24 V Product Group Xr300M Poe - Siemens SCALANCE X308-2M Operating Instructions Manual

6.4.1.6

24 V product group XR300M PoE

24 V safety extra-low voltage (SELV)
Safety extra low voltage
The equipment is designed for operation with a directly connected safety extra-low voltage
(SELV). (This does not apply to 100 V to 240 V devices.)
The maximum current via the 24 V terminals is 8 A. You should therefore include a fuse
that trips at a current higher than 8 A. The fuse must meet the following requirements:
• Suitable for DC (min. 60 V / max. 8 A)
• Breaking current at least 10 kA
• UL/CSA listed (UL 248-1 / CSA 22.2 No.
• Classes R, J, L, T or CC
As an alternative, the following requirements:
• Suitable for DC (min. 60 V / max. 8 A)
• Breaking current at least 10 kA
• Approved in compliance with IEC 60127-1 / EN 60127-1
• Breaking characteristics: B or C for a circuit breaker or slow-blow fuse
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. A suitable device is, for
example, the Dehn Blitzductor VT AD 24 V type no. 918 402 or comparable protective
element.
Vendor: DEHN+SÖHNE GmbH+Co.KG, Postfach 1640, D-92306 Neumarkt, Germany
Connecting to the power supply (SELV)
● The power supply is connected using a 4-pin plug-in terminal block.
● The power supply can be connected redundantly. Both inputs are isolated. There is no
● The power supply is connected over a high resistance with the enclosure to allow an
SCALANCE X-300
Operating Instructions, 02/2012, A5E01113043-12
WARNING
CAUTION
distribution of load. When a redundant power supply is used, the power supply unit with
the higher output voltage supplies the IE Switch X-300 alone.
ungrounded set up. The two power inputs are non-floating.
Connecting
6.4 Power supply
133