Siemens SIMATIC ET 200S Manual page 107

Line voltage
The following table tells you what you have to do with regard to the line voltage.
Permanently installed plants or systems
without all-pole line disconnect switches
Load power supplies, power supply
modules
All circuits of the ET 200S distributed I/O
system
24 VDC supply
The following table tells you what you have to do with regard to the 24 VDC supply.
Buildings
24 VDC supply lines,
signal lines
24 VDC supply
Protection against outside electrical influences
The following table tells you what to do to provide protection against electrical
influences or faults.
All plants or systems in
which the ET 200S is
integrated
Supply, signal, and bus
lines
Signal and bus lines
ET 200S Distributed I/O System
EWA-4NEB780602402-09
With ...
With ...
Outdoor lightning
protection
Indoor lightning
protection
Safe (electrical) isolation of extra-low voltage
With ...
The plant or system is connected to a protective
conductor for diverting electromagnetic interference.
The wiring arrangement and installation are correct.
Any break of a line or conductor does not result in
undefined states of the plant or system.
Requirements
There must be a line disconnect switch or a
fuse in the building installation system.
The set rated voltage range must
correspond to the local line voltage.
Any fluctuation/deviation in the line voltage
from the rated value must be within the
permitted tolerances (see Section 7.4)
Pay attention to ...
Take lightning protection
precautions
(for example, lightning
conductors)
You must ensure that...
Wiring and Fitting
5-3