Ex components such rail-mount terminal
blocks are covered Section 4. When using
accessories, the installation instructions of
the manufacturer must observed.
This breakdown based different gases/
materials exhibiting differing ignition power
levels parameters. Low tem-
perature stability considered suffi-
cient when the insulation material can with-
stand 24-hour storage temperature of
−60°C (−76°F) without nullifying the type of
protection.
Temperature
Class
Maximum Surface
Temperature (°C)
T1 450
T2 300
T3 200
T4 135
T5 100
T6 85
Depending the maximum surface tem-
perature, electrical equipment Group are
classified temperature categories T6
for all protection types.2 “Terminal
Blocks for External Conductors”:
• The terminal blocks must installed an
enclosure meeting the requirements a
recognized protection type per 60079-0,
Section 60079-31.
This information given under Item the
EU Prototype Test Certificates, based on
which the terminal blocks have been
approved for Group and Group II.
• The use this component requires new
assessment notified certification
agency.wago. The surrounding air
temperature, which must accounted for in
dimensioning, defined 40°C/104°F (devi-
ations are acceptable under some condi-
tions).
EN 60079-0 also classifies electrical equip-
ment for use hazardous areas into two
groups:
Group I:
Electrical equipment for mines susceptible to
firedamp
Group II:
Electrical equipment for hazardous areas,
except for mines susceptible firedamp.
• The terminal blocks can used both in
Group and Group the standard
requirements are identical this case.com
WAGO Rail-Mount Terminal Block Systems
Technical Information for Applications
Thermal resistance the insulation material
must least 20°C (68°F) greater than the
highest operating temperature. Therefore, representa-
tive gases have been allocated these three
sub-groups:
• IIA Propane
• IIB Ethylene
• IIC Hydrogen
WAGO’s terminal blocks can used both
in Group and Group II.
• When installing the terminal blocks an
enclosure protection type “eb”
(increased safety) per 60079-7, the
clearances and creepage distances of
Table must observed.
This standard supplement 60079-0
and applies equipment parts thereof
that neither generate sparks arcing under
normal operating conditions, nor exhibit haz-
ardous temperatures.
This standard describes special measures,
which have observed obtain safety
degree according the “eb” (increased
safety) protection type.
Minimum Ignition Power Typical Gases:
Explosion Group IIA IIB IIC
Gas Methane Propane Ethylene Hydrogen
Ignition Power 280 250 16
Continued
General Technical Information Electrical Equipment
Used Hazardous Areas
.
As this broad application range encom-
passes large number potentially flamma-
ble gases, Group broken down into sub-
groups IIA, IIB and IIC.
The following are the most important design
requirements for terminal blocks for external
supply conductors electrical equipment:
These must:
• sufficiently large permit reliable con-
nection external supply conductors with
cross section least the size required
by the nominal current the equipment
• protected against self-loosening and
designed such that the supply conductors
cannot slip out their clamping units
• designed such that adequate contact
pressure ensured without damaging the
conductors
• designed such that their contact pres-
sure does not change with temperature
cycling
• equipped with spring connecting link
for the connection stranded conductors
• designed allow secure connec-
tion smaller conductors for terminal
blocks mm² (12 AWG).
Terminal blocks for “eb” (increased safety)
protection type are generally assigned to
temperature category When rail-mount
terminal blocks are used equipment of
temperature categories T5, ensure that
the highest temperature the insulating
parts does not exceed 85°C (185°F).
The highest measured surface temperature
rise must not exceed K.36
www.
Special Requirements
“Increased Safety e”
The European 60079-7 Standard VDE
0170-6 Classification contains special
requirements for the design and testing of
electrical equipment with “eb” (increased
safety) protection type for use hazardous
areas
