Siemens S5-100U User Manual page 62

S5-100U
Wiring Arrangement outside a Cabinet
• Install cables on a metal cable bearer when cabinets are physically apart but within the same
building. Galvanically connect the cable bearer joints. The joints should be grounded at intervals
of about 20 to 30 meters (65 to 98 feet).
• Always use shielded analog signal cables .
• Install the following cables on the same cable raceways (cable routes, cable ducts, cable
channels, and cable conduits):
- Unshielded digital cables 60 V
- Shielded data cables and shielded analog cables, including the ET 200 bus cable
- Shielded signal cables of up to 230 V
• Install cables having voltages >230 V in separate wiring channels (routes, conduits).
Wiring Arrangement outside a Building
Make certain that cables installed outside buildings adhere to the regulations regarding lightning and
grounding.
• Lightning
When installing cables outside a building, use one of the following methods:
- Use corrosion-resistant steel conduit that is well grounded.
- Use nonmetallic conduit that is encased in steel-reinforced concrete. The reinforcing steel
should be made electrically continuous and should be well grounded.
• Grounding
- Make certain that you have sufficient equipotential bonding between the devices.
- Install an equipotential bonding cable that has an impedance 10% of the shield impedance
of the cables.
Tips for Cable Installations
• Do not install signal cables directly parallel to power cables.
• Install electromagnetically sensitive cables at least one meter (3.3 feet) away from any source of
interference (contactor, transformer, motor, arc welder, etc.).
• Make certain that you bundle the cables together if two control components are joined together
by several signal cables.
• Install signal cables and the corresponding equipotential bonding cables bundled together on the
shortest route possible.
• Install individual cables that carry the same type of signal (outgoing and return cables and power
supply cables) bundled together. Twist the cables, if needed.
• Route the cables against the chassis-grounded surfaces where possible.
• Avoid using terminal lugs to extend cables.
• Route power cables and signal cables through separate cable ducts and switch boxes.
• Use surface-type contact for the shields.
3-30
Installation Guidelines
EWA 4NEB 812 6120-02