Equipotential Bonding - Siemens S5-155U System Manual

Routing of cables outside
buildings
Lightning protection

Equipotential bonding

System Manual
C79000-B8576-C199-03
Wiring of Programmable Controllers for EMC
Legend for the table
Lines can be laid in common bundles or cable ducts.
Lines must be laid in separate bundles or cable ducts (without
minimum clearance).
Lines within cabinets must be laid in separate bundles or cable
ducts; outside the cabinets but within buildings, they must be
laid over separate cable routes with a clearance of at least 10 cm.
Lines must be laid in separate bundles or cable ducts with a
clearance of at least 50 cm.
Outside buildings, lay the lines on metal cable trays if possible.
Provide the joints between cable trays with an electrical connection
and ground the cable trays.
When laying lines outside buildings, you must observe the valid
lightning protection and grounding measures. The following applies in
general:
Caution
Where cables and lines for SIMATIC S5 controllers are to be laid
outside buildings, you must apply measures for internal and
external lightning protection.
Outside the buildings, lay your lines either
• • in metal conduit grounded at both ends,
or
• • in concreted cable ducts with continuously connected
reinforcement.
Protect the signal lines from overvoltages by means of
• • varistors
or
• • inert gas-filled surge diverters.
Fit these protective devices at the cable entry into the building.
Note
Lightning protection measures always require an individual
assessment of the entire installation. For clarification, please
consult your Siemens regional office or a company specializing in
lightning protection.
Ensure adequate equipotential bonding between the connected
equipment (see Section 3.3.2).
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