gefran ADV200 Series

ADV200 • Quick start up guide 25
er des problèmes de sécurité. Filtres spécials pour Réseaux IT sont disponibles
sur demande.
Power supply networks
Based on the grounding method, the IEC 60634-1 describes three main types of
grounding for power supply networks: TN, TT and IT systems.
In particular, the IT system has all the active parts insulated from earth or a point
connected to ground through an impedance. The earths of the system are con-
nected separately or collectively to the system ground.
The following gures show these different systems.
TN-S supply lines TN-C supply lines
L1
L2
L3
N
PE
L1
L2
L3
PEN
TT supply lines IT supply lines
L1
L2
L3
N
PE
L1
L2
L3
PE