Siemens SINAMICS S120 Equipment Manual page 319

Two-tier configuration
Figure 14-4
The distance between the two module rows depends on the wiring and cable cross-section.
For modules with a width of between 50 and 100 mm, the distance between the upper and
lower module row must be at least 300 mm.
For modules with a width of between 150 and 300 mm, the distance between the upper and
lower module row must be at least 500 mm (see Cooling).
Booksize cold-plate power units
Manual, (GH4), 03.2007, 6SL3097-2AJ00-0BP4
Example of a multi-tier configuration with components between 200 and 300 mm wide
14.4 Arrangement of Components and Equipment
Cabinet Design and EMC
319