Running Cables Outside Buildings - Siemens SIMATIC S5-90U System Manual

Installation Guidelines
3.5.2

Running Cables Outside Buildings

Run lines outside buildings where possible in metal cable supports. Connect the abutting surfaces of
the cable supports galvanically with each other and ground the cable supports.
When you run cables outdoors, you must observe the regulations governing lightning protection and
grounding. Note the general guidelines:
Lightning Protection
If cables and lines for SIMATIC S5 devices are to be run outside buildings, you must take measures
to ensure internal and external lightning protection.
Outside buildings run your cables
either
- In metal conduits grounded at both ends
or
- In steel-reinforced concrete cable channels
Protect signal lines from overvoltage by using:
• Varistors
or
• Lightning arresters filled with inert gas
Install these protective elements at the point where the cable enters the building.
Note
Lightning protection measures always require an individual assessment of the entire
system. If you have any questions, please consult your local Siemens office or any
company specializing in lightning protection.
Grounding
Make certain that you have sufficient equipotential bonding between the devices.
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S5-90U/S5-95U
EWA 4NEB 812 6115-02b