Siemens SIMATIC S7-1500 System Manual page 170

Wiring
7.1 Rules and regulations for operation
Line voltage
The points to note for line voltage are set out below:
• For fixed plants or systems without multipole circuit breaker, a mains disconnection device
(multipole) must be available in the building installation.
• For the load current supply, the configured rated voltage range must correspond to the
local line voltage.
• For all power circuits of the S7‑1500R/H redundant system, the fluctuation/deviation of
the line voltage from the rated value must be within the permitted tolerance.
You can find more information in the section Specifications for insulation tests, protection
class, degree of protection, and rated voltage (Page 364).
24 V DC supply
The points to note for a 24 V DC supply are set out below:
• Power supply units for the 24 V DC supply (SELV/PELV) must supply safety extra low
voltage in accordance with IEC 61131-2 or IEC 61010-2-201.
• To protect the S7‑1500R/H redundant system from lightning and overvoltages, use
overvoltage arresters.
Suitable components for the lightning and overvoltage protection are specified in the
Defining interference-free controllers
(https://support.industry.siemens.com/cs/ww/en/view/59193566) function manual.
Requirements for power supplies in the event of voltage interruption
NOTE
To ensure adherence to IEC 61131-2, only use power packs/power supply units (e.g.
230/400 V AC → 24 V DC) with a mains buffering time of at least 10 ms. Observe the relevant
requirements in your application (e.g. product standard for "burners" 30 ms according to EN
298 or 20 ms according to NAMUR recommendation NE 21) with respect to possible voltage
interruptions. The latest up-to-date information on PS components is available on the
Internet (https://mall.industry.siemens.com).
Of course, these requirements also apply to power packs/power supply units not constructed
using S7-1500 or ET 200SP/S7-300-/S7-400 technology.
Protection against electrical shock
The mounting rails of the S7‑1500R/H redundant system must be connected conductively to
the protective conductor to protect against electric shock.
You may only use conductors in the colors yellow-green for connections to protective
conductor connections.
170
S7-1500R/H redundant system
System Manual, 11/2022, A5E41814787-AD