Siemens SINAMICS S120 Equipment Manual page 306

Cabinet Configuration and EMC Booksize
8.3 24 V DC supply voltage
Figure 8-2
The following standards should be carefully observed when selecting the cable protection
circuit-breakers:
EN 61800-5-1, EN 60204-1, IEC 60364-5-52, IEC 60287-1 to -3, EN 60228 and UL 508C.
The following conditions for the conductors/cables should be used as basis:
• Ambient temperature 55 °C
• Limit conductor temperature ≥ 75 °C for operation with the rated load current
• Cable length max.:
Further, the conductors/cables should be routed so that
• max. 1 conductor pair, bundled and
• the 24 V conductors should be separately routed away from other cables and conductors
8-10
Example, 24 V DC fusing/protection
– 10 m for the supply cables
– 30 m for signal lines
that could conduct the operating current.
Equipment Manual for Booksize Power Units
Equipment Manual, (GH2), 03/2006 Edition, 6SL3097-2AC00-0BP3