ERICO TSG Series Surge Reduction Filters (TSG-RSF) - Manual (Page 8)

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Identify the Distribution System
Figure 2. TN-C system: In this system, the neutral and protective earth conductor combine in a single
conductor throughout. All exposed conductive parts are connected to the PEN conductor.
4. IDENTIFY THE DISTRIBUTION
SYSTEM
A number of different power distribution
systems are employed in various countries
around the world. It is important to identify
the distribution system in use prior to installa-
tion of the SRF, and confirm that the SRF is
the model recommended by the manufactur-
er for that distribution system.
To identify the distribution system in use,
consult reputable and knowledgeable sources
such as:
• The local power supply authority
• Local electrical engineers
• Applicable regulatory bodies or standards
associations
Alternatively, confirm the type of distribution
system used by personal inspection. By visual-
ly tracing the neutral and earthing conductors
from the load equipment or sub-distribution
point back to the point of entry (and perhaps
to the supply transformer), the type of distri-
bution system should be identifiable with the
aid of the following diagrams (Figures 2-6).
These are prescribed in local regulations and
describe the relationship between the source,
exposed or conductive parts of the installa-
tion and earth. Amongst these, the TN-C,
TN-S, TN-C-S and TT systems are most
commonly encountered. Note that supplies
such as those used in industry and mining
may often use a different distribution system
to that of the local supply authority.
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