IEC 60079-15:2010

Explosive atmospheres - Part 15: Equipment protection by type of protection "n"

IEC 60079-15:2010 specifies requirements for the construction, testing and marking for Group II electrical equipment with type of protection, "n" intended for use in explosive gas atmospheres. This standard applies to electrical equipment where the rated voltage does not exceed 15 kV r.m.s. a.c. or d.c. This standard supplements and modifies the general requirements of IEC 60079-0, except as indicated in Table 1. Where a requirement of this standard conflicts with a requirement of IEC 60079-0, the requirement of this standard takes precedence. The significant technical changes with respect to the previous edition are as follows:
- addition of equipment protection levels;
- removal of the requirements for energy-limited "nL" and associated energy limited apparatus "[nL]";
- removal of the requirements for encapsulated Devices "nC";
- requirements for electrical connections expanded and clarified;
- requirements for electrical connections expanded and clarified;
- requirements for luminaire ballasts expanded and clarified;
- requirements for evaluation and testing of motor rotors clarified;
- 15 kV limit for equipment protection by type of protection "n" added;
- spacing requirement for voltages above 10 kV modified;
- requirements for restricted breathing enclosures modified;
- modification to requirements for motor rotors and stators;
- addition of Annex A (informative);
- and undated references to IEC 60079-0 included.
This publication is to be read in conjunction with IEC 60079-0:2007. The contents of the Interpretation sheet 1 of September 2016 have been included in this copy.

Atmosphères explosives - Partie 15: Protection du matériel par mode de protection "n"

La CEI 60079-15:2010 spécifie les exigences de construction, d'essai et de marquage du matériel électrique du Groupe II avec mode de protection "n" destiné à être utilisé en atmosphère explosive gazeuse. La présente norme s'applique au matériel électrique dont la tension assignée ne dépasse pas 15 kV efficace, c.a. ou c.c. La présente norme complète et modifie les exigences générales de la CEI 60079-0, à l'exception de celles qui sont indiquées dans le Tableau 1. Si une exigence de la présente norme est en conflit avec une exigence de la CEI 60079-0, l'exigence de la présente norme prévaut. Les modifications techniques importantes par rapport à l'édition précédente sont les suivantes:
- ajout des niveaux de protection des matériels;
- retrait des exigences pour les appareils "nL" à énergie limitée et les appareils "[nL]" à énergie limitée associés;
- retrait des exigences pour les dispositifs encapsulés "nC";
- exigences étendues et clarifiées pour les raccordements électriques;
- exigences étendues et clarifiées pour les ballasts pour luminaire;
- exigences clarifiées pour l'évaluation et les essais sur les rotors de moteur;
- limite de 15 kV ajoutée pour la protection du matériel du mode de protection "n";
- exigence en matière d'espacement modifiée pour les tensions supérieures à 10 kV;
- exigences modifiées pour les enveloppes à respiration limitée;
- modification des exigences pour les stators et rotors de moteurs;
- ajout de l'Annexe A (informative);
- introduction de références non datées à la CEI 60079-0.
Cette publication doit être lue conjointement avec la CEI 60079-0:2007. Le contenu de la feuille d'interprétation 1 de septembre 2016 a été pris en considération dans cet exemplaire.

General Information

• Status: Published
• Publication Date: 27-Jan-2010
• ICS: 29.260.20 - Electrical apparatus for explosive atmospheres
• Technical Committee: TC 31 - Equipment for explosive atmospheres
• Drafting Committee: MT 60079-15 - TC 31/MT 60079-15
• Current Stage: DELPUB - Deleted Publication
• Completion Date: 08-Dec-2017

Relations

• Revised: IEC 60079-15:2017 - Explosive atmospheres - Part 15: Equipment protection by type of protection "n"
• Effective Date: 05-Sep-2023
• Revises: IEC 60079-15:2005 - Electrical apparatus for explosive gas atmospheres - Part 15: Construction, test and marking of type of protection "n" electrical apparatus
• Effective Date: 05-Sep-2023
• Revised: IEC 60079-15:2010/ISH1:2016 - Intrepretation sheet 1 - Explosive atmospheres - Part 15: Equipment protection by type of protection "n"
• Effective Date: 05-Sep-2023

Standards Content (Sample)

IEC 60079-15 ®
Edition 4.0 2010-01
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Explosive atmospheres –
Part 15: Equipment protection by type of protection "n"

Atmosphères explosives –
Partie 15: Protection du matériel par mode de protection « n »

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IEC 60079-15 ®
Edition 4.0 2010-01
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Explosive atmospheres –
Part 15: Equipment protection by type of protection "n"

Atmosphères explosives –
Partie 15: Protection du matériel par mode de protection « n »

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
XB
CODE PRIX
ICS 29.260.20 ISBN 978-2-88910-045-3
INTERNATIONAL ELECTROTECHNICAL COMMISSION

____________
IEC 60079-15
Edition 4.0  2010-01
EXPLOSIVE ATMOSPHERES –
Part 15: Equipment protection by type of protection "n"

INTERPRETATION SHEET 1
This interpretation sheet has been prepared by IEC technical committee 31: Equipment for
explosive atmospheres.
The text of this interpretation sheet is based on the following documents:
ISH Report on voting
31/1259/ISH 31/1273/RVD
Full information on the voting for the approval of this interpretation sheet can be found in the
report on voting indicated in the above table.
___________
by type of protection "n"
Question:
Do the requirements given in 8.3 prohibit the use of a terminal box opened to the interior of a
motor rated 1 kV or greater, provided the interior of the machine has an ingress protection of
IP54 or greater?
8.3 Terminal boxes
Terminal boxes attached to machines operating at voltages up to 1 kV, may be opened to the
interior of the machine, only when the IP rating of the machine is IP44 or higher. The external
IP protection of the box shall be not less than IP54, as determined in accordance with
IEC 60079-0.
ICS 29.260.20
– 2 – IEC 60079-15:2010/ISH1:2016  IEC 2016

Answer:
No. As long as the interior of the machine has an ingress protection of IP54 or greater,

determined in accordance with IEC 60079-0, there is no limitation to less than 1 kV. If the

interior of the machine has an ingress rating of IP44 or lower, the use of a terminal box open

to the interior of a motor rated 1 kV or greater is not permitted.

NOTE Many manufacturers opt to declare IP44 for the machine for certification purposes, whilst claiming a rating

of IP54 or higher, by assessment, for contractual purposes in order to avoid the difficult testing required for

certification of the IP of larger machines. As such, this additional IP rating need only comply with IEC 60529 or
IEC 60034-5 as applicable, and not with any of the testing detailed in IEC 60079-0.

– 2 – 60079-15 © IEC:2010
CONTENTS
FOREWORD.8

1 Scope.10

2 Normative references .14

3 Terms and definitions .15

4 General .17

4.1 Equipment grouping and temperature classification .17

4.2 Potential ignition sources .17

5 Temperatures .17
5.1 Maximum surface temperature .17
5.2 Small components .18
6 Requirements for electrical equipment.18
6.1 General .18
6.2 Opening times .18
6.3 Minimum degree of protection .18
6.3.1 General .18
6.3.2 Degree of protection provided by installation .18
6.4 Clearances, creepage distances and separations .18
6.4.1 General .18
6.4.2 Determination of working voltage.19
6.4.3 Conformal coating .19
6.4.4 Comparative tracking index (CTI) .19
6.4.5 Measurement of creepage and clearance .19
6.4.6 Compound filled cable sealing boxes.21
6.5 Electric strength .26
6.5.1 Insulation from earth or frame.26
6.5.2 Insulation between conductive parts .26
7 Connection facilities and terminal compartments .27
7.1 General .27
7.2 Field wiring connections .27
7.2.1 General .27
7.2.2 Connections made using terminals complying with IEC 60947-7-1,
IEC 60947-7-2, IEC 60999-1, or IEC 60999-2 .28
7.2.3 Field wiring connection facilities integral to “n” equipment or
components.28
7.2.4 Connections designed to be used with cable lugs and similar devices .28
7.2.5 Connections using permanent arrangements .28
7.3 Factory connections .28
7.3.1 General .28
7.3.2 Field wiring connection methods used for factory connections .28
7.3.3 Other factory connections.28
7.3.4 Permanent connections .28
7.3.5 Pluggable connections.29
7.3.6 Terminal bridging connections .29
8 Supplementary requirements for non-sparking electrical machines .29
8.1 General .29
8.2 Machine enclosure .30

60079-15 © IEC:2010 – 3 –
8.3 Terminal boxes.30

8.4 Conduit stopping boxes, cable sealing and dividing boxes.30

8.5 Connection facilities for external conductors.30

8.6 Neutral point connections .30

8.7 Radial air gap.31

8.8 Rotor cages.31

8.8.1 Rotor cages built from bars connected to end rings .31

8.8.2 Cast rotor cages .31

8.8.3 Assessment for possible air gap sparking .31

8.9 Stator winding insulation system .32

8.10 Surface temperature limitation.33
8.10.1 Prevention of thermal ignition .33
8.10.2 Operation with a frequency convertor or a non-sinusoidal supply.33
9 Supplementary requirements for non-sparking fuses and fuse assemblies.34
9.1 Fuses .34
9.2 Temperature class of equipment.
...