type of protection "d" – Flameproof enclosure (see Table 1 and IEC 60079-1).19
5.1.1 Flameproof joints (see IEC 60079-1) .19
5.2 Type of protection "e" – Increased safety (see Table 1 and IEC 60079-7).20
5.2.1 Overloads.20
5.3 Type of protection "i" and "iD" – Intrinsic safety (see Table 2 and IEC 60079-11
or IEC 61241-11).20
5.3.1 General .20
5.3.2 Documentation .20
5.3.3 Labelling.20
5.3.4 Unauthorized modifications.21
5.3.5 Associated apparatus (safety interface) between intrinsically safe
and non-intrinsically safe circuits .21
5.3.6 Cables.21
5.3.7 Cable screens .21
5.3.8 Point-to-point connections .21
5.3.9 Earth continuity of non-galvanically isolated circuits .21
5.3.10 Earth connections to maintain the integrity of the intrinsic safety .21
5.3.11 Intrinsically safe circuit earthing and/or insulation.22
5.3.12 Separation between intrinsically safe and non-intrinsically safe
circuits.22
5.4 Type of protection "p" and "pD" – Pressurized enclosure (see Table 3 and
IEC 60079-2 or IEC 61241-4) .22
5.5 Type of protection "n" (see Table 1 or 2 and IEC 60079-15) .22
5.5.1 General .22
5.5.2 Restricted breathing enclosures .22
5.6 Type of protection "tD" – Protection by enclosure (see Table 4 and
IEC 61241-1).22
5.7 Types of protection "m" and "mD" (encapsulation), "o" (oil-immersion) and
"q" (powder-filling).22
6 Inspection schedules .23

Annex A (informative) Typical inspection procedure for periodic inspections .28
Annex B (normative) Knowledge, skills and competencies of "responsible persons",
"technical persons with executive function" and "operatives".29
Annex C (informative) Introduction of an alternative risk assessment method
encompassing “equipment protection levels” for Ex equipment .31

Bibliography.36

Table 1 – Inspection schedule for Ex "d", Ex "e" and Ex "n" installations (D = Detailed,
C = Close, V = Visual) .23
Table 2 – Inspection schedule for Ex "i", "iD" and "nL" installations.25
Table 3 – Inspection schedule for Ex "p" and "pD" installations.26
Table 4 – Inspection schedule for Ex "tD" installations .27
Table C.1 – Traditional relationship of EPLs to zones (no additional risk assessment) .33
Table C.2 – Description of risk of ignition protection provided .34

– 4 – 60079-17 © IEC:2007
INTERNATIONAL ELECTROTECHNICAL COMMISSION
___________
EXPLOSIVE ATMOSPHERES –
Part 17: Electrical installations inspection and maintenance

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 provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with an IEC Publication.
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 60079-17 has been prepared by subcommittee 31J: Classification
of hazardous areas and installation requirements, of IEC technical committee 31: Equipment
for explosive atmospheres.
This fourth edition cancels and replaces the third edition published in 2002 and constitutes a
technical revision.
The significant technical changes with respect to the previous edition are as follows:
• Additional requirements for inspection and maintenance of electrical installations for
combustible dusts are included.
• Knowledge, skills and competencies of "responsible persons", "technical persons with
executive function" and "operatives" are explained in new Annex B.
• Equipment Protection Levels (EPLs) have been introduced and are explained in the new
Annex C.
60079-17 © IEC:2007 – 5 –
The text of this standard is based on the following documents:
FDIS Report on voting
31J/145/FDIS 31J/148/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 series, under the general title Explosive atmospheres, 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.
– 6 – 60079-17 © IEC:2007
INTRODUCTION
Electrical installations in hazardous areas possess features specially designed to render them
suitable for operations in such atmospheres. It is essential for reasons of safety in those
areas that, throughout the life of such installations, the integrity of those special features is
preserved; they therefore require initial inspection and either
a) regular periodic inspections thereafter, or
b) continuous supervision by skilled personnel
in accordance with this standard and, when necessary, maintenance.
NOTE Correct functional operation of hazardous area installations does not mean, and should not be interpreted
as meaning, that the integrity of the special features referred to above is preserved.

60079-17 © IEC:2007 – 7 –
EXPLOSIVE ATMOSPHERES –
Part 17: Electrical installations inspection and maintenance

1 Scope
This part of IEC 60079 applies to users and covers factors directly related to the inspection
and maintenance of electrical installations within hazardous areas only, where the hazard may
be caused by flammable gases, vapours, mists, dusts, fibres or flyings.
It does not include:
• other fundamental installation and inspection requirements for electrical installations;
• the verification of electrical equipment;
• the repair and reclamation of explosion protected equipment (see IEC 60079-19).
This standard supplements the requirements of IEC 60364-6.
In the case of dusts, fibres or flyings  the level of housekeeping may influence the inspection
and maintenance requirements.
This standard is intended to be applied where there can be a risk due to the presence of
explosive gas or dust mixtures with air or combustible dust layers under normal atmospheric
conditions. It does not apply to
• underground mining areas,
• areas where a risk can arise due to the presence of hybrid mixtures,
• dusts of explosives that do not require atmospheric oxygen for combustion,
• pyrophoric substances.
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 60079-0, Explosive atmospheres – Part 0: Equipment – General requirements
IEC 60079-1, Explosive atmospheres – Part 1: Equipment protection by flameproof enclosures
"d"
IEC 60079-2, Explosive atmospheres – Part 2: Equipment protection by pressurized
enclosures "p"
IEC 60079-7, Explosive atmospheres – Part 7: Equipment protection by increased safety “e”
IEC 60079-10, Electrical apparatus for explosive gas atmospheres – Part 10: Classification of
hazardous areas
IEC 60079-11, Explosive atmospheres – Part 11: Equipment protection by intrinsic safety "i"

– 8 – 60079-17 © IEC:2007
IEC 60079-14, Electrical apparatus for explosive gas atmospheres – Part 14: Electrical
installations in hazardous areas (other than mines)
IEC 60079-15, Electrical apparatus for explosive gas atmospheres – Part 15: Construction,
test and marking of type of protection "n" electrical apparatus
IEC 60079-19, Explosive atmospheres – Part 19:Equipment repair, overhaul and reclamation
IEC 60364-6, Low-voltage electrical installations – Part 6: Verification
IEC 61241 (all parts), Combustible dust
IEC 61241-1, Electrical apparatus for use in the presence of combustible dust – Part
1:Protection by enclosures “tD”
IEC 61241-4, Electrical apparatus for use in the presence of combustible dust – Part 4: Type
of protection “pD”
IEC 61241-10, Electrical apparatus for use in the presence of combustible dust – Part 10:
Classification of areas where combustible dusts are or may be present
IEC 61241-11, Electrical apparatus for use in the presence of combustible dust – Part 11:
Protection by intrinsic safety “iD”
IEC 61241-14:2004, Electrical apparatus for use in the presence of combustible dust –
Part 14: Selection and installation
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 60079-0 and the
following apply.
NOTE Additional definitions applicable to explosive atmospheres can be found in Chapter 426 of the International
Electrotechnical Vocabulary (IEV) IEC 60050 (426).

3.1
close inspection
inspection which encompasses those aspects covered by a visual inspection and, in addition,
identifies those defects, such as loose bolts, which will be apparent only by the use of access
equipment, for example steps, (where necessary), and tools
NOTE Close inspections do not normally require the enclosure to be opened, or the equipment to be de-
energized.
3.2
continuous supervision
frequent attendance, inspection, service, care and maintenance of the electrical installation by
skilled personnel who have experience in the specific installation and its environment in order
to maintain the explosion protection features of the installation in satisfactory condition
3.3
detailed inspection
inspection which encompasses those aspects covered by a close inspection and, in addition,
identifies those defects, such as loose terminations, which will only be apparent by opening
the enclosure, and/or using, where necessary, tools and test equipment

60079-17 © IEC:2007 – 9 –
3.4
hazardous area
area in which an explosive atmosphere is present, or may be expected to be present, in
quantities such as to require special precautions for the construction, installation and use of
equipment
NOTE For the purposes of this standard, an area is a three-dimensional region or space.
3.5
initial inspection
inspection of all electrical equipment, systems and installations before they are brought into
service
3.6
inspection
action comprising careful scrutiny of an item carried out either without dismantling, or with the
addition of partial dismantling as required, supplemented by means such as measurement, in
order to arrive at a reliable conclusion as to the condition of an item
3.7
maintenance
combination of any actions carried out to retain an item in, or restore it to, conditions in which
it is able to meet the requirements of the relevant specification and perform its required
functions
3.8
non-hazardous area
area in which an explosive atmosphere is not expected to be present in quantities such as to
require special precautions for the construction, installation and use of equipment
3.9
periodic inspection
inspection of all electrical equipment, systems and installations carried out on a routine basis
3.10
sample inspection
inspection of a proportion of the electrical equipment, systems and installations
3.11
skilled personnel
persons whose training has included instruction on the various types of protection and
installation practices, the requirements of this standard, the relevant national
regulations/company rules applicable to the installation and on the general principles of area
classification
3.12
technical person with executive function
person providing technical management of the skilled personnel, having adequate knowledge
in the field of explosion protection, having familiarity with the local conditions, having
familiarity with the installation and who has overall responsibility and control of the inspection
systems for the electrical equipment within hazardous areas
3.13
visual inspection
inspection which identifies, without the use of access equipment or tools, those defects, such
as missing bolts, which will be apparent to the eye

– 10 – 60079-17 © IEC:2007
4 General requirements
4.1 Documentation
For the purposes of inspection and maintenance, up-to-date documentation of the following
items shall be available:
a) zone classification of areas and, if included, the equipment protection level (EPL) required
for each location (see IEC 60079-10 and IEC 61241-10),
b) for gases: equipment group (IIA, IIB or IIC) and temperature class requirements,
c) for dusts: equipment group (IIIA, IIIB or IIIC) and maximum surface temperature
requirements,
d) equipment characteristics e.g. temperature ratings, type of protection, IP rating, corrosion
resistance,
e) records sufficient to enable the explosion protected equipment to be maintained in
accordance with its type of protection (see IEC 60079-14 and IEC 61241-14), (for example
list and location of equipment, spares, certificates, technical information),
f) copies of previous inspection records.
Requirements for other documentation that may be necessary are provided in IEC 60079-14,
IEC 60079-19 and IEC 61241-14.
4.2 Qualification of personnel
The inspection and maintenance of installations shall be carried out only by experienced
personnel, whose training has included instruction on the various types of protection and
installation practices, the requirements of this standard, the relevant national
regulations/company rules applicable to the installation and on the general principles of area
classification (see Annex B). Appropriate continuing education or training shall be undertaken
by personnel on a regular basis. Evidence of the relevant experience and training claimed
shall be available.
4.3 Inspections
4.3.1 General
Before plant or equipment is brought into service, it shall be given an initial inspection.
To ensure that the installations are maintained in a satisfactory condition for continued use
within a hazardous area, either
a) regular periodic inspections, or
b) continuous supervision by skilled personnel,
and, where necessary, maintenance shall be carried out.
NOTE 1 In the case of dusts, fibres or flyings, housekeeping may influence the inspection and maintenance
requirements.
Following any adjustment, maintenance, repair, reclamation, modification or replacement, the
equipment or relevant parts of equipment concerned shall be inspected in accordance with
the relevant items of the detailed column of Tables 1, 2, 3 and 4.
Where the certification plate or markings on explosion protected equipment is missing or
illegible, alternative methods may be used to determine traceability to the certification details
of the specific equipment. The method used could include: additional identification labels
which incorporate unique tag numbers, serial numbers or reference to the installation

60079-17 © IEC:2007 – 11 –
databases. The method of attaching or fixing the labelling shall not reduce the integrity of the
equipment.
The inventory and identification tagging method used for managing explosion protected
equipment shall be capable of tracking the replacement of equipment with replacement or
repaired equipment, which may have different certification markings and details to the original
equipment.
If at any time there is a change in the area classification or the Equipment Protection Level
requirements or if any equipment is moved from one location to another, a check shall be
made to ensure that the type of protection and surface temperature, where appropriate, are
suitable for the revised conditions.
If plant or equipment is dismantled during the course of an inspection, precautions shall be
taken during reassembly to ensure that the integrity of the type of protection is not impaired,
which includes removing any residual dust and replacing gaskets correctly.
NOTE 2 The major factors effecting the deterioration of equipment include: susceptibility to corrosion, exposure to
chemicals or solvents, likelihood of accumulation of dust or dirt, likelihood of water ingress, exposure to excessive
ambient temperature, risk of mechanical damage, exposure to undue vibration. Other service factors include:
training and experience of personnel, likelihood of unauthorized modifications or adjustments and likelihood of
inappropriate maintenance, for example that which is not in accordance with the manufacturer's recommendation.
4.3.2 Grades of inspection
The grade of inspection may be visual, close or detailed. Tables 1, 2, 3 and 4, or modified
tables in accordance with 5.7, as appropriate, detail the specific checks required for these
three grades of inspection.
Visual and close inspections can be performed with the equipment energized. Detailed
inspections will generally require the equipment to be isolated.
The grade of inspection selected for equipment using more than one type of protection (e.g.
Ex “ed” equipment) shall be a combination of the relevant columns from the Tables in
Annex A.
4.3.3 Types of inspection
a) Initial inspections are used to check that the selected type of protection and its installation
are appropriate. They are to be detailed inspections in accordance with Tables 1, 2, 3 and
4, or modified tables in accordance with 5.7, as appropriate.
NOTE 1 A full initial inspection is not required if an equivalent inspection has been performed by the
manufacturer, and it is unlikely that the installation process will have affected those items inspected by the
manufacturer. For example, an initial detailed inspection of internal flamepaths of a flameproof motor or the
internal joints of an Ex tD motor is not required; however, the terminal housing cover, which would have been
removed to facilitate connection of the field wiring, should be inspected after as part of the installation process.
b) Periodic inspections may be visual or close in accordance with Tables 1, 2, 3 and 4, or
modified tables in accordance with 5.7, as appropriate.
A visual or close periodic inspection may lead to the need for a further detailed inspection.
c) Sample inspections may be visual, close or detailed. The size and composition of all
samples shall be determined with regard to the purpose of the inspection.
NOTE 2 Sample inspection should not be expected to reveal faults of a random nature, such as loose
connections, but should be used to monitor the effects of environmental conditions, vibration, inherent design
weakness, etc.
d) Continuous supervision utilizing the visual or close inspections of Tables 1, 2, 3 and 4, or
modified tables in accordance with 5.7, as appropriate, shall be in accordance with 4.5.
Where the installation falls outside the capability for continuous supervision it shall be
subject to periodic inspection.

– 12 – 60079-17 © IEC:2007
The results of all initial, periodic and sample inspections shall be recorded and retained. The
recording requirements for continuous supervision by skilled personnel are detailed in 4.5.5.
4.4 Periodic inspections
4.4.1 Personnel
Regular periodic inspection requires personnel who:
a) have a knowledge of area classification/EPL and sufficient technical knowledge to
understand its implications for the location under consideration;
b) have technical knowledge and understanding of the theoretical and practical requirements
for electrical equipment and installations used in those hazardous areas;
c) understand the requirements of visual, close and detailed inspections as they relate to the
installed equipment and installations.
NOTE 1 Competencies and training may be identified in relevant national training and assessment frameworks.
Such personnel will need to be sufficiently independent of the demands of the maintenance
activities, for example, so as not to prejudice their ability to reliably report the findings of the
inspection.
NOTE 2 It is not a requirement that such personnel are members of an external independent organisation.
4.4.2 Fixed installations
To predict accurately an appropriate periodic inspection interval is a complex issue. The
grade of inspection and the interval between periodic inspections shall be determined taking
account of the type of equipment, manufacturer's guidance, if any, the factors governing its
deterioration (see Note 2 to 4.3.1), the area classification and/or the EPL requirements and
the results of previous inspections. Where inspection grades and intervals have been
established for similar equipment, plants and environments, this experience shall be used in
determining the inspection strategy.
The interval between periodic inspections shall not exceed three years without seeking expert
advice.
NOTE 1 Intervals between periodic inspections exceeding three years should be based on an assessment
including relevant information.
Once an interval has been fixed, the installation shall be subjected to additional interim
sample inspections to support or modify the proposed interval. Similarly, the grade of
inspection will need to be determined, and here again sample inspection can be used to
support or modify the proposed inspection grade. Ongoing review of the results of inspections
will be required to justify the interval between, and grade of, inspections.
A typical inspection procedure is shown diagrammatically in Annex A.
NOTE 2 When large numbers of similar items such as luminaires, junction boxes, etc. are installed in a similar
environment, it may be feasible to carry out periodical inspections on a sample basis provided that the number of
samples in addition to the inspection frequency is subjected to review. It is, however recommended that all items
be subjected at least to ‘visual inspection’.
4.4.3 Moveable equipment
Movable electrical equipment (hand-held, portable, and transportable) is particularly prone to
damage or misuse and therefore the interval between periodic inspections may need to be
reduced. Movable electrical equipment shall be submitted to a close inspection at least every
12 months. Enclosures which are frequently opened (such as battery housings) shall be given
a detailed inspection at least every 6 months. In addition, the equipment shall be visually

checked by the user, before use, to ensure that the equipment is not obviously damaged.

60079-17 © IEC:2007 – 13 –
4.5 Continuous supervision by skilled personnel
4.5.1 Concept
Where an installation is visited on a regular basis, in the normal course of work, by skilled
personnel who, in addition to satisfying the requirements of 4.4.1 a), b) and c), are
a) aware of the process and environmental implications on the deterioration of the specific
equipment in the installation, and
b) required to carry out visual and/or close inspections as part of their normal work schedule
as well as detailed inspections as part of any replacement, or adjustment in accordance
with 4.3.1,
then it may be possible to dispense with regular periodic inspection and utilize the frequent
presence of the skilled personnel to ensure the on-going integrity of the equipment.
The use of continuous supervision by skilled personnel does not remove the requirement for
initial and sample inspections.
Continuous supervision is not practicable for electrical equipment for which this kind of
attendance cannot be provided (e.g. in the case of movable equipment). See also 4.5.4.
4.5.2 Objectives
The objective of continuous supervision is to enable the early detection of arising faults and
their subsequent repair. It makes use of existing skilled personnel who are in attendance at
the installation in the course of their normal work (e.g. erection work, alterations, inspections,
maintenance work, checking for faults, cleaning work, control operations, switching
operations, making terminal connections and disconnections, setting and adjustment work,
functional tests, measurements) and who use their skill to detect faults and changes at an
early stage.
4.5.3 Responsibilities
4.5.3.1 Technical persons with executive function
A technical person with executive function shall be identified for each installation and shall
carry out the following tasks:
a) assess the viability of the continuous supervision concept in light of the competence, skills
and availability of personnel and their experience in relation to the particular installation;
b) define the scope of equipment to be considered under continuous supervision taking
account of environmental conditions, frequency of attendance, special knowledge, work
flow and location o
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