Delta C2000 Series User Manual page 673

TN system
TN: The neutral point of the low voltage transformer or generator is earthed, usually the star point in a
three-phase system. The body of the electrical device is connected to earth via this earth connection at
the transformer.
protective earth (PE): The conductor that connects the exposed metallic parts of the consumer.
neutral (N): The conductor that connects to the start point in a 3-phase system or that carries the return
current in a single phase system.
TN-S system
TN-S: PE and N are two separate conductors that are combined together only near the power source
(transformer or generator). It is the same as a three-phase 5-wire system.
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