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GENERATOR: August 2008

Monday, August 4, 2008

Earthing System

Panel boards are selling several Countries then earthing systems and main Bus bar arrangement are changed each country.

Type of System Earthing

01. TN system:

TN power system have one point directly earthed, the exposed conductive parts of the installation being connected to that point by protective conductors. Three types of TN systems are recognized, according to the arrangement of neutral and protective conductors,

(a) TN-S System – A system having separate neutral and protective conductors throughout

(b) TN-C-S System – A system in which neutral and protective function are combined in a single conductor in a part of system.

(c) TN-C system - A system in which neutral and protective functions are combined in a single conductor throughout.

02. TT System -

The TT power system has one point directly earthed, the exposed conductive parts of the installation being connected to earth electrodes electrically independent of the earth electrodes of the power system,

03. IT System -

The IT power system has no direct connection between live parts and earth, the exposed conductive parts of the electrical installation being earthed