Installation; Mains Voltage - Siemens CPU 313C Hardware And Installation Manual

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The following table shows you what to watch with respect to the mains voltage.
Table 12-2
For stationary systems or systems without
all-pole mains disconnect switch
For load power supplies, power supply
modules
For all circuits of the S7-300
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The table below shows what you must observe in connection with the 24 VDC
power supply.
Table 12-3
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Buildings
24 VDC power supply cables,
signal cables
24 VDC Power Supply
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The table below shows how you must protect your system against electrical
interference or faults.
Table 12-4
All plants or system with an S7-300

installation

Supply/signal/bus cables
Signal and bus cables
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can be found in the following Chapters.
12-2

Mains voltage

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Protection against external electrical interference
External lightning
protection
Internal lightning
protection
Safe (electrical) extra-low voltage isolation
Protection against external electrical interference
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S7-300 Automation System, Hardware and Installation: CPU 31xC and CPU 31x
LV 
Installation of a mains disconnect switch or
a fuse in the building installation system.
The set rated voltage range must
correspond to the local power supply
voltage.
Rated mains voltage fluctuation/deviation
must lie within the permitted tolerance (refer
to Technical Data of S7-300 modules).
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Install lightning protection
(e.g. lightning conductors).
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the plant or system is connected to a
protective conductor for the suppression of
electromagnetic interference.
The conductor routing and installation is
correct.
a cable/conductor break does not result in
undefined plant or system states.
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