SIST EN 60079-30-1:2007

Explosive atmospheres -- Part 30-1: Electrical resistance trace heating - General and testing requirements

This part of IEC 60079 specifies general and testing requirements for electrical resistance trace heaters for application in explosive gas atmospheres. The standard covers trace heaters that may comprise either factory- or field- (work-site) assembled units, and which may be series heating cables, parallel heating cables or heating pads and heating panels that have been assembled and/or terminated in accordance with the manufacturer's instructions. This standard also includes requirements for termination assemblies and control methods used with trace heating. The hazardous areas referred to by this standard are those defined in IEC 60079-10. Where a requirement of this standard conflicts with a requirement of IEC 60079-0, the requirement of this standard shall take precedence.

Explosionsfähige Atmosphäre -- Teil 30-1: Elektrische Widerstands-Begleitheizungen - Allgemeine Anforderungen und Prüfanforderungen

Atmosphères explosives -- Partie 30-1: Traçage par résistance électrique - Exigences générales et d'essais

La présente partie de la CEI 60079 spécifie les exigences générales et d'essais des résistances électriques de traçage en atmosphères explosives gazeuses. La norme s'applique aux résistances de traçage qui peuvent comprendre les unités assemblées sur site (site d'exploitation) ou en usine et qui peuvent être soit des câbles de traçage en série, soit des câbles de traçage en parallèle, soit des bandes ou des panneaux de traçage qui ont été assemblés et/ou équipés de terminaisons conformément aux instructions du constructeur.

Eksplozivne atmosfere - 30-1. del: Električni uporovni grelni trakovi - Splošne zahteve in zahteve za preskušanje (IEC 60079-30-1:2007)

General Information

• Status: Withdrawn
• Publication Date: 04-Nov-2007
• Withdrawal Date: 05-Jan-2020
• ICS: 29.260.20 - Electrical apparatus for explosive atmospheres
• Technical Committee: EXP - Electrical apparatus for explosive atmospheres
• Current Stage: 9900 - Withdrawal (Adopted Project)
• Start Date: 16-Feb-2018
• Due Date: 11-Mar-2018
• Completion Date: 06-Jan-2020
• Directive: 2014/34/EU - Directive 2014/34/EU Of The European Parliament And Of The Council of 26 February 2014 on the harmonisation of the laws of the Member States relating to equipment and protective systems intended for use in potentially explosive atmospheres (recast)
• Directive: 94/9/EC - Directive 94/9/EC of the European Parliament and the Council of 23 March 1994 on the approximation of the laws of the Member States concerning equipment and protective systems intended for use in potentially explosive atmospheres
• Ref Project: EN 60079-30-1:2007 - Explosive atmospheres - Part 30-1: Electrical resistance trace heating - General and testing requirements

Relations

• Replaces: SIST EN 62086-1:2005 - Electrical apparatus for explosive gas atmospheres - Electrical resistance trace heating -- Part 1: General and testing requirements
• Effective Date: 01-Mar-2010
• Replaced By: SIST EN 60079-30-1:2017 - Explosive atmospheres - Part 30-1: Electrical resistance trace heating - General and testing requirements (IEC/IEEE 60079-30-1:2015 , modified)
• Effective Date: 11-Apr-2017

Standards Content (Sample)

SLOVENSKI STANDARD
SIST EN 60079-30-1:2007
01-december-2007
1DGRPHãþD
SIST EN 62086-1:2005
(NVSOR]LYQHDWPRVIHUHGHO(OHNWULþQLXSRURYQLJUHOQLWUDNRYL6SORãQH
]DKWHYHLQ]DKWHYH]DSUHVNXãDQMH,(&
Explosive atmospheres - Part 30-1: Electrical resistance trace heating - General and
testing requirements
Explosionsfähige Atmosphäre - Teil 30-1: Elektrische Widerstands-Begleitheizungen -
Allgemeine Anforderungen und Prüfanforderungen
Atmospheres explosives - Partie 30-1: Traçage par résistance électrique - Exigences
générales et d'essais
Ta slovenski standard je istoveten z: EN 60079-30-1:2007
ICS:
29.260.20 (OHNWULþQLDSDUDWL]D Electrical apparatus for
HNVSOR]LYQDR]UDþMD explosive atmospheres
SIST EN 60079-30-1:2007 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------

EUROPEAN STANDARD
EN 60079-30-1

NORME EUROPÉENNE
April 2007
EUROPÄISCHE NORM

ICS 29.260.20 Supersedes EN 62086-1:2005


English version


Explosive atmospheres -
Part 30-1: Electrical resistance trace heating -
General and testing requirements
(IEC 60079-30-1:2007)


Atmosphères explosives -  Explosionsfähige Atmosphäre -
Partie 30-1: Traçage Teil 30-1: Elektrische
par résistance électrique - Widerstands-Begleitheizungen -
Exigences générales et d'essais Allgemeine Anforderungen
(CEI 60079-30-1:2007) und Prüfanforderungen
(IEC 60079-30-1:2007)




This European Standard was approved by CENELEC on 2007-03-01. 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 60079-30-1:2007 E

---------------------- Page: 2 ----------------------

EN 60079-30-1:2007 - 2 -
Foreword
The text of document 31/661/FDIS, future edition 1 of IEC 60079-30-1, prepared by IEC TC 31,
Equipment for explosive atmospheres, was submitted to the IEC-CENELEC parallel vote and was
approved by CENELEC as EN 60079-30-1 on 2007-03-01.
This European Standard supersedes EN 62086-1:2005.
The general revisions and updating to produce EN 60079-30-1:2007, with respect to EN 62086-1:2005,
are a result of national comments received.
The main technical differences, apart from the general revision and updating of EN 62086-1:2005, are as
follows:
– the inclusion of thermal safety requirements for the manufacturer’s quality programme;
– the inclusion of a 14 day water resistance test;
– the further harmonization of this standard with several national standards.
This standard is to be used in conjunction with EN 60079-30-2:2007, Explosive atmospheres – Part 30-2:
Electrical resistance trace heating – Application guide for design, installation and maintenance.
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) 2007-12-01
– latest date by which the national standards conflicting
with the EN have to be withdrawn (dow) 2010-03-01
This European Standard has been prepared under a mandate given to CENELEC by the European
Commission and the European Free Trade Association and covers essential requirements of
EC Directive ATEX (94/9/EC). See Annex ZZ.
Annexes ZA and ZZ have been added by CENELEC.
__________
Endorsement notice
The text of the International Standard IEC 60079-30-1:2007 was approved by CENELEC as a European
Standard without any modification.
__________

---------------------- Page: 3 ----------------------

- 3 - EN 60079-30-1:2007
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)
IEC 60050-151 - International Electrotechnical Vocabulary - -
(IEV) -
Part 151: Electrical and magnetic devices


IEC 60079-0 (mod) 2004 Electrical apparatus for explosive gas EN 60079-0 2006
atmospheres -
Part 0: General requirements


2)
IEC 60079-7 2001 Electrical apparatus for explosive gas EN 60079-7 2003
atmospheres -
Part 7: Increased safety "e"


IEC 60079-10 2002 Electrical apparatus for explosive gas EN 60079-10 2003
atmospheres -
Part 10: Classification of hazardous areas


1) 3)
IEC 60079-30-2 - Explosive atmospheres - EN 60079-30-2 2007
Part 30-2: Electrical resistance trace heating -
Application guide for design, installation and
maintenance


1) 3)
IEC 60364-5-55 - Electrical installations of buildings - HD 60364-5-559 2005
(mod) Part 5-55: Selection and erection of electrical
equipment - Other equipment



1)
Undated reference.
2)
EN 60079-7 is superseded by EN 60079-7:2007, which is based on IEC 60079-7:2006.
3)
Valid edition at date of issue.

---------------------- Page: 4 ----------------------

EN 60079-30-1:2007 - 4 -
Annex ZZ
(informative)

Coverage of Essential Requirements of EC Directives

This European Standard has been prepared under a mandate given to CENELEC by the European
Commission and the European Free Trade Association and within its scope the standard covers only the
following relevant essentiel requirements out of those given in Annex II of the EC Directive 94/9/EC

– ER 1.0.1, ER 1.0.2, ER 1.0.4, ER 1.05, 1.06 (partly)
– ER 1.1
– ER 1.2.1 (partly), ER 1.2.2 (partly), ER 1.2.5, ER 1.2.8
– ER 1.3.1 (partly), ER 1.3.3, ER 1.3.4 (partly),
– ER 1.4.1 (partly), ER 1.4.2
– ER 1.6.4
– ER 2.2.1.1 to ER 2.2.1.3
– ER 2.3.1.1, ER 2.3.1.2

Compliance with this standard provides one means of conformity with the specified essential
requirements of the Directive concerned.

WARNING: Other requirements and other EC Directives may be applicable to the products falling within
the scope of this standard.

---------------------- Page: 5 ----------------------

NORME CEI
INTERNATIONALE
IEC



60079-30-1
INTERNATIONAL


Première édition
STANDARD

First edition

2007-01


Atmosphère explosives –
Partie 30-1:
Traçage par résistance électrique –
Exigences générales et d’essais

Explosive atmospheres –
Part 30-1:
Electrical resistance trace heating –
General and testing requirements
© IEC 2007 Droits de reproduction réservés ⎯ Copyright - all rights reserved
Aucune partie de cette publication ne peut être reproduite ni No part of this publication may be reproduced or utilized in any
utilisée sous quelque forme que ce soit et par aucun procédé, form or by any means, electronic or mechanical, including
électronique ou mécanique, y compris la photocopie et les photocopying and microfilm, without permission in writing from
microfilms, sans l'accord écrit de l'éditeur. the publisher.
International Electrotechnical Commission, 3, rue de Varembé, PO Box 131, CH-1211 Geneva 20, Switzerland
Telephone: [phone] Telefax: [phone] E-mail: [e-mail] Web: www.iec.ch
CODE PRIX
U
PRICE CODE
Commission Electrotechnique Internationale
International Electrotechnical Commission
МеждународнаяЭлектротехническаяКомиссия
Pour prix, voir catalogue en vigueur
For price, see current catalogue

---------------------- Page: 6 ----------------------

60079-30-1 © IEC:2007 – 3 –
CONTENTS
FOREWORD.5
INTRODUCTION.9

1 Scope.11
2 Normative references .11
3 Terms and definitions.11
4 General requirements .21
4.1 General .21
4.2 Terminations and connections .23
4.3 Circuit protection requirements for branch circuits .23
4.4 Control and temperature requirements .23
5 Testing .25
5.1 Type tests .25
5.2 Routine tests .51
6 Marking .51
6.1 Product markings for trace heaters.51
6.2 Markings for field-assembled components .53
6.3 Installation instructions.53

Figure 1 – Flammability test.29
Figure 2 – Impact test .31
Figure 3 – Cold bend test – Type test .35
Figure 4 – Integral components resistance to water test.37
Figure 5 – Verification of rated output .41
Figure 6 – Verification of sheath temperature using system approach .47
Figure 7 – Maximum sheath temperature using the product classification approach .49

Table 1 – Test voltages for the dielectric test.27

---------------------- Page: 7 ----------------------

60079-30-1 © IEC:2007 – 5 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________

EXPLOSIVE ATMOSPHERES –

Part 30-1: Electrical resistance trace heating –
General and testing requirements


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 60079-30-1 has been prepared by IEC technical committee 31:
Equipment for explosive atmospheres.
This edition cancels and replaces the first edition of IEC 62086-1 published in 2001 and
constitutes a technical revision.
The general revisions and updating to produce the first edition of IEC 60079-30-1, with
respect to former edition of IEC 62086-1, are a result of national comments received.

---------------------- Page: 8 ----------------------

60079-30-1 © IEC:2007 – 7 –
The main technical differences, apart from the general revision and updating of former edition
of IEC 62086-1, are as follows:
a) the inclusion of thermal safety requirements for the manufacturer’s quality programme;
b) the inclusion of a 14 day water resistance test;
c) the further harmonization of this edition with several national standards.
This Part 30-1 is intended to be used in conjunction with the first edition of IEC 60079-30-2:
2006, Explosive atmospheres – Part 30-2: Electrical resistance trace heating – Application
guide for design, installation and maintenance.
The text of this standard is based on the following documents:
FDIS Report on voting
31/661/FDIS 31/671/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.
The list of all parts of 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.

---------------------- Page: 9 ----------------------

60079-30-1 © IEC:2007 – 9 –
INTRODUCTION
This part of IEC 60079 is intended to provide a comprehensive overview of the essential
requirements and testing appropriate to electric surface heating equipment used in explosive
gas atmospheres. The requirements of this standard are considered to be the minimum
requirements for zone 1 or zone 2. While some of this work already exists in national
standards or international standards, this standard has collated much of this existing work and
considerably added to it.

---------------------- Page: 10 ----------------------

60079-30-1 © IEC:2007 – 11 –
EXPLOSIVE ATMOSPHERES –

Part 30-1: Electrical resistance trace heating –
General and testing requirements



1 Scope
This part of IEC 60079 specifies general and testing requirements for electrical resistance
trace heaters for application in explosive gas atmospheres. The standard covers trace heaters
that may comprise either factory- or field- (work-site) assembled units, and which may be
series heating cables, parallel heating cables or heating pads and heating panels that have
been assembled and/or terminated in accordance with the manufacturer’s instructions.
This standard also includes requirements for termination assemblies and control methods
used with trace heating. The hazardous areas referred to by this standard are those defined in
IEC 60079-10.
Where a requirement of this standard conflicts with a requirement of IEC 60079-0, the
requirement of this standard shall take precedence.
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(151), International Electrotechnical Vocabulary (IEV) – Part 151: Electrical and
magnetic devices
IEC 60079-0:2004, Electrical apparatus for explosive gas atmospheres – Part 0: General
requirements
IEC 60079-7:2001, Electrical apparatus for explosive gas atmospheres – Part 7: Increased
safety ‘e’
IEC 60079-10:2002, Electrical apparatus for explosive gas atmospheres – Part 10:
Classification of hazardous areas
IEC 60079-30-2, Explosive atmospheres – Part 30-2: Electrical resistance trace heating –
Application guide for design, installation and maintenance
IEC 60364-5-55, Electrical installations of buildings – Part 5-55: Selection and erection of
electrical equipment – Other equipment
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 60079-0 and
IEC 60079-7 as well as the following apply.

---------------------- Page: 11 ----------------------

60079-30-1 © IEC:2007 – 13 –
1
NOTE Additional definitions applicable to explosive atmospheres can be found in IEC 60050-426 .
3.1
ambient temperature
temperature surrounding the object under consideration. Where electrical trace heaters are
enclosed in thermal insulation, the ambient temperature is the temperature exterior to such
thermal insulation
3.2
branch circuit
that portion of the wiring installation between the overcurrent device protecting the circuit and
the trace heater unit(s)
3.3
connections (terminations)
3.3.1
cold lead
electrically insulated conductor or conductors used to connect a trace heater to the branch
circuit and designed so that it does not produce significant heat
3.3.2
end termination
termination, which may be heat producing, applied to a trace heater at the end opposite that
where the power is supplied
3.3.3
power termination
termination applied to the end of a trace heater at which the power is supplied
3.4
tee
electrical connection of trace heaters, in series or in parallel, to accommodate a tee or branch
3.5
dead leg
segment of process piping segregated from the normal flow pattern for the purpose of
providing a heat-loss reference
3.6
design loading
minimum power that will meet the design requirements, in the worst conditions, after voltage
and resistance tolerances and appropriate safety factors have been considered
3.7
factory-fabricated
trace heaters, including the necessary terminations and connections, assembled into units or
sets
___________
1
IEC 60050(426), International Electrotechnical Vocabulary (IEV) – Chapter 426: Electrical apparatus for
explosive atmospheres

---------------------- Page: 12 ----------------------

60079-30-1 © IEC:2007 – 15 –
3.8
field-assembled
trace heaters supplied in bulk with terminating components to be assembled at the work site
3.9
heat loss
energy flow from a pipe, vessel or equipment to its surroundings
3.10
heat sink
part that conducts and dissipates heat away from a workpiece
NOTE Typical heat sinks are pipe shoes, pipe supports and items of large mass such as valve actuators or pump
bodies.
3.11
heat-transfer aids
thermally conductive materials, such as metallic foils or heat-transfer compounds used to
increase the heat-transfer efficiency from trace heaters to the workpiece
3.12
heating pad
trace heater comprising series- or parallel-connected elements having sufficient flexibility to
conform to the shape of the surface to be heated
3.13
heating panel
non-flexible trace heater comprising series- or parallel-connected elements fabricated to
conform to the general shape of the surface to be heated
3.14
high-limit temperature
maximum allowable temperature of the system, including piping, fluid and heating system
3.15
maximum withstand temperature
maximum operating or exposure temperature that will not adversely effect the thermal stability
of the trace heater and its component parts
3.16
metallic covering
metal sheath or braid used to provide physical protection for a trace heater, and may provide
an electrical earth path
3.17
minimum ambient temperature
lowest ambient temperature specified at which heat-loss calculations are based and the trace
heating is operable and performs according to the specified requirements
3.18
operating voltage
actual voltage applied to the trace heater when in service

---------------------- Page: 13 ----------------------

60079-30-1 © IEC:2007 – 17 –
3.19
overjacket
continuous layer of insulating material applied outside the metallic sheath, screen or
armouring to protect against corrosion
3.20
parallel trace heater(s)
heating elements that are electrically connected in parallel, either continuously or in zones, so
that the watt density per lineal length is maintained, irrespective of any change in length for
the continuous type or for any number of discrete zones
3.21
power density
power output in watts per linear metre for trace heater cables and cable units, and in watts
per square metre for trace heater pads and panels and trace heater pad and panel units
3.22
rated output
total power or power per unit length or unit surface area of a trace heater, at rated voltage,
temperature and length, which is normally expressed in watts, watts per metre or watts per
square metre
3.23
rated voltage
voltage to which operating and performance characteristics of trace heaters are referred
3.24
routine test
conformity test made on each individual item during or after manufacture
[IEV 151-16-17]
3.25
series trace heater(s)
heating elements electrically connected in series with a single current path and with a specific
resistance at a given temperature for a given length
3.26
sheath
uniform and continuous metallic or non-metallic outer covering enclosing the trace heater
used to provide protection against influence from the surroundings (corrosion, moisture etc.).
See overjacket, 3.19
3.27
sheath temperature
temperature of the outermost continuous covering that may be exposed to the surrounding
atmosphere
3.28
stabilized design
concept where the temperature of the trace heater will, by design and use, stabilize below the
high-limit temperature, under the most unfavourable conditions, without the need for a
protective system to limit the temperature

---------------------- Page: 14 ----------------------

60079-30-1 © IEC:2007 – 19 –
3.29
start-up current
the current response of a trace heater following energization
3.30
system documentation
information provided by the supplier to allow satisfactory understanding, installation and safe
use of the trace heating system
3.31
temperature alarm device
serves to activate an alarm when the sensor temperature is outside the specified temperature
range
3.32
temperature control device
serves to maintain the temperature within a specified temperature range
3.33
temperature controller
device or combination of devices incorporating a means of sensing temperature and of
controlling the power to the trace heater
3.34
temperature limiting device
serves to switch off power to the trace heater to prevent the high-limit temperature exceeding
the maximum permissible surface temperature, e.g. in a fault scenario
3.35
thermal insulation
material having air- or gas-filled pockets, void spaces, or heat-reflecting surfaces that, when
properly applied, retards the transfer of heat
3.36
trace heater
device designed for the purpose of producing heat on the principle of electrical resistance and
typically composed of one and/or more metallic conductors or an electrically conductive
material, suitably electrically insulated and protected
3.37
trace heater unit
(trace heater set)
series trace heater cable, parallel trace heater cable, trace heater pad or trace heater panel
suitably terminated in conformity with the manufacturer’s instructions
3.38
trace heating
utilization of electric trace heater cables, pads, panels and support components, externally
applied and used to raise or maintain the temperature of contents in piping, tanks and
associated equipment
3.39
trace ratio
the ratio of trace heater length to pipe length

---------------------- Page: 15 ----------------------

60079-30-1 © IEC:2007 – 21 –
3.40
type test
conformity test made on one or more items representative of the production
[IEV 151-16-16]
3.41
weather barrier
material that, when installed on the outer surface of thermal insulation, protects the thermal
insulation from water or other liquids, from physical damage caused by sleet, wind or
mechanical abuse and from deterioration caused by solar radiation or atmospheric
contamination
3.42
workpiece
object to which a trace heater is applied
NOTE Examples include process equipment such as piping, vessels, tanks, valves, instruments and similar
equipment.
4 General requirements
4.1 General
Electrical resistance trace heating within the scope of this standard shall be designed and
constructed so as to ensure electrical, thermal and mechanical durability and reliable
performance so that, in normal use, it poses no danger to the user or the surroundings.
Electrical resistance trace heaters and integral components shall comply with the
requirements of IEC 60079-0 as supplemented and modified by the requirements of this
standard. Electrical resistance trace heater terminations identified as separate components
shall comply with the requirements of one or more of the types of protection listed in
IEC 60079-0 suitable for the application, which may be supplemented and modified by the
requirements of this standard.
Trace heaters shall be provided with a metallic braid or metallic sheath that shall cover at
least 70 % of the surface.
Trace heaters which are identified for use only in areas with a low risk of mechanical damage
are subjected to a reduced load in the impact test in 5.1.5 and a reduced force in the
deformation test in 5.1.6, and shall be clearly marked as specified in 6.3.
Trace heaters may be supplied with additional mechanical protection to meet the
requirements of this standard if they are supplied as an integral assembly (prefabricated), and
that contain the following statement in the instructions: “ This mechanical covering shall not
be removed and the trace heaters shall not be operated without the mechanical covering
being in place”.
The manufacturer shall declare the maximum withstand temperature in degrees Celsius. The
materials used in the trace heater shall withstand a temperature of no less than the
manufacturer's declared maximum withstand temperature +20 K, when tested in accordance
with 5.1.11.
In this standard, Clause 7 of IEC 60079-0 does no
...

6/29(16., R6,67SU(1

35('67$1'$5'
GHFHPEHU
(NVSOR]LYQHDWPRVIHUH±GHO(OHNWULþQLXSRURYQLJUHOQLWUDNRYL±
6SORãQRLQ]DKWHYH]DSUHVNXãDQMH
([SORVLYHDWPRVSKHUHV3DUW(OHFWULFDOUHVLVWDQFHWUDFHKHDWLQJ*HQHUDO
DQGWHVWLQJUHTXLUHPHQWV
,&6 5HIHUHQþQDãWHYLOND

R6,67SU(1HQ
�������������� ��� �������������������������������������������������������������� ����� ����������!�����"�#$����%&�������������’� �����������( �����)� �&!������� ������*��������+� ��,�����������%������ �-� �.� �������������

---------------------- Page: 1 ----------------------
31/661/FDIS
FINAL DRAFT INTERNATIONAL STANDARD
PROJET FINAL DE NORME INTERNATIONALE
Project number IEC 60079-30-1 Ed. 1.0
Numéro de projet
IEC/TC or SC CEI/CE ou SC Secretariat / Secrétariat
TC 31 United Kingdom

Submitted for parallel voting in CENELEC
Distributed on / Diffusé le Voting terminates on / Vote clos le
Soumis au vote parallèle au CENELEC
2006-09-29 2006-12-01
Also of interest to the following committees Supersedes document
Intéresse également les comités suivants Remplace le document
TC 18 31/584/CDV and 31/624/RVC
Functions concerned
Fonctions concernées
Safety EMC Environment Quality assurance
Sécurité CEM Environnement Assurance de la qualité
INTERNATIONAL ELECTROTECHNICAL COMMISSION COMMISSION ÉLECTROTECHNIQUE INTERNATIONALE
THIS DOCUMENT IS A DRAFT DISTRIBUTED FOR APPROVAL. IT MAY NOT BE REFERRED TO AS AN INTERNATIONAL STANDARD UNTIL PUBLISHED
AS SUCH.
IN ADDITION TO THEIR EVALUATION AS BEING ACCEPTABLE FOR INDUSTRIAL, TECHNOLOGICAL, COMMERCIAL AND USER PURPOSES, FINAL
DRAFT INTERNATIONAL STANDARDS MAY ON OCCASION HAVE TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL TO BECOME STANDARDS
TO WHICH REFERENCE MAY BE MADE IN NATIONAL REGULATIONS.

CE DOCUMENT EST UN PROJET DIFFUSÉ POUR APPROBATION. IL NE PEUT ÊTRE CITÉ COMME NORME INTERNATIONALE AVANT SA PUBLICATION
EN TANT QUE TELLE.
OUTRE LE FAIT D'ÊTRE EXAMINÉS POUR ÉTABLIR S'ILS SONT ACCEPTABLES À DES FINS INDUSTRIELLES, TECHNOLOGIQUES ET COMMERCIALES,
AINSI QUE DU POINT DE VUE DES UTILISATEURS, LES PROJETS FINAUX DE NORMES INTERNATIONALES DOIVENT PARFOIS ÊTRE EXAMINÉS EN
VUE DE LEUR POSSIBILITÉ DE DEVENIR DES NORMES POUVANT SERVIR DE RÉFÉRENCE DANS LES RÈGLEMENTATIONS NATIONALES.

Title
IEC 60079-30-1 Ed. 1.0: Explosive atmospheres - Part 30-1: Electrical resistance
trace heating - General and testing requirements

Titre
CEI 60079-30-1 Ed. 1.0: Atmosphères explosives - Partie 30-1: Traçage par
résistance électrique - Exigences générales et d'essais



ATTENTION ATTENTION
VOTE PARALLÈLE IEC – CENELEC
CEI – CENELEC PARALLEL VOTING
L’attention des Comités nationaux de la CEI, membres du The attention of IEC National Committees, members of
CENELEC, est attirée sur le fait que ce projet final de CENELEC, is drawn to the fact that this final Draft
Norme internationale est soumis au vote parallèle. Un International Standard (DIS) is submitted for parallel
bulletin de vote séparé pour le vote CENELEC leur sera voting. A separate form for CENELEC voting will be sent to
envoyé par le Secrétariat Central du CENELEC. them by the CENELEC Central Secretariat.

Copyright © 2006 International Electrotechnical Commission, IEC. All rights reserved. It is
permitted to download this electronic file, to make a copy and to print out the content for the sole
purpose of preparing National Committee positions. You may not copy or "mirror" the file or
printed version of the document, or any part of it, for any other purpose without permission in
writing from IEC.
FORM FDIS (IEC)/FORMULAIRE FDIS (CEI) 2002-08-08

---------------------- Page: 2 ----------------------
60079-30-1/FDIS © IEC – 2 –
CONTENTS
FOREWORD.3
INTRODUCTION.5

1 Scope.6
2 Normative references .6
3 Terms and definitions.6
4 General requirements .11
4.1 General .11
4.2 Terminations and connections .11
4.3 Circuit protection requirements for branch circuits .12
4.4 Control and temperature requirements .12
5 Testing .13
5.1 Type tests .13
5.2 Routine tests .26
6 Marking .26
6.1 Product markings for trace heaters.26
6.2 Markings for field-assembled components .27
6.3 Installation instructions.27

Figure 1 – Flammability test.15
Figure 2 – Impact test .16
Figure 3 – Cold bend test – Type test .18
Figure 4 – Integral components resistance to water test.19
Figure 5 – Verification of rated output .21
Figure 6 – Verification of sheath temperature using system approach .24
Figure 7 – Maximum sheath temperature using the product classification approach .25

Table 1 – Test voltages for the dielectric test.14

---------------------- Page: 3 ----------------------
60079-30-1/FDIS © IEC – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________

EXPLOSIVE ATMOSPHERES –

Part 30-1: Electrical resistance trace heating –
General and testing requirements


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 60079-30-1 has been prepared by IEC technical committee 31:
Equipment for explosive atmospheres.
This edition cancels and replaces the first edition of IEC 62086-1 published in 2001 and
constitutes a technical revision.
The general revisions and updating to produce the first edition of IEC 60079-30-1, with
respect to former edition of IEC 62086-1, are a result of national comments received.

---------------------- Page: 4 ----------------------
60079-30-1/FDIS © IEC – 4 –
The main technical differences, apart from the general revision and updating of former edition
of IEC 62086-1, are as follows:
a) the inclusion of thermal safety requirements for the manufacturer’s quality programme;
b) the inclusion of a 14 day water resistance test;
c) the further harmonization of this edition with several national standards.
This Part 30-1 is intended to be used in conjunction with the first edition of IEC 60079-30-2:
2006, Explosive atmospheres – Part 30-2: Electrical resistance trace heating – Application
guide for design, installation and maintenance.
The text of this standard is based on the following documents:
FDIS Report on voting
31/XX/FDIS 31/XX/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.
The list of all parts of 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
1
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.
___________
)
1
The National Committees are requested to note that for this publication the maintenance result date is 2011.

---------------------- Page: 5 ----------------------
60079-30-1/FDIS © IEC – 5 –
INTRODUCTION
This part of IEC 60079 is intended to provide a comprehensive overview of the essential
requirements and testing appropriate to electric surface heating equipment used in explosive
gas atmospheres. The requirements of this standard are considered to be the minimum
requirements for zone 1 or zone 2. While some of this work already exists in national
standards or international standards, this standard has collated much of this existing work and
considerably added to it.

---------------------- Page: 6 ----------------------
60079-30-1/FDIS © IEC – 6 –
EXPLOSIVE ATMOSPHERES –

Part 30-1: Electrical resistance trace heating –
General and testing requirements



1 Scope
This part of IEC 60079 specifies general and testing requirements for electrical resistance
trace heaters for application in explosive gas atmospheres. The standard covers trace heaters
that may comprise either factory- or field- (work-site) assembled units, and which may be
series heating cables, parallel heating cables or heating pads and heating panels that have
been assembled and/or terminated in accordance with the manufacturer’s instructions.
This standard also includes requirements for termination assemblies and control methods
used with trace heating. The hazardous areas referred to by this standard are those defined in
IEC 60079-10.
Where a requirement of this standard conflicts with a requirement of IEC 60079-0, the
requirement of this standard shall take precedence.
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(151), International Electrotechnical Vocabulary (IEV) – Part 151: Electrical and
magnetic devices
IEC 60079-0:2004, Electrical apparatus for explosive gas atmospheres – Part 0: General
requirements
IEC 60079-7:2001, Electrical apparatus for explosive gas atmospheres – Part 7: Increased
safety ‘e’
IEC 60079-10:2002, Electrical apparatus for explosive gas atmospheres – Part 10:
Classification of hazardous areas
IEC 60079-30-2, Explosive atmospheres – Part 30-2: Electrical resistance trace heating –
Application guide for design, installation and maintenance
IEC 60364-5-55, Electrical installations of buildings – Part 5-55: Selection and erection of
electrical equipment – Other equipment
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 60079-0 and
IEC 60079-7 as well as the following apply.

---------------------- Page: 7 ----------------------
60079-30-1/FDIS © IEC – 7 –
2
NOTE Additional definitions applicable to explosive atmospheres can be found in IEC 60050-426 .
3.1
ambient temperature
temperature surrounding the object under consideration. Where electrical trace heaters are
enclosed in thermal insulation, the ambient temperature is the temperature exterior to such
thermal insulation
3.2
branch circuit
that portion of the wiring installation between the overcurrent device protecting the circuit and
the trace heater unit(s)
3.3
connections (terminations)
3.3.1
cold lead
electrically insulated conductor or conductors used to connect a trace heater to the branch
circuit and designed so that it does not produce significant heat
3.3.2
end termination
termination, which may be heat producing, applied to a trace heater at the end opposite that
where the power is supplied
3.3.3
power termination
termination applied to the end of a trace heater at which the power is supplied
3.4
tee
electrical connection of trace heaters, in series or in parallel, to accommodate a tee or branch
3.5
dead leg
segment of process piping segregated from the normal flow pattern for the purpose of
providing a heat-loss reference
3.6
design loading
minimum power that will meet the design requirements, in the worst conditions, after voltage
and resistance tolerances and appropriate safety factors have been considered
3.7
factory-fabricated
trace heaters, including the necessary terminations and connections, assembled into units or
sets
___________
2
IEC 60050(426), International Electrotechnical Vocabulary (IEV) – Chapter 426: Electrical apparatus for
explosive atmospheres

---------------------- Page: 8 ----------------------
60079-30-1/FDIS © IEC – 8 –
3.8
field-assembled
trace heaters supplied in bulk with terminating components to be assembled at the work site
3.9
heat loss
energy flow from a pipe, vessel or equipment to its surroundings
3.10
heat sink
part that conducts and dissipates heat away from a workpiece
NOTE Typical heat sinks are pipe shoes, pipe supports and items of large mass such as valve actuators or pump
bodies.
3.11
heat-transfer aids
thermally conductive materials, such as metallic foils or heat-transfer compounds used to
increase the heat-transfer efficiency from trace heaters to the workpiece
3.12
heating pad
trace heater comprising series- or parallel-connected elements having sufficient flexibility to
conform to the shape of the surface to be heated
3.13
heating panel
non-flexible trace heater comprising series- or parallel-connected elements fabricated to
conform to the general shape of the surface to be heated
3.14
high-limit temperature
maximum allowable temperature of the system, including piping, fluid and heating system
3.15
maximum withstand temperature
maximum operating or exposure temperature that will not adversely effect the thermal stability
of the trace heater and its component parts
3.16
metallic covering
metal sheath or braid used to provide physical protection for a trace heater, and may provide
an electrical earth path
3.17
minimum ambient temperature
lowest ambient temperature specified at which heat-loss calculations are based and the trace
heating is operable and performs according to the specified requirements
3.18
operating voltage
actual voltage applied to the trace heater when in service

---------------------- Page: 9 ----------------------
60079-30-1/FDIS © IEC – 9 –
3.19
overjacket
continuous layer of insulating material applied outside the metallic sheath, screen or
armouring to protect against corrosion
3.20
parallel trace heater(s)
heating elements that are electrically connected in parallel, either continuously or in zones, so
that the watt density per lineal length is maintained, irrespective of any change in length for
the continuous type or for any number of discrete zones
3.21
power density
power output in watts per linear metre for trace heater cables and cable units, and in watts
per square metre for trace heater pads and panels and trace heater pad and panel units
3.22
rated output
total power or power per unit length or unit surface area of a trace heater, at rated voltage,
temperature and length, which is normally expressed in watts, watts per metre or watts per
square metre
3.23
rated voltage
voltage to which operating and performance characteristics of trace heaters are referred
3.24
routine test
conformity test made on each individual item during or after manufacture
[IEV 151-16-17]
3.25
series trace heater(s)
heating elements electrically connected in series with a single current path and with a specific
resistance at a given temperature for a given length
3.26
sheath
uniform and continuous metallic or non-metallic outer covering enclosing the trace heater
used to provide protection against influence from the surroundings (corrosion, moisture etc.).
See overjacket, 3.19
3.27
sheath temperature
temperature of the outermost continuous covering that may be exposed to the surrounding
atmosphere
3.28
stabilized design
concept where the temperature of the trace heater will, by design and use, stabilize below the
high-limit temperature, under the most unfavourable conditions, without the need for a
protective system to limit the temperature
3.29
start-up current
the current response of a trace heater following energization

---------------------- Page: 10 ----------------------
60079-30-1/FDIS © IEC – 10 –
3.30
system documentation
information provided by the supplier to allow satisfactory understanding, installation and safe
use of the trace heating system
3.31
temperature alarm device
serves to activate an alarm when the sensor temperature is outside the specified temperature
range
3.32
temperature control device
serves to maintain the temperature within a specified temperature range
3.33
temperature controller
device or combination of devices incorporating a means of sensing temperature and of
controlling the power to the trace heater
3.34
temperature limiting device
serves to switch off power to the trace heater to prevent the high-limit temperature exceeding
the maximum permissible surface temperature, e.g. in a fault scenario
3.35
thermal insulation
material having air- or gas-filled pockets, void spaces, or heat-reflecting surfaces that, when
properly applied, retards the transfer of heat
3.36
trace heater
device designed for the purpose of producing heat on the principle of electrical resistance and
typically composed of one and/or more metallic conductors or an electrically conductive
material, suitably electrically insulated and protected
3.37
trace heater unit
(trace heater set)
series trace heater cable, parallel trace heater cable, trace heater pad or trace heater panel
suitably terminated in conformity with the manufacturer’s instructions
3.38
trace heating
utilization of electric trace heater cables, pads, panels and support components, externally
applied and used to raise or maintain the temperature of contents in piping, tanks and
associated equipment
3.39
trace ratio
the ratio of trace heater length to pipe length
3.40
type test
conformity test made on one or more items representative of the production
[IEV 151-16-16]

---------------------- Page: 11 ----------------------
60079-30-1/FDIS © IEC – 11 –
3.41
weather barrier
material that, when installed on the outer surface of thermal insulation, protects the thermal
insulation from water or other liquids, from physical damage caused by sleet, wind or
mechanical abuse and from deterioration caused by solar radiation or atmospheric
contamination
3.42
workpiece
object to which a trace heater is applied
NOTE Examples include process equipment such as piping, vessels, tanks, valves, instruments and similar
equipment.
4 General requirements
4.1 General
Electrical resistance trace heating within the scope of this standard shall be designed and
constructed so as to ensure electrical, thermal and mechanical durability and reliable
performance so that, in normal use, it poses no danger to the user or the surroundings.
Electrical resistance trace heaters and integral components shall comply with the
requirements of IEC 60079-0 as supplemented and modified by the requirements of this
standard. Electrical resistance trace heater terminations identified as separate components
shall comply with the requirements of one or more of the types of protection listed in
IEC 60079-0 suitable for the application, which may be supplemented and modified by the
requirements of this standard.
Trace heaters shall be provided with a metallic braid or metallic sheath that shall cover at
least 70 % of the surface.
Trace heaters which are identified for use only in areas with a low risk of mechanical damage
are subjected to a reduced load in the impact test in 5.1.5 and a reduced force in the
deformation test in 5.1.6, and shall be clearly marked as specified in 6.3.
Trace heaters may be supplied with additional mechanical protection to meet the
requirements of this standard if they are supplied as an integral assembly (prefabricated), and
that contain the following statement in the instructions: “ This mechanical covering shall not
be removed and the trace heaters shall not be operated without the mechanical covering
being in place”.
The manufacturer shall declare the maximum withstand temperature in degrees Celsius. The
materials used in the trace heater shall withstand a temperature of no less than the
manufacturer's declared maximum withstand temperature +20 K, when tested in accordance
with 5.1.11.
In this standard, Clause 7 of IEC 60079-0 does not apply to electrical insulating materials of
trace heaters.
4.2 Terminations and connections
Terminations and connections may be identified as an integral part of a trace heater, or may
be identified separately, in which case they are regarded as Ex components in accordance
with Clause 13 of IEC 60079-0. Integral terminations and connections are tested as part of a
representative trace heater unit; see 5.1.1.

---------------------- Page: 12 ----------------------
60079-30-1/FDIS © IEC – 12 –
4.3 Circuit protection requirements for branch circuits
The minimum requirements for trace heating systems for use in explosive gas atmospheres
are as follows:
a) a means of isolating all line conductors from the supply;
b) over-current protection provided for each branch circuit;
c) a means of protecting against earth faults which depend on the type of system earthing
(see IEC 60364-5-55 for definitions).
For TT and TN systems using earth-fault protective devices:
d) The trace heater branch circuit protection shall be capable of interrupting high-impedance
earth faults as well as short-circuit faults. This shall be accomplished by an earth-fault
protective device, or a controller with earth-fault interruption capability for use in
conjunction with suitable circuit protection. The preferred trip level for adjustable devices
is 30 mA above any inherent capacitive leakage characteristic of the heater as specified
by the trace heater supplier. Where conditions of maintenance and supervision ensure that
only qualified persons will service the installed systems, and continued circuit operation is
necessary for the safe operation of the equipment or processes, earth-fault detection
without interruption is acceptable if alarmed in a manner to ensure an acknowledged
response.
NOTE The requirements of a), b), c) and d) may be performed by one device.
For IT systems:
e) an electrical insulation monitoring device shall be installed to disconnect the supply
whenever the electrical resistance is not greater than 50 Ω/V of rated voltage.
4.4 Control and temperature requirements
4.4.1 General
A trace heating system shall be designed so that under all conditions that may reasonably be
foreseen the surface temperature of the trace heaters is limited to the temperature
classification or ignition temperature, less 5 K for temperatures less than or equal to 200 °C
or less 10 K for temperatures greater than 200 °C. This shall be achieved either by a
stabilized design in accordance with 4.4.2, or by the use of temperature control devices in
accordance with 4.4.3 to limit the maximum equipment temperature.
When multiple trace heaters (especially on pipes with different flow conditions) are grouped
together under a single surface-sensing temperature control device, each design condition
shall be analysed as a stabilized pipe design.
4.4.2 Stabilized design for zone 1 and zone 2 applications
Stabilized design applications, in which the maximum surface temperature of the trace heater
is determined without thermostatic control, shall employ either the systems approach
specified in 5.1.13.2 or the product classification approach specified in 5.1.13.3.

---------------------- Page: 13 ----------------------
60079-30-1/FDIS © IEC – 13 –
4.4.3 Controlled design
Controlled design applications, which require the use of a temperature control device to
limit the maximum surface temperature, shall comply with a) for zone 1 and either a) or b) for
zone 2:
a) for zone 1 applications: a protective device such as a temperature limiter shall be provided
that will de-energize the system to prevent exceeding the maximum permissible surface
temperature. In case of an error by, or damage to the sensor, the heating system shall be
de-energized before replacing the defective equipment. The protective device shall
operate independently from the temperature controller. The protective device shall have
the following characteristics:
1) Resetting by hand only
2) Resetting possible only after the normal operating conditions have returned, or if the
switching state is monitored continuously
3) Tool or keyed lock required for resetting
4) Temperature setting secured and locked to prevent manipulation
5) A control that will de-energize the circuit if the sensor fails
b) for zone 2 applications: a single temperature controller with failure announcement may be
used. If so, provision of adequate monitoring of such an announcement, such as 24 h
surveillance, shall be made.
NOTE If the control devices are not being provided by the manufacturer, sufficient instructions for selection and
installation should be provided.
5 Testing
5.1 Type tests
5.1.1 General
The provisions of 26.1 of IEC 60079-0 apply with the following additions. Samples of trace
heaters at least 3 m in length, unless otherwise specified, shall be selected for testing. Tests
shall be conducted at a temperature between 10 °C and 40 °C unless otherwise stated.
Terminations and connections that are to be installed as an integral part of the trace heat
...