Minimum Clearances And Cable Routing For Use In Hazardous Areas - Siemens SIMATIC ET 200SP HA System Manual

Plant planning
4.5 Minimum clearances
4.5.2

Minimum clearances and cable routing for use in hazardous areas

General information
Physical isolation of non-Ex signals from Ex signals corresponds to the requirements with regard
to the configuration of explosion-protected automation technology.
Maintain safe distances - Minimum thread length
The distance between two points is called the thread length. These clearances are marked with
red arrows as an example in the following figure.
Due to the mechanical setup of the I/O station, a minimum thread length of 50 mm is maintained
between connections with safe functional extra-low voltage and intrinsically safe connections.
Ensure the following:
• The minimum thread length is maintained when wiring between intrinsically safe and non-
intrinsically safe connections.
• The minimum thread length is maintained between conductive parts from Ex to non-Ex I/O
modules.
• The intrinsically safe cables are laid separately from the non-intrinsically safe cables.
Recommendation: Lay the cables in separate cable ducts. Routing in shared cable ducts is not
recommended (observe thread length).
Wiring via connection elements
The following applies to the power supply:
• Voltage for the Ex module group is supplied by the Ex power module.
For supply of the Ex power module, connect a power supply (SELV/PELV) to the X80 plug.
• Voltage for the Ex I/O Modules is supplied from the Ex power module via the power bus.
The Ex process lines can be led directly from the process terminals of the Ex BaseUnit to the
equipment.
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Modules for devices in a hazardous area
System Manual, 04/2021, A5E50165138-AA