Important Information On Safety; System-Specific Regulations - Siemens Desigo TRA Mounting And Installation Manual

Please comply with
these notes
Safety notes
. General
Regulations
Safety
SELV, PELV
. Device safety
. Grounding of ⊥
(System neutral)
Recommendation on
Grounding ⊥
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Siemens
Building Technologies
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Important information on safety

This section deals with general and system-specific regulations. It includes
important information for your safety and the safety of the entire plant.
Sections flagged with the warning symbol to the left contain safety-related
requirements and restrictions that must be adhered to at all times to prevent
physical injury and equipment damage.
Please comply with the following general regulations during engineering and
execution:
• Electrical and mains power ordinances for the given country.
• Other applicable, national regulations.
• Building installation regulations for the given country.
• Regulations of the facility supplying electricity.
• Diagrams, cable lists, dispositions, specifications and orders by the customer or
authorized engineering office.
• Third-party regulations, e.g. by the general contractor or building owner.
3.1

System-specific regulations

The electrical safety for building automation and control systems by Siemens
Building Technologies is essentially based on safely separating low voltage from
mains voltage.
Application as per SELV or PELV pursuant to HD 384 "Electrical installation of
buildings" depending on the grounding (⊥ AC24V) of the low voltage:
Ungrounded = Safety Extra-Low Voltage (SELV).
Grounded = Protection by Extra Low Voltage (PELV).
Device-related safety is guaranteed, among others, by
– Low-voltage power supply AC 24 V per SELV or PELV
– Double insulation between mains voltage AC 230 V and SELV/PELV circuits and
housing.
Comply with specific regulations for electrical wiring per the following sections.
Observe the following points when grounding ⊥ AC 24 V (system neutral):
• Operating voltage of AC 24 V is permitted in principle for both grounded as well
as non-grounded system neutral. Local regulations and customers apply
accordingly.
• Grounding may be required or not allowed for functional reasons.
• AC 24 V systems are generally grounds unless otherwise not recommended
by the manufacturer.
• In order to avoid ground loops, connect systems with PELV to the ground at one
location only (especially for transformers), if no other indication exists.
Mounting and installation
Important information on safety
CM111043en_03
2013-02-23