Atlas Copco GA 160 VSD Instruction Book page 58

Atlas Copco strongly recommends that customers do not connect the neutral conductor from the power supply
to the compressor unit. The exposed conductive parts of the installation must be earthed locally. (EN 60204-1
par.: 7.2.3)
Power distribution systems (TN, TT, IT)
According to IEC 60950, there are three main types of power distribution systems: TN, TT and IT. The
electrical installation instructions depend on the type of network of the customer's power supply.
Network type TN (Terra Neutral) :
The TN power distribution system provides a direct earth to the exposed conductive parts of the installation.
The connection is made through the PEN-conductor. Within the TN power distribution system, there are three
sub-types: TN-S, TN-C and TN-C-S, identified according to neutral and protective earth conductors. Nearly
85 % to 90 % of industrial networks are TN type.
Network type TN-S (Terra Neutral-Separate) :
The TN-S power distribution system provides separate neutral and direct earth conductors.
A
B
Network type TN-C (Terra Neutral-Combined) :
In the TN-C power distribution system, the neutral and the protective earth functions are combined in a single
conductor.
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Power system earth
Exposed conductive parts
Instruction book
APF192090