Table of Contents
Advertisement
Chapter 12 Helpful information
TT system
The term TN-TT comes from the French Terre-Terre and is shown in
In a TT earthing system, the protective earth connection for the user is provided by a local
earth electrode, (sometimes referred to as the Terra-Firma connection) and there is another
independently installed at the generator or transformer. The connection of the PE of the
building and the transformer is done without any wires via the ground itself. There is no
connection between N and PE in the Power supply system of the customer. The utility power is
supplied at the transformer to the customer with 4-poles (L1, L2, L3, N). In order for a TT
earthing system to work safely without any problems in an IT environment it is imperative that
flawless earth connectors with low impedance are used. The power supply unit in the building
itself must be implemented as a TN-S earthing system.
Due to the way the TT system works RCDs (GFCIs, Ground Fault Circuit Interrupter device)
must be installed.
210
Figure 6 2
6U Rack or Tower UPS RT8kVA and RT11kVA IUOMG
.
Advertisement
Table of Contents
