Siemens Electrical Lean Switch - Manual (Page 30)

Ports and Displays
Industrial Ethernet
30 A5E00152007-03
! Warning
Industrial Ethernet ELS TP40M switches are designed for operation with 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.
The power supply unit to supply the ELS TP40M must comply with NEC Class 2
(voltage range 18 - 32 V, current requirement 150 mA).
Never connect the ELS to a.c. power supplies or d.c. power supplies greater than
32 V d.c.
Power Supply
The power supply is connected over a high resistance with the enclosure to allow
an ungrounded setup. The ELS TP40M device can also be grounded using the PE
screw terminal on the terminal block.