Siemens 6FC5403-0AA21-0AA1, Equipment Manual

Page: 83 / 96

7.4.1 Power supply
Requirements for DC power supplies
WARNING
Electric shock due to connection of an unsuitable power supply
If equipment is connected to an unsuitable power supply and/or insufficiently grounded or rear
cover, exposed components may carry a hazardous voltage that might result in serious injury
or death.
• Only use power supplies that provide SELV (Safety Extra Low Voltage) or PELV (Protective
Extra Low Voltage) output voltages acc. to UL 61010 for all connections and terminals of the
electronics modules.
WARNING
Inadequately fused supply cables can be life-threatening
If power supply cables are inadequately protected, then lightning strikes can result in a surge
voltage. This can result in death, serious injury and material damage.
In the case of supply lines > 10 m, protectors must be installed at the device input in order to
protect against lightning (surge).
The DC power supply must be connected to the ground/shield of the NC for EMC and/or
functional reasons. For EMC reasons, this connection should only be made at one point. As a
rule, the connection is provided as standard in the S7-300 I/Os. In exceptional circumstances
when this is not the case, the ground connection should be made on the grounding rail of the
NC cabinet (also refer to /EMC/EMC Installation Guide.)
WARNING
Electric shock in the event of an individual error if the rear cover is missing
If the rear cover is missing when mounting the device in an environment with a hazardous
voltage, a conductor with a hazardous voltage can come loose in the event of a normative
permissible individual error and touch parts of the printed-circuit board and cause electric
shocks. Due to its design, the printed-circuit board cannot trigger the overcurrent protection of
the circuit with hazardous voltage.
For this reason, protect areas of the printed-circuit board that are not adequately enclosed by
grounded sheet metal parts, or with a secure cover when installed in an environment with
hazardous voltages. If this cover is made of conductive material, it must be safely grounded.
See "Electric shock in the event of an individual error when grounding is insufficient".
To avoid electric shocks, mount a rear cover on the device when installing it in an environment
with a hazardous voltage.
Technical specifications
7.4 Supplementary electrical conditions
Handheld Terminal HT 10
Equipment Manual, 09/2020, A5E47430965B AA
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