6.7.1.2
Connecting the external 24 VDC power supply
24 V safety extra-low voltage (SELV)
WARNING
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. 248.1)
• 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
CAUTION
Damage to the device due to overvoltage
One of the tests used to attest the immunity of devices of the IE Switches X300 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 BVT AVD 24 article no. 918 422 or a comparable protective element.
Manufacturer: DEHN+SÖHNE GmbH+Co.KG, Postfach 1640, D92306 Neumarkt, Germany.
Do not operate the SCALANCE X-300 without suitable overvoltage protection.
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
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.
• The power supply is connected over a high resistance with the enclosure to allow an
ungrounded set up. The two power inputs are non-floating.
Connecting up
6.7 Power supply
SCALANCE XR-300M PoE
60
Compact Operating Instructions, 03/2022, A5E02661178-15
