Power Supply; 24 Vdc Power Supply; Safety Extra Low Voltage - Siemens SCALANCE X-300 Series Operating Instructions Manual

Connecting

6.6 Power supply

6.6 Power supply
6.6.1

24 VDC power supply

6.6.1.1

Safety extra low voltage

24 V safety extra-low voltage (SELV)
Operation only with safety-extra low voltage
● The IE Switch X-300 is designed for operation with safety extra-low voltage (SELV). This
● The power supply unit for the IE Switch X-300 power supply must meet NEC Class 2, as
● The power of all connected power supply units must total the equivalent of a power source
● If the device is connected to a redundant power supply (two separate power supplies), both
● The signaling contact can be subjected to a maximum load of 100 mA
● Never operate the device with AC voltage or DC voltage higher than 32 V DC.
Overvoltage protection for the power supply cables
If IE Switches X-300 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-300 to
electromagnetic interference is the "surge immunity test" according to EN61000-4-5. This test
requires overvoltage protection for the power supply lines (doe not apply to the X‑300EEC).
A suitable device is, for example, the Dehn Blitzductor BVT AVD 24 article no. 918 422 or a
comparable protective element.
The modular Blitzductor BXT ML4 BE 36, art. no. 920 336, with the corresponding basic part
BXT BAS, art. no. 920 300, is recommended for railway applications according to EN 50155
and EN 50121.
Manufacturer: DEHN+SÖHNE GmbH+Co.KG, Hans Dehn Str. 1, Postfach 1640, D - 92306
Neumarkt, Germany.
128
WARNING
means that only safety extra-low voltages (SELV) complying with IEC950/EN60950/
VDE0805 can be connected to the power supply terminals.
described by the National Electrical Code(r) (ANSI/NFPA 70).
with limited power (LPS limited power source).
power supplies must meet these requirements.
(safety extra low voltage (SELV), 24 V DC).
CAUTION
Operating Instructions, 11/2019, A5E01113043-24
SCALANCE X-300