Technical Documentation: Fire Detectors used in hazardous areas
P-DET/EX/RCE/PM5/GKa/110995 11 Autronica Fire and Security AS
1.5 Installation fire alarm equipment in hazardous area.
This description can not, of course, include every possible installation of
electrical equipment in hazardous area.
Therefore, the most common rules are mentioned below:
In power distribution systems with earthed zero terminal, the earth wire and the
zero terminal shall be kept insulated inside hazardous area. A common earth-
and zero wire (PEN-wire) is not allowed.
Comment:
Common earth- and zero-wire (PEN-wire) may be utilized for that part of the
distribution network outside the hazardous area.
Distribution systems with insulated zero wire must have an earth fault operating
switch breaking the circuit at a current of 500 mA, or have facility which by
audible or visible signal gives warning of earth fault in the system.
When an earth fault is given, the fault must be repaired immediately.
Earth wire must physically be situated in the same tube as the feeding wires.
(Separate earth wires are not accepted.)
Comment:
The claims do not exclude use of separate earth wire as equipotential connec-
tion in addition to common safety earth wire. Such equipotential connection
ought to be used for special exposed system parts, e.g. construction elements of
electrically conducting material, pipes etc. in order to avoid potential difference
and consequently danger of electrostatic charges.
In addition to the comments above, it must be mentioned that the term
equipotential connection is differently abbreviated in different documents, such
that PA-, PE-, a.o.
In this document the term PE- is preferred.
1.6 Installation of Autronica fire alarm systems in
hazardous areas.
Several approval authorities have more or less equal norms to be the recom-
mending and normgiving authorities respectively. But we must recommend you
to obtain the laws and regulations concerning your country, because slightly
different rules exists in different countries.
Installation fire
alarm equipment
in hazardous area
Installation of
Autronica
fire alarm in
hazardous area
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