User Manual

10 / 86
Siemens Desigo Room automation - Engineering, mounting and installation CM111043en_14
Smart Infrastructure Important information on safety 2020-10-30
3 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.
As a rule, comply with local regulations for electrical installations.
These take precedence over any notes in this document.
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 IEC 60364-4-41 "Low-voltage
electrical installations" depending on the grounding (^ AC24V) of the low voltage:
Ungrounded = Safety Extra-Low Voltage (SELV).
Grounded = Protection by Extra Low Voltage (PELV).
· Using an energy limited Class 2 transformer with max. 100 VA OR
Class 2 circuits with max. 100 VA each, using a non energy limiting transformer
with max. 400VA, combined with over-current protective devices (T 4 A fuses) for
each room automation station. Multiple fuses per transformer may be used to
provide multiple isolated secondary circuits, see 6.3.2.
Device-related safety is guaranteed, among others, by
– Low-voltage power supply AC 24 V
– Double insulation between mains voltage AC 230 V, AC 24 V circuits and
housing.
Comply with specific regulations for electrical wiring per the following sections.
Please comply
with these n
otes
Safety notes
General
Regulations
Safety
IEC (SELV, PELV)
(worldwide)
NEC
(North America)
Device safety