Siemens SCALANCE X-200 Series Compact Operating Instructions page 82

Connection
5.1 Power supply
Note
Because the SCALANCE X204 IRT PRO, the SCALANCE X202-2P IRT PRO and the
SCALANCE X201-3P IRT PRO do not have a redundant power supply, the power supply
must be connected to L1 and N1.
IE Switches X-200 are designed for operation with SELV (Safety Extra Low Voltage). This
means that only safety extra-low voltages (SELV) complying with IEC950/EN60950/
VDE0805 can be connected to the power supply terminals.
Measures must be taken to prevent transient overvoltages of more than 40% of the rated
voltage. This is the case if the devices are operated exclusively with SELV (Safety Extra
Low Voltage).
Exception:
SCALANCE X204 IRT PRO, X202-2P IRT PRO and X201-3P IRT PRO:
When fused as described above
The power supply unit for the IE Switch X-200 power supply must meet NEC Class 2, as
described by the National Electrical Code(r) (ANSI/NFPA 70).
The power of all connected power supply units must total the equivalent of a power source
with limited power (LPS limited power source).
If the device is connected to a redundant power supply (two separate power supplies), both
must meet these requirements.
The signaling contact can be subjected to a maximum load of 100 mA (safety extra-low
voltage (SELV), 24 V DC).
Never operate an IE Switch X-200 with AC voltage or DC voltage higher than 32 V DC.
CAUTION
If IE Switches X-200 are supplied over long 24 V power supply lines or networks, measures
are necessary to prevent interference by strong electromagnetic pulses on the supply lines.
These can result, for example, due to lightning or switching of large inductive loads.
One of the tests used to attest the immunity of devices of the IE Switches X-200 to
electromagnetic interference was the "surge immunity test" according to EN61000-4-5. This
test requires overvoltage protection for the power supply lines. A suitable device is, for
example, the Dehn Blitzductor VT AD 24 V type no. 918 402 or comparable protective
element.
Manufacturer: DEHN+SÖHNE GmbH+Co.KG, Hans-Dehn-Str.1, Postfach 1640, D-92306
Neumarkt, Germany.
82
WARNING
Compact Operating Instructions, 12/2010, A5E00813159-11
SCALANCE X-200