990–91278–001

Decoding the Earthing Types

First letter T Connected directly to main earth at a certain point in the power system, normally at the supplying transformer (T = Terra (Earth)).
I The power system is insulated from earth or connected to earth through a sufficient high impedance (I = Isolated).
Second letter T The exposed conductive parts are connected directly to earth e.g. the UPS chassis disregarding whether the power system is earthed or not.
N The exposed conductive parts e.g. the UPS chassis are connected directly to earth at the main earthing point (N = Neutral).
Additional letters S The Protective Conductor (PE) and Neutral Conductor (N) are two different and separate conductors (S = Split).
C The Protective Conductor (PE) and Neutral Conductor (N) are one common conductor (PEN) (C = Common).
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