EN 61241-17:2005

SLOVENSKI STANDARD
01-december-2005
1DGRPHãþD
SIST EN 50281-1-2:2000
SIST EN 50281-1-2:2000/A1:2002
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Electrical apparatus for use in the presence of combustible dust -- Part 17: Inspection
and maintenance of electrical installations in hazardous areas (other than mines)
Elektrische Betriebsmittel zur Verwendung in Bereichen mit brennbarem Staub -- Teil 17:
Prüfung und Instandhaltung elektrischer Anlagen in explosionsgefährdeten Bereichen
(ausgenommen Grubenbaue)
Matériels électriques pour utilisation en présence de poussières combustibles -- Partie
17: Inspection et maintenance des installations électriques situées en emplacements
dangereux (autres que les mines)
Ta slovenski standard je istoveten z: EN 61241-17:2005
ICS:
29.260.20 (OHNWULþQLDSDUDWL]D Electrical apparatus for
HNVSOR]LYQDR]UDþMD explosive atmospheres
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD EN 61241-17
NORME EUROPÉENNE
EUROPÄISCHE NORM May 2005
ICS 29.260.20 Partly supersedes EN 50281-1-2:1998 + A1:2002

English version
Electrical apparatus for use in the presence of combustible dust
Part 17: Inspection and maintenance of electrical installations
in hazardous areas (other than mines)
(IEC 61241-17:2005)
Matériels électriques pour utilisation  Elektrische Betriebsmittel zur Verwendung
en présence de poussières combustibles in Bereichen mit brennbarem Staub
Partie 17: Inspection et maintenance Teil 17: Prüfung und Instandhaltung
des installations électriques situées elektrischer Anlagen in
en emplacements dangereux explosionsgefährdeten Bereichen
(autres que les mines) (ausgenommen Grubenbaue)
(CEI 61241-17:2005) (IEC 61241-17:2005)

This European Standard was approved by CENELEC on 2005-04-01. 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, Cyprus, Czech
Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden,
Switzerland and 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

© 2005 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.

Ref. No. EN 61241-17:2005 E
Foreword
The text of document 31H/191/FDIS, future edition 1 of IEC 61241-17, prepared by SC 31H,
Apparatus for use in the presence of combustible dust, of IEC TC 31, Electrical apparatus for
explosive atmospheres, was submitted to the IEC-CENELEC parallel vote and was approved by
CENELEC as EN 61241-17 on 2005-04-01.
This European Standard, together with EN 61241-1-14:2004, supersedes EN 50281-1-2:1998 +
corrigendum December 1999 + A1:2002.
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) 2006-01-01
– latest date by which the national standards conflicting
with the EN have to be withdrawn (dow) 2008-04-01
Annex ZA has been added by CENELEC.
__________
Endorsement notice
The text of the International Standard IEC 61241-17:2005 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 60079-0 NOTE Harmonized as EN 60079-0:2004 (not modified).
IEC 60079-17 NOTE Harmonized as EN 60079-17:2003 (not modified).
IEC 60204-1 NOTE Harmonized as EN 60204-1:1997 (not modified).
IEC 61241-1 NOTE Harmonized as EN 61241-1:2004 (not modified).
IEC 61241-18 NOTE Harmonized as EN 61241-18:2004 (not modified).
__________
- 3 - EN 61241-17:2005
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 Where an international publication has been modified by common modifications, indicated by (mod), the relevant
EN/HD applies.
Publication Year Title EN/HD Year
IEC 60079-14 2002 Electrical apparatus for explosive gas EN 60079-14 2003
atmospheres
Part 14: Electrical installations in
hazardous areas (other than mines)

1)
IEC 60364-6-61 - Electrical installations of buildings - -
Part 6-61: Verification - Initial verification

1)
IEC 61241-4 - Electrical apparatus for use in the - -
presence of combustible dust
Part 4: Type of protection 'pD'

1)
2)
IEC 61241-10 - Part 10: Classification of areas where EN 61241-10 2004
combustible dusts are or may be present

3)
IEC 61241-11 - Part 11: Intrinsically safe apparatus 'iD' - -

IEC 61241-14 2004 Part 14: Selection and installation EN 61241-14 2004

1)
Undated reference.
2)
Valid edition at date of issue.
3)
At draft stage.
NORME CEI
INTERNATIONALE IEC
61241-17
INTERNATIONAL
Première édition
STANDARD
First edition
2005-01
Matériels électriques pour utilisation
en présence de poussières combustibles –
Partie 17:
Inspection et maintenance des installations
électriques situées en emplacements dangereux
(autres que les mines)
Electrical apparatus for use in the presence of
combustible dust –
Part 17:
Inspection and maintenance of electrical
installations in hazardous areas (other than mines)

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For price, see current catalogue

61241-17  IEC:2005 – 3 –
CONTENTS
FOREWORD.5
INTRODUCTION.11

1 Scope .13
2 Normative references .13
3 Terms and definitions .15
4 General requirements .19
4.1 Documentation .19
4.2 Qualification of personnel .19
4.3 Inspections.19
4.4 Regular periodic inspections .23
4.5 Continuous supervision by skilled persons .23
4.6 Maintenance requirements.27
4.7 Environmental conditions .29
4.8 Isolation of apparatus .31
4.9 Earthing and equipotential bonding .35
4.10 Conditions of use.35
4.11 Movable apparatus and its connections.35
4.12 Inspection schedules (Tables 1 to 3) .35
5 Additional inspection schedule requirements .37
5.1 Type of protection "iD" – Intrinsic safety (see Table 2 and IEC 61241-11) .37
5.2 Type of protection "pD" – Pressurized enclosure (see Table 3 and
IEC 61241-4).43
5.3 Apparatus used in zone 22 .43
5.4 Types of protection “mD” (encapsulation) .43
6 Typical inspection schedules .45

Annex A (informative) Typical inspection procedure for periodic inspections.51

Bibliography .52

Table 1 – Inspection schedule for Ex "tD" installations .45
Table 2 – Inspection schedule for Ex "iD" installations .47
Table 3 – Inspection schedule for Ex "pD" installations .49

61241-17  IEC:2005 – 5 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
___________
ELECTRICAL APPARATUS FOR USE
IN THE PRESENCE OF COMBUSTIBLE DUST –

Part 17: Inspection and maintenance of electrical installations
in hazardous areas (other than mines)

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 61241-17 has been prepared by subcommittee 31H: Apparatus for
use in the presence of combustible dust, of IEC technical committee 31: Electrical apparatus
for explosive atmospheres.
The text of this standard is based on the following documents:
FDIS Report on voting
31H/191/FDIS 31H/193/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.

61241-17  IEC:2005 – 7 –
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
IEC 61241 consists of the following parts under the general title Electrical apparatus for use in
the presence of combustible dust:
Part 0: General requirements
Part 1: Protection by enclosures ‘tD’
Part 4: Type of protection ‘pD’
Part 10: Classification of areas where combustible dusts are or may be present
Part 11: Protection by intrinsic safety ‘iD’
Part 14: Selection and installation
Part 17: Inspection and maintenance of electrical installations in hazardous areas (other
than mines)
Part 18: Protection by encapsulation ‘mD’
Part 20: Test methods
Part 20-1: Methods for determining the minimum ignition temperatures of dust
Part 20-2: Method for determining the electrical resistivity of dust in layers
Part 20-3: Method for determining minimum ignition energy of dust/air mixtures
NOTE All references in this standard to the IEC 61241 series follows the proposed re-numbering of the dust
standards agreed by SC31H and TC31. It may be necessary to alter these numbers if the relevant standards are
not yet published.
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.
___________
To be published.
Under consideration.
61241-17  IEC:2005 – 9 –
REFERENCE TABLE
Anticipated
New number
Existing standard Subject date of
assigned
change
IEC 61241-0 General requirements 2004
IEC 61241-1-1
IEC 61241-1 Protection by enclosure 2004
IEC 61241-1-2 IEC 61241-14 Selection and installation 2004
IEC 61241-2-1 IEC 61241-20-1 Test methods 2005
IEC 61241-2-2 IEC 61241-20-2 Test methods 2005
IEC 61241-2-3 IEC 61241-20-3 Test methods 2005
IEC 61241-3 IEC 61241-10 Classification 2004
IEC 61241-4 IEC 61241-2 Protection by pressurization 2005
IEC 61241-11 Protection by intrinsic safety 2005
IEC 61241-17 Inspection and maintenance 2004
IEC 61241-18 Protection by encapsulation 2004
IEC 61241-19 Repair and overhaul 2006

61241-17  IEC:2005 – 11 –
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.

61241-17  IEC:2005 – 13 –
ELECTRICAL APPARATUS FOR USE
IN THE PRESENCE OF COMBUSTIBLE DUST –

Part 17: Inspection and maintenance of electrical installations
in hazardous areas (other than mines)

1 Scope
This part of IEC 61241 is intended to be applied by users and covers factors directly related
to the inspection and maintenance of electrical installations within hazardous areas only. It
does not include conventional requirements for electrical installations, nor the testing and
certification of electrical apparatus. This standard supplements the requirements laid down in
IEC 60364-6-61.
NOTE The text is based on IEC 60079-17.
This standard assumes effective housekeeping based on a system of cleaning for the plant.
The principles of this standard can also be followed when combustible fibres or flyings may
cause a hazard.
This standard is intended to be applied where there can be a risk due to the presence of
explosive dust/air mixtures 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, or to
• 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 60079-14:2002, Electrical apparatus for explosive gas atmospheres – Part 14: Electrical
installations in hazardous areas (other than mines)
IEC 60364-6-61: Electrical installations of buildings – Part 6-61: Verification – Initial
verification
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

61241-17  IEC:2005 – 15 –
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 following terms and definitions apply.
3.1
explosive atmosphere
mixture with air, under atmospheric conditions, of flammable substances in the form of gas,
vapour, mist or dust, in which after ignition, combustion spreads throughout the unconsumed
mixture
3.2
explosive dust atmosphere
mixture with air, under atmospheric conditions, of flammable substances in the form of dust,
fibres or flyings in which, after ignition, combustion spreads throughout the unconsumed
mixture
3.3
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
apparatus
NOTE For the purposes of this standard, an area is a three-dimensional region or space.
3.4
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 apparatus
3.5
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
3.6
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
3.6.1
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
___________
To be published.
61241-17  IEC:2005 – 17 –
3.6.2
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.
3.6.3
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
3.6.4
initial inspection
inspection of all electrical apparatus, systems and installations before they are brought into
service
3.6.5
periodic inspection
inspection of all electrical apparatus, systems and installations carried out on a routine basis
3.6.6
sample inspection
inspection of a proportion of the electrical apparatus, systems and installations
3.7
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
3.8
skilled personnel
people who meet the requirements for the qualification of personnel in accordance with 4.2
3.9
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
3.10
associated apparatus
electrical apparatus in which the circuits, or parts of circuits, are not all necessarily
intrinsically safe but which contains circuits that can affect the safety of the intrinsically safe
circuits associated with it
NOTE The associated apparatus is normally the interface between an intrinsically safe circuit and a non-
intrinsically safe circuit and is frequently located in the non-hazardous area. The associated apparatus may be, for
example, shunt diode safety barriers or galvanic isolators.

61241-17  IEC:2005 – 19 –
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) the classification of hazardous areas (see IEC 61241-10) including material characteristics
as electrical resistivity, the minimum ignition temperature of the combustible dust cloud,
minimum ignition temperature of the combustible dust layer and minimum ignition energy
of the combustible dust cloud;
b) apparatus characteristics e.g. temperature ratings, type of protection, IP rating, corrosion
resistance;
c) records sufficient to enable the explosion protected equipment to be maintained in
accordance with its type of protection (see IEC 61241-14) (for example list and location of
apparatus, spares, technical information).
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 relevant rules and regulations and on the general principles of area
classification. 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 apparatus 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 Effective housekeeping is assumed.
Following any replacement, repair, modification or adjustment, the items concerned shall be
inspected in accordance with the relevant items of the detailed column of Tables 1, 2 and 3.
If at any time there is a change in the area classification or if any apparatus 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 apparatus 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.

61241-17  IEC:2005 – 21 –
NOTE 2 The major factors effecting the deterioration of apparatus 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, 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 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 detail inspection graded as shown in Tables 1, 2 and 3, 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 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 installation.
b) Periodic inspections may be visual or close as shown in Tables 1, 2 and 3, as appropriate.
A visual or close periodic inspection may lead to the need for a further detailed inspection.
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 zone of use and the results of
previous inspections. Where inspection grades and intervals have been established for
similar apparatus, 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.
Movable electrical apparatus (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 apparatus 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. In addition, the apparatus shall be visually checked by the
user, before use, to ensure that the apparatus is not obviously damaged.
c) Sample inspection 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 and 3, 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.
The results of all initial, periodic and sample inspections shall be recorded. The recording
requirements for continuous supervision by skilled personnel are detailed in 4.5.5.
4.3.3 Grades of inspection
The grade of inspection can be visual, close or detailed. Tables 1, 2 and 3 detail the specific
checks required for these three grades of inspection.
Visual and close inspections can be performed with the apparatus energized. Detailed
inspections will generally require the apparatus to be isolated.

61241-17  IEC:2005 – 23 –
4.4 Regular periodic inspections
Regular periodic inspection requires personnel who
a) have a knowledge of area classification 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 apparatus used in those hazardous areas;
c) understand the requirements of visual, close and detailed inspections as they relate to the
installed apparatus.
Such personnel will need to be sufficiently independent of the demands of the maintenance
activities so as not to prejudice their ability to reliably report the findings of the inspection.
NOTE It is not a requirement that such personnel are members of an external independent organisation.
To predict accurately an appropriate periodic inspection interval may not be easy, but it shall
be fixed taking into account the expected deterioration (see 4.3.1).
Once an interval has been fixed, the installation shall be subjected to 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. A regular 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.
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, strongly recommended that all items be subjected at least to visual
inspection.
4.5 Continuous supervision by skilled persons
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 a), b) and c), are
a) aware of the process and environmental implications on the deterioration of the specific
apparatus 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, repair, modification or
adjustment in accordance with 4.3.1,
then it may be possible to dispense with regular periodic inspection and utilize the more
frequent presence of the skilled personnel to ensure the on-going integrity of the apparatus.
NOTE 1 The use of continuous supervision by skilled personnel does not remove the requirement for initial and
sample inspections.
NOTE 2 Continuous supervision is not practicable for electrical apparatus for which this kind of attendance cannot
be provided (e.g. in the case of movable apparatus). See also 4.5.4.

61241-17  IEC:2005 – 25 –
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 of equipment;
c) determine the frequency of inspection, the grade of inspection and the content of reporting
such as to enable meaningful analysis of apparatus performance;
d) ensure that the documentation referred to in 4.1 and 4.5.5 is made available;
e) ensure that skilled personnel are familiar with
i) the concept of continuous supervision together with the needs for any reporting or
analysis function;
ii) the installation they attend;
iii) the inventory of explosion protected apparatus;
f) arrange for verification that
i) process of continuous supervision is being adhered to;
ii) skilled personnel are being given adequate time to carry out their inspections;
iii) skilled personnel are receiving appropriate training and refresher training;
iv) documentation is being completed correctly;
v) there is adequate technical support readily available to the skilled personnel;
vi) the state of the electrical installation is known.
4.5.3.2 Skilled personnel
The skilled personnel shall be familiar with the concept of continuous supervision together
with the needs for any reporting or analysis functions which may comprise the method of
continuous supervision applicable to the specific installation.
In undertaking continuous supervision of plant and equipment the skilled personnel shall take
account of the conditions of the installation and any changes which may occur.

61241-17  IEC:2005 – 27 –
4.5.4 Frequency of inspection
The frequency of the attendance and the inspections which support continuous supervision
shall be determined having regard to the specific plant environment in relation to expected
deterioration of the apparatus (see 4.3.1), use and experience.
NOTE 1 Unless experience indicates to the contrary, it may be considered that if a part of the plant having a
significant inventory of explosion protected systems is not visited more frequently than once per week, then it
would be inappropriate to include it as part of the continuous supervision concept.
Where the skilled personnel have noted a condition change of the environment (e.g. invasion
of solvent or increased vibration) those items of explosion protected equipment which could
be sensitive to the change should be checked on a more frequent basis.
NOTE 2 It also follows that the skilled personnel will be able to inspect less frequently those items of equipment
that experience shows are not susceptible to change.
4.5.5 Documents
Documentation of the installation shall provide sufficient information to
a) provide a history of maintenance activities with the reason for such activities, and
b) verify the effectiveness of the continuous supervision approach.
Records shall be kept of defects found and remedial action taken.
NOTE 1 The documentation may be part of normal maintenance documentation; however, the interrogation
arrangements for the system must then be suitable to achieve the above-mentioned concepts.
NOTE 2 The evidence that the skilled personnel are aware of the needs of the continuous supervision concept
could be in the form of training programmes. Other evidence of this form of education is also possible.
4.5.6 Training
In addition to the requirements of 4.2, skilled personnel shall be provided with sufficient
training to enable familiarity with the installation which they attend. This training shall include
any plant, apparatus, operational or environmental conditions which relate to their
understanding of the needs of the explosion protection of apparatus. Where any alterations or
changes to the process or installation are effected this information shall be provided to the
skilled personnel in a manner which supports their function as part of the continuous
supervision process.
Where necessary, training in the concepts of continuous supervision shall be provided
together with refresher or reinforcement seminars.
The knowledge requirements of the technical person with executive function shall include a
full understanding of the provisions of IEC 61241-10 and IEC 61241-14 in relation to area
classification and selection and installation of apparatus.
4.6 Maintenance requirements
4.6.1 Remedial measures and alterations to apparatus
The general condition of all apparatus shall be noted as required in 4.3, and appropriate
remedial measures shall be taken where necessary. Care shall be taken, however, to
maintain the integrity of the type of protection provided for the apparatus; this may require
consultation with the manufacturer.

61241-17  IEC:2005 – 29 –
Replacement parts shall be in accordance with the safety documentation. Alterations to
apparatus shall not be carried out without appropriate authorization where they adversely
affect the safety of the apparatus as stated in the safety documentation.
NOTE 1 Care should be taken to avoid interfering with the means employed by the manufacturer to reduce the
effects of static electricity.
NOTE 2 When replacing lamps in luminaires the correct rating and type should be used, or excessive
temperatures may result.
NOTE 3 The etching, painting or screening of light transmitting parts or the incorrect positioning of the luminaires
may lead to excessive temperatures.
4.6.2 Maintenance of flexible cables
Flexible cables, flexible conduits and their terminations are particularly prone to damage.
They shall be inspected at regular intervals and shall be replaced if found to be damaged or
defective.
4.6.3 Withdrawal from service
If it is necessary for maintenance purposes to withdraw apparatus, etc. from service, the
exposed conductors shall be
a) correctly terminated in an appropriate enclosure,
b) or isolated from all sources of power supply and insulated,
c) or isolated from all sources of power supply and earthed.
If the apparatus is to be permanently withdrawn from service, the associated wiring, which
shall be isolated from all sources of power supply, shall be removed, or, alternatively,
correctly terminated in an appropriate enclosure.
4.6.4 Fastenings and tools
Where special bolts and other fastenings or special tools are required, these items shall be
available and shall be used.
4.7 Environmental conditions
Electrical apparatus in a hazardous area can be adversely affected by the environmental
conditions in which it is used. Some of the key elements to consider are corrosion, ambient
temperature, ultraviolet radiation, ingress of water, accumulation of dust or sand, mechanical
effects and chemical attack.
The corrosion of metal, or the influences of chemicals (particularly solvents) on plastic or
elastomeric components, may affect the type and degree of protections of the apparatus. If
the enclosure or component is severely corroded, the part shall be replaced. Plastic
enclosures may exhibit surface cracking which can affect the integrity of the enclosure.
Metallic enclosures of apparatus shall, where necessary, be treated with an appropriate
protective coating as a precaution against corrosion, the frequency and nature of such
treatment being determined by the environmental conditions.
It shall be verified that the electrical equipment is designed to withstand the highest and
lowest ambient temperatures likely to be encountered.
NOTE If the marking of the explosion protected apparatus does not indicate a range of ambient temperatures, it
should only be used over the range of –20 °C to +40 °C, while if a range is indicated the equipment should only be
used within this range.
61241-17  IEC:2005 – 31 –
All parts of installations should be kept clean and free from accumulations of dust and
deleterious substances of such a nature as could cause excessive rise in temperature.
Care shall be taken to ensure that the weather protection of the apparatus is maintained.
Damaged gaskets shall be replaced.
Anti-condensation devices, such as breathing, draining or heating elements, shall be checked
to ensure correct operation.
If the apparatus is subject to vibration, special care shall be taken to ensure that bolts and
cable entries remain tight.
Care
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