Siemens SIMATIC NET SCALANCE XC-300 Operating Instructions Manual page 59

Damage to the device due to overvoltage
The connector of the external power supply is not protected against strong electromagnetic
pulses that can, for example, result from lightning strikes or switching large loads.
One of the tests used to attest the immunity of the device to electromagnetic interference is the
"surge immunity test" according to EN 61000-4-5. This test requires overvoltage protection for
the power supply lines. A suitable device is, for example, the Dehn Blitzductor BVT AVD 24,
article number 918 422 or a comparable protective element.
Manufacturer: DEHN+SOEHNE GmbH+Co. KG, Hans-Dehn-Str.1, Postfach 1640, D92306
Neumarkt, Germany
Operate the device with suitable overvoltage protection.
Note
The device can be disconnected from the power supply by pulling off the terminal block.
Information on the power supply
• The "L1" and "L2" LEDs indicate the current range of the power supply, see the section "LEDs
"L1" and "L2" (Page 35)".
• You can use two 2-pin terminal blocks or one 4-pin terminal block (spring-loaded terminal)
to connect the power supply.
If you use two 2-pin terminal blocks, you can disconnect only the affected power supply from
the device to perform repairs.
Two 2-pin terminal blocks are included in the scope of delivery of the device. You can order
2- and 4-pin terminal blocks as spare parts, see section "Spare parts".
• 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 device 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.
• Note the wiring rules (Page 58).
• The power supply must meet the requirements in relation to RF radiation according to IEC
61000-4-3/NAMUR NE21 so that the overall system meets these requirements; see also "RF
radiation according to NAMUR NE21 (Page 87)".
SCALANCE XC-300
Operating Instructions, 10/2022, C79000-G8976-C584-01
CAUTION
Connecting up
6.3 Power supply
59