Mounting and Installation
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137189 / 8146619300
2016-11-10·BA00·III·en·06
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Terminal Boxes
Series 8146/1, Series 8146/2
Distance between the connecting units for intrinsically safe and non-intrinsically safe circuits
Mount partitions used to separate connection terminals at least 1.5 mm from the enclosure
walls, or alternatively ensure a minimum distance of 50 mm between the uncoated
conducting parts of the connection terminals (when measured in any direction around
the partition)
Make sure that metallic partitions
• are at least 0.45 mm thick
• are earthed
• are sufficiently strong and rigid
• have sufficient current carrying capacity.
Make sure that non-metallic, insulating partitions
• are at least 0.9 mm thick
• have an appropriate comparative tracking index (CTI)
• are reinforced to prevent deformation.
When using fuses > 4 A, implement additional design measures to prevent impermissible
heat-up at the terminals of the intrinsically safe circuits.
Covers for combinations of non-intrinsically safe and intrinsically safe circuits
Equip all live parts which are not acc. to "Ex i" protection with an inner cover which meets
at least the degree of protection IP30 when the equipment is open.
Intrinsically safe circuits
In intrinsically safe circuits, use only insulated cables and conductors with a test voltage
of at least 500 V AC and a minimum quality of H05.
Calculate the insulation test voltage for the insulation and separation of terminals and
conductors from the sum of the rated operational voltages of intrinsically safe and
non-intrinsically safe circuits.
• In case of "intrinsically safe to earth", there is a minimum rated insulation voltage value
of 500 V (otherwise, double the value of the rated operational voltage of intrinsically
safe circuits).
• In the case of "intrinsically safe to non-intrinsically safe", there is a minimum rated
insulation voltage value of 1500 V (otherwise, double the rated operational voltage plus
1000 V).
Clearance and creepage distances of intrinsically safe components
Make sure that the creepage distances and clearances between the uncoated,
conductive parts of connection terminals of separated, intrinsically safe circuits to earthed
or potential-free, conductive parts is equal or greater than the values of EN IEC 60079-11,
Table 5.
For separated, intrinsically safe electric circuits, set up a safe distance between the
uncoated, conductive parts of external connections, which meets the following
requirements:
• minimum 6 mm between the separated, intrinsically safe circuits
• minimum 3 mm to earthed parts if possible connection to earth has not been considered
in the safety analysis.
