Siemens SIMATIC S7-400 Operating Instructions Manual page 30

Installation, connecting up, commissioning
3.1 Important notes on using the device
The device may only be operated in an environment with pollution degree 1 or 2 (see IEC
60664-1).
EXPLOSION HAZARD
The device must not be opened.
Power supply
The equipment is designed for operation with Safety Extra-Low Voltage (SELV) by a
Limited Power Source (LPS).
This means that only SELV / LPS complying with IEC 60950-1 / EN 60950-1 / VDE 0805-1
must be connected to the power supply terminals. The power supply unit for the equipment
power supply must comply with NEC Class 2, as described by the National Electrical Code
(r) (ANSI / NFPA 70).
EXPLOSION HAZARD
DO NOT CONNECT OR DISCONNECT EQUIPMENT WHEN A FLAMMABLE OR
COMBUSTIBLE ATMOSPHERE IS PRESENT.
EXPLOSION HAZARD
SUBSTITUTION OF COMPONENTS MAY IMPAIR SUITABILITY FOR CLASS I, DIVISION
2 OR ZONE 2.
When used in hazardous environments corresponding to Class I, Division 2 or Class I,
Zone 2, the device must be installed in a cabinet or a suitable enclosure.
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WARNING
WARNING
WARNING
WARNING
WARNING
WARNING
Operating Instructions, 01/2017, C79000-G8976-C427-02
CP 443-1 OPC UA