Brochure/Catalogue

Network forms
Network forms to DIN VDE 0100 part 300 (DIN 57100 part 310)
Four-conductor systems:
Still valid according to VDE but unfavourable for information
technology systems from the point of view of EMC
(VDE 0100 pt 444 / pt 540 pt 2).
TN-C systems (“classic earthing”)
Neutral conductor and protective earth conductor functions
are combined throughout the network in a single conductor,
the PEN conductor.
TN-C-S systems (“modern earthing”)
Neutral conductor, PEN conductor and equipotential bonding
system are connected once at the main distribution board
or after the incoming supply to the building. Therefore, a
TN-C system becomes a TN-S system (TN-C-S system) from
this point onwards.
The letters in this table describe the earthing conditions:
1st letter
Earthing at current source
2nd letter
Earthing of exposed conductive
parts of electrical installation
3rd letter
Routing of N and PE conductor
(only applies to TN systems)
T-
Direct earthing of current source
(of transformer)
T-
Exposed conductive parts of electrical
installation are earthed directly
C-
“Combined” N conductor and
PE conductor are routed together as
PEN conductor from current source
into electrical installation
I-
Insulated structure of current source
N-
Exposed conductive parts of
electrical installation are connected
to earth of current source
S-
“Separate” N conductor and
PE conductor are routed separately from
current source to exposed conductive
parts of electrical installation
W
The basics of lightning and surge protection
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