Siemens SIMATIC ET 200SP System Manual page 33

Selection criteria for the BaseUnit
The figure below shows the criteria you use to select the appropriate BaseUnit:
Form separate potential groups on the infeed bus for single-phase (L, N, PE) and three-
phase (L1, L2, L3, PE) operation.
Use end retainers
In the case of a vertical mounting position, use an end retainer at both ends of the ET 200SP
station (8WA1808).
Motor starter
System Manual, 04/2016, A5E35582704002A/RS-AA/001
Application planning
3.5 Selecting the BaseUnit
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