IE C , N EC , C EC , AT E X H a z a r d o u s Lo cati o n G u i d e
CHART 1 — What is aN IEC zone?
CHART 9 — Equipment MARKINGS
UNDERSTANDING IEC MARKINGS †
The IEC has defined 3 areas of hazardous gas or vapor release as follows:
ZONE 0
ZONE 1
Explosive Atmosphere Is Continuously Present
de
II
C
T6
Gb
•
•
•
•
•
•
Ga for zone 0
Gb for zone 1
Gc for zone 2
Temperature Class T6 = Max 85˚°C Surface
Temperature
Gas Subdivision Group-C = Acetelyne
0.1 - 10 hours/year
Type of Protection d = “flameproof”
Type of Protection e = “increased safety”
The IEC has defined 3 areas of hazardous/combustable dusts as follows:
ZONE 20
ZONE 21
Increased safety “e”
Explosion Protected Meets IEC Standards
ZONE 22
AEx = Equipment conforms to NEC
Explosive Atmosphere Is Continuously Present
Explosive Atmosphere Is Often Present
Explosive Atmosphere May Accidentally Be Present
>1000 hours/year
10-1000 hours/year
0.1 - 10 hours/year
† Alternate marking: Ex deb IIC T6.
‡ This only applies to IEC Standards only. See “Chart 10 — Understanding IEC Equipment Protection Level Requirements” below.
II
ID No. of Notified
Body of the QA
System
CE Marking
Symbol
1
EU Explosive Atmospheres
Symbol
Surface (non-mining) Equipment
REQUIREMENTS:
• Use IEC approved non-loosening screw type in IEC approved enclosures
• Control internal and external temperature
G
Equipment Category
Type of Flammable
Substance
FLAMEPROOF PLUS INCREASED SAFETY “de”
“d”
Ex
ia
IIC
T4
CHART 2 — COMPARING IEC ZONES AND NEC /CEC DIVISIONS
Ex: Conformity to IEC and ATEX Hazardous area
standards; Suitability for use in IEC and
ATEX hazardous locations
ZONE 2 / zONE 22
Division 1
Class I
Gases and Vapors
Zone
Group
d and/or e
1 or 2
II
C
Acetylene
Class
Division
Group
I
1 or 2
A
Hydrogen
d and/or e
1 or 2
II
B + H2
I
1 or 2
B
Propylene oxide, Ethyl oxide, Butadiene
d and/or e
1 or 2
II
B
I
1 or 2
B
Cyclopropane, Ethyl ether, Ethylene
d and/or e
1 or 2
II
B
I
1 or 2
C
Acetone, Benzene, Butane, Propane, Hexane, Paint solvents, Natural gas
d and/or e
1 or 2
II
A
I
1 or 2
D
Group A
I = Gas and Vapors
II = Dust
III = Fibers and Flyings
NEC®/CEC
Protection
Division 1
A = Acetylene
B = Hydrogen
C = Ethylene
D = Gasoline
E = Electrically Conductive Dust
F = Fuel Dust
G = Grain Dust
1 = Hazard normally present
2 = Hazard abnormally present
INTRINSIC SAFETY “ia” - “ib” - “ic”
•
•
•
•
•
Chart 10 — UNDERSTANDING IEC Equipment Protection Level Requirements
Protection
Afforded
Equipment Protection
Level (EPL)
Group
Ma
Group I
Very high
High
Enhanced
Performance of Protection
Equipment used in explosive atmosphere
Ga
Group II
Da
Group III
Mb
Group I
Good for use in normal and severe operating conditions
Equipment de-energized in explosive atmosphere
Gb
Group II
Used in Zones 1 and 2
Db
Group III
Good for use in normal operation or where equipment malfunctions are considered
Gc
Group II
Dc
Group III
Used in Zones 0,1 and 2
Used in zones 20, 21, and 22
Encapsulation “m”
• ZONE 1
• Epoxy or other resin to totally seal arcing and sparking devices
• Typical use in lighting controls and sealed switches
Used in Zones 21, and 22
Used in Zones 2
Good for normal operation
Used in zones 22
REQUIREMENTS:
• Arcing and sparking devices totally immersed by epoxy or other resin
• IEC approved non-loosening connectors
• Controls internal and external temperatures
CHART 4 — IEC vs NEC®/CEC TEMPERATURE CLASSIFICATION COMPARISON
Max. Surface
Temp. (°C)
85
100
IEC Classification
T6
T5
North American Classification
T6
120
135
160
165
180
200
T4
T5
T4A
215
230
260
280
T3
T4
T3C
T3B
T3A
T3
T2D
T2C
T2B
T2A
300
450
T2
T1
T2
CHART 11 — ATEX Equipment Category
The ATEX directive adds “The Equipment Category” to the marking which indicates the level of protection which correlates back to the manufacturers quality assurance
requirements as shown on this chart.
Equipment Category and
Level of Protection
Equipment Group
Presence or Duration of
Explosive Atmosphere
M1 - Very high level of protection
T1
I - Mines
Flammable Substances
Continuos Presence
NON-SPARKING “n”
Correlation with
Hazardous Areas
•
•
•
•
•
•
Methane, Combustible Dust
M2 - High level of protection
CHART 5 — Groups and subgroups classification — IEC
Groups
Group I
1 - Very high level of protection
Subgroups
Typical Substance
Application/Definition
I
Methane
Electrical Equipment for use in mines
susceptible to firedamp
(Not applicable to ATX Series Products)
IIA
Propane
IIB
Ethylene
IIC
Hydrogen
IIIA
Combustible flyings
IIIB
Non-conductive dust
IIIC
Conductive dust
II - Surface
ia ZONE 0
ib ZONE 1
ic ZONE 2
Incapable of releasing enough energy to cause an explosion
Typical use in communication equipment
REQUIREMENTS:
• Install in safe areas (non IS), or in an approved “d” enclosure
• Energy limiting barriers
• Transmits signal from hazardous area (IS)
• Prevents energy release
• Ensure isolation of circuits between IS and non IS areas
Conditions of Operation
Requires two independent means of protection or
remains safe when two different malfunctions occur
ZONE 1
Location of arcing has “d” protection (flameproof)
Connection terminals have “e” protection (increased safety)
Typical use in switches, lighting, controls, plugs and receptacles/sockets
Items such as power outlets, switches, some lighting, etc., cannot be protected by “e” mode only. In this case “d” and “e” are combined.
REQUIREMENTS:
• Area where arc can be produced is “d” or flameproof in a restricted volume enclosure - often contact blocks and switches
• Area with connection terminals is “e” or increased safety
• Controls internal and external temperatures
UNDERSTANDING NEC /CEC MARKINGS
CHART 3 — AREA CLASSIFICATION—IEC vs NEC®/CEC (CLASS/DIVISION/GROUP)
Subdivision
“e”
®
IEC/CENELEC
Equipment Level
Protection:
Ga for zone 0
Gb for zone 1
Gc for zone 2
Temperature Class
* See “Chart 11 — ATEX Equipment Category” below.
Division 2
Inflammable Material
Gas Group (acetylene &
hydrogen)
Protection Method
(intrinsic safety)
•
•
•
•
Ga
®
Zone 1 / zONE 21
ZONE 1
High impact resistant enclosures—FRP, GRP, sheet steel/aluminum, stainless steel
Enclosure will not hold static charge
Maintain minimum of IP 54 ingress protection
Apparatus non arcing/sparking
Typical use in terminal enclosures
UNDERSTANDING ATEX MARKINGS (Directive 94/9/EC) *
Zone in which an explosive mixture of dust is not likely
to occur in normal operation, and if it occurs will only
exist for a short time (leaks or maintenance).
Zone in which an explosive mixture of dust is likely to
occur during normal operation.
•
•
•
•
•
•
®
• • •
ZONE 0 / zONE 20
ZONE 1
Contain internal explosion
Control external temperature of enclosure
Similar to NEC® explosionproof
Usually cast enclosure
Typical use in lighting and motor starters
REQUIREMENTS:
• Internal explosion cannot be transmitted outside enclosure
• External temperature of enclosure below ignition temperature of surrounding gases
• Cable fittings must have 5 threads engaged
• Internal and external ground screw
Group II = Surface Equipment
Group I = Mines
Zone in which an explosive mixture is not likely to occur
in normal operation, and if it occurs will only exist for a
short time (leaks or maintenance).
Zone in which an explosive mixture of gas, vapor or mist
is likely to occur during normal operation.
Zone in which an explosive mixture of dust is continuously present.
FLAMEPROOF “d”
‡
Explosive Atmosphere May Accidentally Be Present
10-1000 hours/year
Zone in which an explosive mixture of gas, vapor or mist
is continuously present.
Ex
ZONE 2
Explosive Atmosphere Is Often Present
>1000 hours/year
CHART 14 — IEC Protection Techniques for Hazardous Areas
Zone 0 (Gas etc.)
Zone 20 (Dust)
Continuous Presence
2 - High level of protection
Likely to Occur
3 - Normal level of protection
Unlikely to Occur
G - Gas, Vapors
D - Dust
ZONE 2
Enclosure restricts ingress of hazardous gases
nA=non sparking construction
nR=restricted breathing
nC=hermetically sealed, non incendive
Typical use in lighting fixtures
REQUIREMENTS:
• Equipment has no normally arcing parts
• Thermal effects incapable of ignition
• nA=non sparking
• nR=restricted breathing
• nC=hermetically sealed non incendive
Zone 1 (Gas etc.)
Zone 21 (Dust)
Zone 2 (Gas etc.)
Zone 22 (Dust)
OIL IMMERSION “o”
Group II
CHART 12 — Understanding the Ingress Protection System
The IEC IP classification system designates the degree of protection provided by an enclosure against impact and/or water or dust penetration
(ingress). It has two numbers; first—protection against solid objects, second protection against liquid.
IP
Electrical equipment for use in places
with an explosive gas atmosphere
EXAMPLE: IP 54
1st Figure: protection against solid bodies
Group III (new)
IP
ZONE 1
2nd Figure: protection against liquids
TESTS
IP
REQUIREMENTS:
• Arcing and sparking devices totally immersed by oil
• IEC approved non-loosening connectors
• Controls internal and external temperatures
TESTS
Electrical equipment for use in places
with an explosive dust atmosphere
CHART 6 — Examples of IEC zone classification SITUATIONS
ZONE 0
• ZONE 1
• Oil totally seals arcing and sparking devices
• Typical use in hazardous rated transformers and switches
ZONE 2
0
No protection
0
No protection
1
Protected against solid bodies larger than 50mm (e.g. accidental contact with the hand)
1
Protected against vertically-falling drops of water
(condensation)
2
Protected against solid bodies larger than 12.5mm (e.g. finger of the hand)
2
Protected against drops of water falling at up to 15˚
from the vertical
3
Protected against solid bodies larger than 2.5mm (tools, wires)
3
Protected against drops of rainwater at up to 60˚ from
the vertical
PRESSURIZED APPARATUS “p”
• ZONE 1
• Expels ignitable vapor/gas
• Maintains positive enclosure pressure
NON HAZARDOUS ZONE
EXAMPLE 1
CONDITIONS:
 All manual ventilation
 Zone 0 area
 Zone 1 area
 Non hazardous area
• Open air mixing tank
• No mechanical ventilation
• Products stored in work area
REQUIREMENTS:
• Install in safe areas (non IS), or in an approved “d” enclosure
• Energy limiting barriers
• Transmits signal from hazardous area (IS)
• Prevents energy release
• Ensure isolation of circuits between IS and non IS areas
POWDER FILLING “q”
4
Protection against solid bodies larger than 1mm (fine tools, small wires)
4
Protected against projections of water from all directions
5
Protected against dust (no harmful deposit)
5
Protected against jets of water from all directions
6
Completely protected against dust
6
Completely protected against jets of water of similar
force to heavy seas
• ZONE 1
• Finely ground powder to totally seal arcing and sparking devices
• Typical use in lighting, controls and sealed switches
EXAMPLE 2
CONDITIONS:
 Hood over tank
 Zone 0 area
 Zone 1 area
 Zone 2 area
 Non hazardous area
 Mechanical ventilation
 Stored products separated from work area
REQUIREMENTS:
• Arcing and sparking devices totally immersed by finely ground powder
• IEC approved non-loosening connectors
• Controls internal and external temperatures
CHART 15 — IEC Protection Techniques for Areas With Combustible Dust
7
EXAMPLE 3
CONDITIONS:
 Tank closed
 Mechanical ventilation
 Zone 0
 Zone 2
 Non hazardous area
• Operations control outside zones
INTRINSIC SAFETY “iD”
Protected against the effects of temporary immersion
•
•
•
•
•
Protected against effects of prolonged immersion under
specified conditions
8
REQUIREMENTS:
• Install in safe areas (non IS), or in an approved “d” enclosure
• Energy limiting barriers
• Transmits signal from hazardous area (IS)
• Prevents energy release
• Ensure isolation of circuits between IS and non IS areas
CHART 13 — Approximate Conversion of NEMA Enclosure Type Ratings to IEC 60529 Enclosure Classification Designations (IP)
(Cannot be Used to Convert IEC classification Designations to NEMA Type Ratings or vice versa)
NEMA Enclosure Type
IP First
Character
1
CHART 7 — Examples of NEC®/CEC CLASS I, DIVISION 1 and 2 SITUATIONS
CLASS I, DIVISION 1
CLASS I, DIVISION 1 AND 2
NON CLASSIFIED
EXAMPLE 1
CONDITIONS:
 Class I, Division 1 hazard exists during normal operation conditions
• Open air mixing tank
• Products stored in work area
 Area classified based on properties of vapors present
 Electrical equipment must use approved Div. 1 NEC® protection techniques and wiring methods
EXAMPLE 2
CONDITIONS:
 Division 2 area can exist where vapors are normally in closed system or containers
 Division 1 and 2 areas separated by barrier or space (transition zone)
• Hazardous areas properly documented
• Div. 2 must use approved NEC® wiring methods and products
 Stored products outside Div. 1 work area
 Non hazardous area
2
3, 3X, 3S, 3SX
3R. 3RX
4, 4X
5
6
6P
12, 12K, 13
IP Second
Character
IP0_
IP_0
IP1_
IP_1
IP2_
IP_2
IP3_
IP_3
IP4_
IP_4
IP5_
IP_5
IP6_
IP_6
ENCAPSULATION “mD”
•
•
•
•
PRESSURIZATION “pD”
• ZONE 21, 22
• Expels ignitable vapor/gas
• Maintains positive enclosure pressure
REQUIREMENTS:
• Install in safe areas (non IS), or in an approved “d” enclosure
• Energy limiting barriers
• Transmits signal from hazardous area (IS)
• Prevents energy release
• Ensure isolation of circuits between IS and non IS areas
IP_8
EXAMPLE 3
B
A
B
A
B
A
B
A
B
A
B
A
B
A
B
A
PROTECTION BY ENCLOSURES “tD”
B
•
•
•
•
•
•
•
A = A shaded block in the “A” column indicates that the NEMA Enclosure Type exceeds the requirements for the respective IEC 60529 IP First Character Designation. The IP First Character Designation is the protection against access to hazardous parts and solid foreign objects.
CONDITIONS:
 Closed tank and piping confines Div. 1
 Yellow area qualifies as Div. 2
 Stored products not present
 Purged/pressurized control room qualifies as “non hazardous” is sealed off from Div. 2 area
 Electrical equipment in Div. 2 must use approved Div. 2 protection techniques and products
B = A shaded block in the “B” column indicates that the NEMA Enclosure Type exceeds the requirements for the respective IEC 60529 IP Second Character Designation. The IP Second Character Designation is the protection against the ingress of water.
Example of Table Use: An IEC IP 45 Enclosure Rating is specified. What NEMA Type Enclosures meet and exceed the IP 45 rating?
Glossary
Glossary
Equipment listed/marked for:
Use—as Noted
NEC® Class I, Div. 1
OK for use in NEC® Class I, Zone 1 and 2
NEC® Class I, Div. 2
OK for use in NEC® Class I, Zone 2
NEC® Class I, Zone 1
NOT OK for use in NEC® Class I, Div. 1
NEC® Class I, Zone 2
OK for use in NEC® Class I, Div. 2
NEC® AEx
OK for NEC® Zone 0, 1, 2 as marked
®
NEC AEx
NOT suitable for NEC Class I, Div. 1
®
NEC AEx
OK for use in NEC Class I, Div. 2
IEC Zone 1
NOT suitable for any NEC area
IEC Zone 2
NOT suitable for any NEC® area
IEC Ex or CENELEC EEx
NOT suitable for any NEC® area
®
®
AEx
Symbol designates equipment built to NEC standards for use in NEC Zone designated areas. Such products are not suitable for use in ATEX or IEC Ex applications.
ATEX
ATmosphères EXplosibles – Organizations in the EU where ‘explosion risk’ exists, must use the guidelines for protecting the employees of the
companies. Manufacturers who apply its provisions and affix the CE marking are able to sell their equipment anywhere in EU without any further
requirements being applied with respect to the risks covered being applied.
1.800.621.1506
www.egseg.com
®
Ex
Designation for hazardous location equipment complying to IEC and ATEX standards.
Flameproof
An IEC or European term using “containment” protection. Similar to, but not exactly the same as US “explosionproof”.
Group
Class I: Term used in NEC® to define a collection of gases with similar physical properties such as maximum explosion pressure. Class II: Term used in NEC® to define a collection of hazardous dusts with similar physical characteristics such as ignition temperature as well as
attributes such as blanketing effect on equipment.
Class III: There are no Group listings.
CEC
Canadian Electric Code.
CENELEC
European Committee for Electrical Standardization. CENELEC develops electrotechnical standards that are adopted as Euronorms by the EU for electrical
and electronic goods and services. It is comprised of a group of 31 European countries and 11 affiliated countries that have CENELEC standards based on
the parallel working IEC/CENELEC.
Hazardous Location
Exists when a manufacturing, storage or handling process provides a fuel, consisting of a flammable gas, combustible dust, combustible flying or
fiber, or some combination of these three elements; and these flammable components can be mixed with enough oxygen from the ambient air to form
an explosive atmosphere between the Lower Explosive or Flammable Limit (LEL/LFL) and the Upper Explosive or Flammable Limit (UEL/UFL).
Class I
Term used in NEC® to describe locations in which flammable gases or vapors are or may be present in the air in quantities sufficient to produce
explosive or ignitable mixtures.
IEC
International Electrotechnical Commission - International Standards and conformity assessment for all electrical, electronic and related technologies.
Class II
Term used in NEC® to describe locations that are hazardous because of the presence of combustible dust.
IECEx
Class III
Term used in NEC to describe locations that are hazardous because of the presence of easily ignitable fibers or flyings but in which such fibers or
flyings are not likely to be in suspension in the air.
International Electrotechnical Commission Explosive Atmospheres - An IECEx Scheme provides a means for manufacturers of EX equipment to obtain
Ex certificates of conformity that will be accepted at national level in all participating countries.
NEC ®
National Electric Code - Governs the installation of electrical conductors, equipment, and raceways.
Subdivision
Zone system grouping of various gas/vapors roughly equal to NEC® “Group”.
UL
Underwriters Laboratories - A US testing and certification organization.
Zone
Defines conditions under which explosive gases are present in an area. Zones are similar to divisions, but are generally based on length of time hazardous material may be present.
®
EGS Electrical Group
9377 W. Higgins Road
Rosemont, IL 60018
®
tD A21 Procedure A for ZONE 21
tD B21 Procedure B for ZONE 21
High impact resistant enclosures—FRP, GRP, sheet steel/aluminum, stainless steel
Enclosure will not hold static charge
Maintain minimum of IP 54 ingress protection
Apparatus non arcing/sparking
Typical use in terminal enclosures
REQUIREMENTS:
• Use IEC approved non-loosening type enclosures
• Control internal and external temperature
Referencing the first character, 4, in the IP rating and the row designated “IP4_” in the left most column in the table; the blocks in Column “A” for NEMA Types 3, 3X, 3S, 3SX,
3R, 3RX 4, 4X, 5, 6, 6P, 12, 12K and 13 are shaded. These NEMA ratings meet and exceed the IEC protection requirements against access to hazardous parts and solid foreign
objects.
CHART 8 — Simplified…Where to Use
maD for use in ZONE 20, 21, 22
mbD for use in ZONE 21, 22
Epoxy or other resin to totally seal arcing and sparking devices
Typical use in lighting, controls and sealed switches
REQUIREMENTS:
• Arcing and sparking devices totally immersed by epoxy or other resin
• IEC approved non-loosening connectors
• Controls internal and external temperatures
IP_7
A
iaD for use in ZONE 20, 21, 22
iaD for use in ZONE 21, 22
(Ex ibD) associated electrical apparatus - installation in the safe areas
Incapable of releasing enough energy to cause an explosion
Typical use in communication equipment
®
CSA
Canadian Standard Association - Provider of product testing & certification services for US, Canada and countries worldwide, for electrical, plumbing, gas & mechanical products.
Division 1
Term used in NEC® to describe the condition in which the hazard can be present during normal conditions.
Division 2
Term used in NEC® to describe the condition in which the hazard is present only under abnormal conditions.
Canada
Asia/Pacific
Middle East
888.765.2226
65.6891.7600
971.4.8838.831
Mexico
China
Europe
52.55.5809.5070
86.21.5426.0668
33.1.4817.8502
South America
Nutsteel Indústria Metalúrgica Ltda.
São Paulo/SP – Brazil
55.11.2122.5777
Macaé/RJ – Brazil
55.22.2770.4686
Camaçari/BA – Brazil
55.71.3623.2028