The highest measured surface temperature
rise must not exceed K. The surrounding air
temperature, which must accounted for in
dimensioning, defined 40°C/104°F (devi-
ations are acceptable under some condi-
tions).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.
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
. 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.
This information given under Item the
EU Prototype Test Certificates, based on
which the terminal blocks have been
approved for Group and Group II.
This standard supplement 60079-0
and applies equipment parts thereof
that neither generate sparks arcing under
normal operating conditions, nor exhibit haz-
ardous temperatures.
• The use this component requires new
assessment notified certification
agency. When using
accessories, the installation instructions of
the manufacturer must observed.
This standard describes special measures,
which have observed obtain safety
degree according the “eb” (increased
safety) protection type.
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).
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.wago.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.36
www. 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.
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).
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.
Ex components such rail-mount terminal
blocks are covered Section 4.
• When installing the terminal blocks an
enclosure protection type “eb”
(increased safety) per 60079-7, the
clearances and creepage distances of
Table must observed.
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.
This breakdown based different gases/
materials exhibiting differing ignition power
levels parameters.
• The terminal blocks can used both in
Group and Group the standard
requirements are identical this case
