Siemens Simatic ET 200S Operating Instructions Manual page 82

Wiring and assembly
5.1 General rules and regulations for operating the ET 200S
Line voltage
The following table identifies requirements to be observed for the line voltage.
Stationary plants or systems without all-pole line
voltage disconnect switch
load power supplies, power supply modules
All circuits of the ET 200S distributed I/O system
24 VDC supply
The following table identifies requirements you must observe for the 24 VDC supply.
Buildings
24 VDC power supply cables, signal
cables
24 VDC supply
Protection against external electrical influences
The table below shows how you must protect your system against electrical interference or
faults.
all plants or systems in which the ET 200S
is integrated,
power supply, signal, and bus cables
Signal and bus cables
See also
Mechanical and Climatic Ambient Conditions (Page 9-7)
5-2
With...
With ...
With ...
There must be a line voltage disconnect switch or
a fuse in the building installation.
The set rated voltage range must match the local
line voltage.
Any fluctuation/deviation of the line voltage from
the rated value must be within the permitted
tolerances
you need to observe ...
External lightning
protection
internal lightning
protection
Safe (electrical) isolation of extra-low voltage
Make sure that ...
the plant or system is connected to a protective
conductor for diverting electromagnetic interference.
the cable routing and installation is correct.
A cable or wire break must not lead to undefined states
in the plant or system.
Operating Instructions, 12/2005, A5E00515771-03
Requirements...
Take lightning protection
precautions
(for example, lightning protection
elements)
ET 200S