Siemens Simatic S7-1500R System Manual page 310

S7-1500R/H redundant system
System Manual, 10/2018, A5E41814787-AA
Symbol Meaning
For Zone 2 potentially explosive atmospheres, be aware that the device may only
be used when it is installed in an enclosure with a degree of protection ≥ IP54.
For Zone 22 potentially explosive atmospheres, be aware that the device may
only be used when it is installed in an enclosure with a degree of protection ≥
IP6x.
C.2 Safety-related symbols for devices with Ex protection
Safety symbols
309