Safety in electroheating installations - Part 4: Particular requirements for arc furnace installations

This clause of Part 1 is replaced by the following. Replacement: This part of IEC 60519 provides particular safety requirements for electric arc furnace installations and its operating and maintenance personnel. These safety provisions concern the protection of persons and the environment against dangers of electrical origin and also against certain dangers of non-electrical origin. This standard is applicable to electroheating installations such as: a) Furnaces for direct arc heating, forming arcs between the electrode and metal such as the electric arc furnace using alternating current (EAFac) or direct current (EAFdc), and ladle furnace (LF); b) Furnaces for arc-resistance heating forming arcs between the electrode and the charge material or heating the charge material by the Joule effect, such as the submerged arc furnace using alternating current (SAFac), or direct current (SAFdc).

Sicherheit in Elektrowärmeanlagen - Teil 4: Besondere Bestimmungen für Lichtbogenofenanlagen

Sécurité dans les installations électrothermiques - Partie 4: Exigences particulières pour les installations de fours à arc

La CEI 60519-4:2013 fournit des exigences de sécurité particulières pour les installations de fours à arc électriques et pour le personnel de service et de maintenance. Ces dispositions de sécurité concernent la protection du personnel et de l'environnement contre les dangers d'origine électrique et certains dangers d'origine non électrique. Cette quatrième édition annule et remplace la troisième édition parue en 2006. Cette édition constitue une révision technique. Cette édition inclut les modifications techniques majeures suivantes par rapport à l'édition précédente: - La structure a été amendée et alignée sur celle de la CEI 60519-1:2010; - La classification (Article 4) a été adaptée aux détails par rapport à la tension secondaire d'un four à arc électrique; - Toutes les dispositions ont été reformulées et le texte relatif aux fours à arc électriques est plus concis; - Dans les Annexes AA, BB et CC, les parties relatives aux points suivants ont été restructurées: détails relatifs aux conceptions haute tension et aux problèmes non électriques, mais dont il faut tenir compte dans le cadre de ces installations.

Varnost pri električnih grelnih inštalacijah - 4. del: Posebne zahteve za inštalacije obločnih peči (IEC 60519-4:2013)

General Information

Status
Published
Publication Date
02-Jan-2014
Technical Committee
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
16-Dec-2013
Due Date
20-Feb-2014
Completion Date
03-Jan-2014

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SLOVENSKI STANDARD
SIST EN 60519-4:2014
01-februar-2014
1DGRPHãþD
SIST EN 60519-4:2007

9DUQRVWSULHOHNWULþQLKJUHOQLKLQãWDODFLMDKGHO3RVHEQH]DKWHYH]DLQãWDODFLMH

REORþQLKSHþL ,(&

Safety in electroheating installations - Part 4: Particular requirements for arc furnace

installations
Sicherheit in Elektrowärmeanlagen - Teil 4: Besondere Bestimmungen für
Lichtbogenofenanlagen

Sécurité dans les installations électrothermiques - Partie 4: Exigences particulières pour

les installations de fours à arc
Ta slovenski standard je istoveten z: EN 60519-4:2013
ICS:
25.180.10 (OHNWULþQHSHþL Electric furnaces
SIST EN 60519-4:2014 en

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
SIST EN 60519-4:2014
---------------------- Page: 2 ----------------------
SIST EN 60519-4:2014
EUROPEAN STANDARD
EN 60519-4
NORME EUROPÉENNE
August 2013
EUROPÄISCHE NORM
ICS 25.180.10 Supersedes EN 60519-4:2006
English version
Safety in electroheating installations -
Part 4: Particular requirements for arc furnace installations
(IEC 60519-4:2013)
Sécurité dans les installations Sicherheit in Elektrowärmeanlagen -
électrothermiques - Teil 4: Besondere Bestimmungen für
Partie 4: Exigences particulières pour les Lichtbogenofenanlagen
installations de fours à arc (IEC 60519-4:2013)
(CEI 60519-4:2013)

This European Standard was approved by CENELEC on 2013-07-24. 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 CEN-CENELEC Management Centre 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 CEN-CENELEC Management Centre has the same status as the official versions.

CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus,

the Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany,

Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland,

Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom.

CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Avenue Marnix 17, B - 1000 Brussels

© 2013 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.

Ref. No. EN 60519-4:2013 E
---------------------- Page: 3 ----------------------
SIST EN 60519-4:2014
EN 60519-4:2013 - 2 -
Foreword

The text of document 27/904/FDIS, future edition 4 of IEC 60519-4, prepared by IEC/TC 27 "Industrial

electroheating and electromagnetic processing" was submitted to the IEC-CENELEC parallel vote and

approved by CENELEC as EN 60519-4:2013.
The following dates are fixed:
(dop) 2014-04-24
• latest date by which the document has
to be implemented at national level by
publication of an identical national
standard or by endorsement
(dow) 2016-07-24
• latest date by which the national
standards conflicting with the
document have to be withdrawn

The clauses of parts of the EN 60519 series (hereinafter called Particular requirements) supplement or

modify the corresponding clauses of EN 60519-1:2011 (General requirements hereinafter called

Part 1).

This part of EN 60519 is to be read in conjunction with Part 1. It supplements or modifies the

corresponding clauses of Part 1. Where the text indicates an "addition" to or a "replacement" of the

relevant provision of Part 1, these changes are made to the relevant text of Part 1. Where no change

is necessary, the words "This clause of Part 1 is applicable" are used. When a particular subclause of

Part 1 is not mentioned in this part, that subclause applies as far as is reasonable.

Additional specific provisions to those in Part 1, given as individual clauses or subclauses, are

numbered starting from 101.
NOTE The following numbering system is used:

– subclauses, tables and figures that are numbered starting from 101 are additional to those in Part 1;

– unless notes are in a new subclause or involve notes in Part 1, they are numbered starting from 101, including those in a

replaced clause or subclause;
– additional annexes are lettered AA, BB, etc.
This document supersedes EN 60519-4:2006.

EN 60519-4:2013 includes the following significant technical changes with respect to

EN 60519-4:2006:
– The structure has been amended and adjusted to EN 60519-1:2011;

– The classification (Clause 4) has been adapted to details with respect to secondary voltage in

electric arc furnace installations;

– All provisions have been redrafted and the text is more concise with respect to EAF;

– Annexes AA, BB and CC have been restructured, with respect to details concerning high voltage

designs and non-electrical issues, however to be aware of in those installations.

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. CENELEC [and/or CEN] shall not be held responsible for identifying any or all such

patent rights.

This standard covers the Principle Elements of the Safety Objectives for Electrical Equipment

Designed for Use within Certain Voltage Limits (LVD - 2006/95/EC).
---------------------- Page: 4 ----------------------
SIST EN 60519-4:2014
- 3 - EN 60519-4:2013
Endorsement notice

The text of the International Standard IEC 60519-4:2013 was approved by CENELEC as a European

Standard without any modification.

In the official version, for Bibliography, the following note has to be added for the standard indicated:

IEC 60073:2002 NOTE Harmonised as EN 60073:2002 (not modified).
---------------------- Page: 5 ----------------------
SIST EN 60519-4:2014
EN 60519-4:2013 - 4 -
Annex ZA
(normative)
Normative references to i nternational publications
with their corresponding European publications

The following documents, in whole or in part, are normatively referenced in this document and are

indispensable for its application. 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
IEC/TS 60479-1 - Effects of current on human beings and - -
livestock -
Part 1: General aspects
IEC 60519-1 2010 Safety in electroheating installations - EN 60519-1 2011
+ corr. November 2012 Part 1: General requirements
IEC 60676 - Industrial electroheating equipment - Test EN 60676 -
methods for direct arc furnaces
IEC 60683 - Industrial electroheating equipment - Test EN 60683 -
methods for submerged arc furnaces
---------------------- Page: 6 ----------------------
SIST EN 60519-4:2014
IEC 60519-4
Edition 4.0 2013-06
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Safety in electroheating installations –
Part 4: Particular requirements for arc furnace installations
Sécurité dans les installations électrothermiques –
Partie 4: Exigences particulières pour les installations de fours à arc
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CODE PRIX T
ICS 25.180.10 ISBN 978-2-83220-873-1

Warning! Make sure that you obtained this publication from an authorized distributor.

Attention! Veuillez vous assurer que vous avez obtenu cette publication via un distributeur agréé.

® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale
---------------------- Page: 7 ----------------------
SIST EN 60519-4:2014
– 2 – 60519-4 © IEC:2013
CONTENTS

FOREWORD ........................................................................................................................... 3

1 Scope and object .............................................................................................................. 5

2 Normative references ....................................................................................................... 5

3 Terms and definitions ....................................................................................................... 5

4 Classification of electroheating equipment ........................................................................ 7

5 General requirements ....................................................................................................... 7

6 Isolation and switching ..................................................................................................... 8

7 Connections to the electrical supply network and internal connections ........................... 10

8 Protection against electric shock .................................................................................... 10

9 Equipotential bonding ..................................................................................................... 11

10 Control circuits and control functions .............................................................................. 11

11 Protection against thermal influences ............................................................................. 11

12 Protection against other hazards .................................................................................... 11

13 Marking, labelling and technical documentation .............................................................. 11

14 Commissioning, inspection, operation and maintenance ................................................. 11

Annex A (normative) Protection against electric shock – special measures .......................... 14

Annex AA (normative) Systems to assure improved safety for personnel working in

the vicinity of electrodes and other live parts of secondary circuit ......................................... 15

Annex BB (normative) Additional requirements for the safety of non-electrical

components of furnace installations ...................................................................................... 18

Annex CC (normative) Additional requirements for safety with respect to design of an

installation ............................................................................................................................ 20

Bibliography .......................................................................................................................... 23

Figure AA.1 – Arc furnace supply with HV furnace switch (or HV furnace breaker) in

open position and HV disconnector in open position ............................................................. 15

Figure AA.2 – Arc furnace supply with HV furnace switch (or HV furnace breaker) in

open position and HV earthing switch in closed position ....................................................... 15

Figure AA.3 – Arc furnace supply with buck-boost transformer or intermediate circuit

transformer ........................................................................................................................... 16

Figure AA.4 – DC furnace supply with HV furnace switch (or HV furnace breaker) in

open position and HV disconnector in open position ............................................................. 17

Figure AA.5 – DC furnace supply with HV furnace switch (or HV furnace breaker) in

closed position, valve firing pulses stopped and LV disconnector switch in open

position ................................................................................................................................. 17

---------------------- Page: 8 ----------------------
SIST EN 60519-4:2014
60519-4 © IEC:2013 – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
SAFETY IN ELECTROHEATING INSTALLATIONS –
Part 4: Particular requirements for arc furnace installations
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 itself does not provide any attestation of conformity. Independent certification bodies provide conformity

assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any

services carried out by independent certification bodies.

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 60519-4 has been prepared by IEC technical committee 27:

Industrial electroheating and electromagnetic processing.

This fourth edition cancels and replaces the third edition published in 2006. This edition

constitutes a technical revision.

This edition includes the following significant technical changes with respect to the previous

edition:
– The structure has been amended and adjusted to IEC 60519-1:2010;

– The classification (Clause 4) has been adapted to details with respect to secondary

voltage in electric arc furnace installations;

– All provisions have been redrafted and the text is more concise with respect to EAF;

– Annexes AA, BB and CC have been restructured, with respect to details concerning high

voltage designs and non-electrical issues, however to be aware of in those installations.

---------------------- Page: 9 ----------------------
SIST EN 60519-4:2014
– 4 – 60519-4 © IEC:2013
The text of this standard is based on the following documents:
FDIS Report on voting
27/904/FDIS 27/928/RVD

Full information on the voting for the approval of this standard can be found in the report on

voting indicated in the above table.

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

A list of all the parts of IEC 60519 series, under the general title Safety in electroheating

installations, can be found on the IEC website.

The clauses of parts of the IEC 60519 series (hereinafter called Particular Requirements)

supplement or modify the corresponding clauses of IEC 60519-1:2010 (General requirements

hereinafter called Part 1).

This part of IEC 60519 is to be read in conjunction with Part 1. It supplements or modifies the

corresponding clauses of Part 1. Where the text indicates an "addition" to or a "replacement"

of the relevant provision of Part 1, these changes are made to the relevant text of Part 1.

Where no change is necessary, the words "This clause of Part 1 is applicable" are used.

When a particular subclause of Part 1 is not mentioned in this part, that subclause applies as

far as is reasonable.

Additional specific provisions to those in Part 1, given as individual clauses or subclauses, are

numbered starting from 101.
NOTE The following numbering system is used:

– subclauses, tables and figures that are numbered starting from 101 are additional to those in Part 1;

– unless notes are in a new subclause or involve notes in Part 1, they are numbered starting from 101, including

those in a replaced clause or subclause;
– additional annexes are lettered AA, BB, etc.

The committee has decided that the contents of this publication will remain unchanged until

the stability date indicated on the IEC web site under "http://webstore.iec.ch" in the data

related to the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
---------------------- Page: 10 ----------------------
SIST EN 60519-4:2014
60519-4 © IEC:2013 – 5 –
SAFETY IN ELECTROHEATING INSTALLATIONS –
Part 4: Particular requirements for arc furnace installations
1 Scope and object
This clause of Part 1 is replaced by the following.
Replacement:

This part of IEC 60519 provides particular safety requirements for electric arc furnace

installations and its operating and maintenance personnel.

These safety provisions concern the protection of persons and the environment against

dangers of electrical origin and also against certain dangers of non-electrical origin.

This standard is applicable to electroheating installations such as:

a) Furnaces for direct arc heating, forming arcs between the electrode and metal such as the

electric arc furnace using alternating current (EAFac) or direct current (EAFdc), and ladle

furnace (LF);

b) Furnaces for arc-resistance heating forming arcs between the electrode and the charge

material or heating the charge material by the Joule effect, such as the submerged arc

furnace using alternating current (SAFac), or direct current (SAFdc).

NOTE For purposes of this document abbreviation EAF is used for all kinds of electric arc furnace installations.

2 Normative references
This clause of Part 1 is applicable with the following additions.
Additions:

IEC 60519-1:2010, Safety in electroheating installations – Part 1: General requirements

IEC/TS 60479-1, Effects of current on human beings and livestock – Part 1: General aspects

IEC 60676, Industrial electroheating equipment – Test methods for direct arc furnaces

IEC 60683, Industrial electroheating equipment – Test methods for submerged-arc furnaces

3 Terms and definitions
This clause of Part 1 is applicable with the following additions.
Additions:

NOTE 101 General definitions can be found in the IEC 60050 series, International Electrotechnical Vocabulary.

Terms relating to industrial electroheat are defined in IEC 60050-841. Terms relating to EAF and SAF are also

defined in IEC 60676 and IEC 60683.
---------------------- Page: 11 ----------------------
SIST EN 60519-4:2014
– 6 – 60519-4 © IEC:2013
3.101
arc furnace

furnace with a vessel, in which a metallic charge is heated mainly by electric arc using

alternating current (EAFac) or direct current (EAFdc)

[SOURCE: IEC 60050-841:2004, 841-26-05, modified – the definition has been modified and

abbreviations have been added]
3.102
arc furnace transformer

transformer changing medium/high voltage electrical supply to low voltage and high current

for an EAF

[SOURCE: IEC 60050-841:2004, 841-26-55, modified – the definition has been modified]

3.103
electric arc furnace using alternating current
EAFac

furnace, in which electric arcs between the electrodes and the process material are formed,

using three-phase alternating current
Note 1 to entry: Ladle furnace (LF) is operated under the same conditions.
Note 2 to entry: This note only applies to the French language.

[SOURCE: IEC 60050-841:2004, 841-26-07, modified – the term “alternating current arc

furnace” has been replaced by “electric arc furnace using alternating current”, the definition

has been modified, and an abbreviation and Notes 1 and 2 have been added]
3.104
electric arc furnace using direct current
EAFdc

furnace, in which the direct current is induced via a bottom electrode (anode) to the material

to be processed, forming arcs between the material and the electrode from top (cathode)

[SOURCE: IEC 60050-841:2004, 841-26-06, modified – the term “direct current arc furnace”

has been replaced by “electric arc furnace using direct current”, the definition has been

modified and an abbreviation has been added]
3.105
EAF electrode

part produced from high density graphite to transfer the electrical energy forming arcs

between tip and charge material

Note 1 to entry: In EAFdc, a bottom electrode (anode) is metallic or conductive material in the bottom of an EAF

and arcs are formed between the charge material and the graphite electrode from top (cathode).

[SOURCE: IEC 60050-841:2004, 841-26-38, modified – the term “arc furnace electrode” has

been replaced by “EAF electrode”, the definition has been modified and Note 1 has been

added]
3.106
electrode clamp

metallic, water cooled equipment to hold the electrode and supply current for arcing to the

electrode

[SOURCE: IEC 60050-841:2004, 841-26-39, modified – the definition has been editorially

improved]
---------------------- Page: 12 ----------------------
SIST EN 60519-4:2014
60519-4 © IEC:2013 – 7 –
3.107
rectifier for direct current

device by means of which alternating current is transferred into direct current for EAFdc

3.108
shell
body of EAF made from steel and covered by a roof

[SOURCE: IEC 60050-841:2004, 841-26-20, modified – the term “arc furnace shell” has

been replaced by “shell” and the definition has been modified]
3.109
submerged arc furnace
SAF

vessel in which a combined arc / resistance heating is used to melt the charged material

[SOURCE: IEC 60050-841:2004, 841-26-12, modified – the term “submerged arc-resistance

furnace” has been replaced and the definition has been modified]
4 Classification of electroheating equipment
This clause of Part 1 is applicable, except as follows:
4.2 Classification of electroheating equipment according to process frequency
4.2.1 Direct current equipment
Addition:
EAFdc and SAFdc are classified as zero (0) frequency. It creates electromagnetic
disturbances.
4.2.101 Secondary voltage

Arc furnaces can be operated with a secondary voltage above 1 000 V a.c. (1 500 V d.c.)

under preconditions as follows:

a) the EAF is switched-on on the primary side of the transformer, since there is no possibility

to switch the installation on the secondary side (except installations shown in
Figures AA.3 and AA.5);

b) the insulation of the high current conductors to ground follows the minimum relevant

standard IEC 60071-1 for secondary voltages above 1 000 V a.c.
5 General requirements
This clause of Part 1 is applicable, except as follows:
5.1 General
Additions:

5.1.101 All high voltage equipment on the furnace transformer primary side is designed,

constructed and enclosed during any operation in accordance with IEC 61936-1:

a) For arc furnaces with secondary voltage up to 1 000 V a.c. or up to 1 500 V d.c. the

minimum relevant standard IEC 60664-1 applies;
b) standard furnace operation according to the conditions, mentioned in 6.101;
---------------------- Page: 13 ----------------------
SIST EN 60519-4:2014
– 8 – 60519-4 © IEC:2013

c) visible information is given in the control room with respect to the status of the high

voltage switchgear.
5.2 Electroheating equipment
Additions:

5.2.101 Furnace installations exceeding 1 000 V a.c. shall take into account ionization

phenomena due to metallic vapour and pollution at high temperatures which may occur.

Insulation and distance between the electric phases shall be considered respectively.

5.2.102 Devices necessary for the operation (i.e. local control facilities, valve stands, lances

and manipulators) of the furnace shall be arranged within easy reach of the operator and

sufficient protection against live parts.

5.2.103 Devices for operation shall be designed and placed to prevent their unintended

activation. Devices for operation with plug connections shall be mechanically locked and shall

be designed different to other network connector.

5.2.104 Electrical equipment installed near components with high temperatures during

operation shall have sufficient thermal strength and protection.

5.2.105 Precautions shall be taken to avoid any hazard to persons due to transient voltages

which might occur during normal operation in circuits comprising transformers, inductors,

capacitors and rectifiers for direct current. Equipment shall be designed to suppress and/or

withstand high voltages (above 1 000 V) which are normal in the operation of an arc furnace.

5.2.106 Electrical equipment shall be arranged in such way, that it does not deteriorate

during normal operation due to physical and chemical effects, including heat load close to the

furnace and pollution or electromagnetic forces, created by the current during operation. In

case it is necessary, suitable measures shall be taken, i.e. gutters or protective channels.

5.6 Electromagnetic compatibility
5.6.1
Addition:

In case of EAFdc, measures shall be taken to avoid the strong magnetic field on electrical

devices, i.e. video displays, control units, valves, sensors; the magnetization of parts made

from steel shall be considered.
6 Isolation and switching
This clause of Part 1 is applicable, except as follows:
6.1 General
Addition:

In case of EAF, LF and SAF Emergency-Stop devices shall interrupt electrical power supply to

the furnace and stop all movements. Regarding EAF, the shell and electrodes shall be

brought into safe position in case it is required. Furnace cooling systems shall be kept in

function.
Additional subclauses:
---------------------- Page: 14 ----------------------
SIST EN 60519-4:2014
60519-4 © IEC:2013 – 9 –
6.101 Switching-off

The system shall be switched-off and earthed as shown in Annex AA prior any access is

allowed to the roof of an arc furnace or before working in the vicinity of the electrodes,

including the bottom electrodes of an EAFdc. Means shall be provided to prevent any

unexpected connection of the system. Visual inspection of open circuit breaker or

disconnector is necessary (e.g. by CCTV- Closed Circuit Television). Any equipment under

power in the vicinity shall be shielded effectively (for exceptions, see 8.2.102.)

During the status: “furnace breaker OFF”, all jobs, which are defined under EAF operation

conditions, can be carried out, as long as safety measures, see 14.3.106, are considered.

Normal EAF operation conditions are:
– slag level measurement;
– slipping and changing of EAF electrodes;
– refining;
– temperature measuring and sampling;
– tapping;
– deslagging;
– charging of scrap or other material etc.;
– small repair work at refractory (patching);
– maintenance of tapping hole and
– all comparable work related to exposure of the personnel.

Corresponding to IEC 61936-1 means to protect the persons working on electrical installations

shall be valid.
6.102 Buck-boost supply systems

Buck-boost supply systems (see Figure AA.3) need special care in case the operator has to

work on the electrodes. Prior to any contact with the electrodes, the furnace shall be

switched-off and all low-voltage connectors shall be earthed safely and solidly.
6.103 Special relays

Special relays for current and voltage shall trip the high-voltage circuit-breaker at any fault of

the system during the condition “Furnace-OFF” to ensure that the current-time-function C1

according to IEC/TS 60479-1 will
...

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