Siemens SIMATIC Distributed I/O ET 200eco PN Operating Instructions Manual page 29

Wiring
3.2 Operating ET 200eco PN on grounded mains
Definition: Grounded power supply
For grounded power supplies the neutral conductor of the supply system is grounded. A
short-circuit to ground of a live conductor, or of a grounded part of the system, trips the
protective devices.
Safe electrical separation (SELV in accordance with IEC 61131-2 or IEC 61010-2-201)
Load power supplies/power supply modules with 24 V DC output voltage require safe
electrical separation and voltage limiting (extra low voltage). Load power supplies/power
supply modules with 24 V DC output voltage are not connected to the protective conductor.
According to IEC 61131-2 and IEC 61010-2-201, this protection is referred to as SELV (Safety
Extra Low Voltage).
The wiring of SELV circuits must be safely separated from the wiring of other circuits that are
not SELV, or the insulation of all conductors must be dimensioned for the higher voltage.
Grounded extra-low voltage (PELV in accordance with IEC 61131-2 or IEC 61010-2-201)
Load power supplies/power supply modules with grounded 24 V DC output voltage require
safe connection to the protective conductor and voltage limiting (extra low voltage).
According to IEC 61131-2 and IEC 61010-2-201, this protection is referred to as PELV
(Protective Extra Low Voltage).
Either the wiring of PELV circuits must be safely isolated from the wiring of other circuits that
are not PELV, or the insulation of all wires must be dimensioned for the higher voltage.
Components and protective measures
A number of components and protective measures are prescribed for plant installations. The
type of components and the degree to which the protective measures are mandatory depend
on which DIN VDE regulation applies to your system configuration. The following table refers
to the figure below.
Comparison ...
Disconnecting device for
controller, sensors, and
actuators
Short-circuit / overload
protection
Circuit breaker
30
Reference to fig­ DIN VDE 0100
ure
(1) ... Part 460:
"Grounding Main switch
concept for
ET 200eco PN"
(2) ... Part 725:
"Grounding Single-pole protection
concept for of circuits
ET 200eco PN"
... Part 430:
Protection of cables
and wires against
overcurrent
DIN EN 60204
... Part 1:
Disconnector
... Part 1:
With grounded secondary circuit:
Single-pole protection
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Operating Instructions, 06/2022, A5E01250250-AN
ET 200eco PN