A circuit “intrinsically safe” when, under
normal operating conditions and the event
of specific fault conditions, sparks ther-
mal effects can occur and cause the ignition
of certain explosive atmosphere. Each possi-
ble motion metallic parts that are not rig-
idly secured must considered., via cable lugs ferrules) the type
of terminal blocks used. Soldering alone is
not sufficient. First,
intrinsically safe circuits are separated at
least air space from non-intrinsi-
cally safe circuits. The insulation between these circuits
should withstand effective voltage at
least 500 VAC UAC where the total
of the effective voltages the related cir-
cuits. color used for this, the
color must light blue (similar RAL
5015).
Electrical equipment classified “ib” must
not ignite when current applied the fol-
lowing cases:
a)
During fault-free operation, with those
non-discreet faults present that result in
the most adverse condition
b)
During fault-free operation and with dis-
creet fault, plus those non-discreet faults
that result unfavorable conditions. separate intrinsically safe
circuits are considered, the air gap
between bare conductive parts the outer
connection parts must meet the following
requirements:
– least between the separate intrinsi-
cally safe circuits
– least from grounded parts, pos-
sible connection ground has not been
considered the safety analysis.
In accordance with 60079-14/
DIN VDE 0165-1, intrinsically safe circuits,
the ends stranded and fine-stranded con-
ductors must protected against splaying
(e.
The insulation between intrinsically safe
and non-intrinsically safe circuit has to
withstand effective voltage nom-
inal value (U) 1000 minimum of
1500 kV, whereby represents the total of
the effective voltages the intrinsically safe
and the non-intrinsically safe circuit.
Short circuit between different intrinsically
safe circuits could cause dangerous condi-
tions. The partition size must allow
for either 1.
Second, intrinsically safe circuits are housed
in separate enclosure.com
WAGO Rail-Mount Terminal Block Systems
Technical Information for Applications
Special Requirements
Equipment Protection Intrinsic Safety “i”
The European 60079-11 Standard Clas-
sification VDE 0170-7 contains special
requirements for the design and testing of
electrical equipment with “i” (intrinsic safety)
protection type for use hazardous areas.
At applied voltages, the intrinsically safe cir-
cuits electrical equipment protection
level “ic” shall not capable causing igni-
tion during undisturbed operation and under
the conditions specified this standard.
Continued
General Technical Information Electrical Equipment
Used Hazardous Areas
.wago.
A distinction made here between:
• intrinsically safe electrical equipment when
all circuits are intrinsically safe
• associated electrical equipment including
both intrinsically and non-intrinsically safe
circuits, and being designed such that the
non-intrinsically safe circuits cannot affect
the intrinsically safe ones.
WAGO recommends gas-tight tinned copper
ferrules tinned copper pin terminals when
connecting fine-stranded conductors ter-
minal blocks corrosive atmospheres. This accom-
plished several accepted methods.g.40
www. Third, intrinsically
safe terminal blocks are separated from
non-intrinsically safe terminal blocks by
either insulated partition grounded
metal partition.
Intrinsically safe electrical equipment and
intrinsically safe parts associated electri-
cal equipment are classified “ia”, “ib” “ic”
protection level.
The terminal blocks must identifiable, for
example their type designation, and the
following design requirements must also be
upheld:
Clearances and creepage distances between
bare conductive parts terminal blocks of
separate intrinsically safe circuits and
grounded floating conductive parts shall
be equal greater than the values given in
Table (see 672).
Electrical equipment classified “ia” must
not ignite when current applied the fol-
lowing cases:
a)
During fault-free operation, with those
non-discreet faults present that result in
the most adverse condition
b)
During fault-free operation and with dis-
creet fault, plus those non-discreet faults
that result unfavorable conditions
c)
During fault-free operation with two dis-
creet faults, plus those non-discreet faults
that result the most adverse conditions.
Terminal block marking must unique and
clearly visible.
No special approval required for terminal
blocks used simple electrical equipment
for “Ex protection type, they not con-
tain voltage source and precise information
is available concerning electrical data and
temperature rise performance.
Note also when using terminal blocks:
Terminal blocks used for intrinsically safe cir-
cuits must isolated from those used in
non-intrinsically safe circuits.5 less distance from the
sides the housing provide least
50 creepage distance between the
intrinsically and non-intrinsically safe circuits
in all directions
