Ingeteam INGECON SUN STORAGE 1Play Technical Manual page 10

INGECON SUN STORAGE 1Play
TT Network
In a TT system, there is a connection to the earth in the grid distributor´s transformer, usually the star point of
a three-phase system. However, it is provided a connection to the local earth electrode. As the fault loop
impedance is usually high, those systems should always have a Residual Current Detector.
Figure 7: TT system
TN Network
In a TN system, as in TT systems, there is a connection in the grid generator´s transformer to Earth. However,
the bodies of the electrical devices are connected to a so called Protective Earth wire. This wire is related to
the Neutral wire, but depending on the connection point, three variants are distinguished:
TN-C Network
A combined conductor fulfills the functions of both PE and Neutral wires. This combined wire is called PEN.
TN-S Network
PE and N are separate wires from the distribution point.
TN-C-S Network
PE and N come combined from the distribution point, but they are separated (usually at the building
distribution point) before getting to the consumer.
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Technical Guide 10/11/2017