ABB AC 900F, Mounting And Installation Instructions Manual

Page: 85 / 156

Section 6 Wiring Cable routing
M&I – AC 900F Controller 85
Cable routing
• Ensure proper cable routing during wiring.
• Sort the cables in different cable groups (power current cables, power supply
cables, signal cables and data cables).
• Make sure to lay signal and data cables separately from power current cables,
i.e. in separate conduits or cable bundles. The distance should be at least 20
cm.
• Signal and data cables should be installed close to earthed surfaces.
Cable shields
• Use only shielded data cables. The shield must be earthed on both sides. Make
sure that no compensating currents pass through the cable shield. A current-
carrying equipotential bonding line can be used for this purpose.
• If a cable shield is earthed on one side, it only provides protection against
capacitive coupling and low-frequency interference (50/60 Hz ripple voltage).
• Only use braided-shield cables. Foil shields exhibit low mechanical stability as
well as poor contact and HF properties.
• Only metallic or metal-coated connectors must be used for shielded data
cables.
• Use only shielded cables for analog signals. Earth the shield on one end only
for the transmission of small signals.
• Earth the cable shield using a clamp directly at the entry into the switch
cabinet. Guide the shield up to the module without any interruption.
• There must be a low-impedance connection between the PE bar and the shield
bar.