TT system (earthed neutral)

One point at the supply source is connected directly to earth. All exposed- and extraneous-conductive-parts are connected to a separate earth electrode at the installation. This electrode may or may not be electrically independent of the source electrode.

What is TT and TN earthing?

Using these, the three earthing families defined in IEC 60364 are TN, where the electrical supply is earthed and the customer loads are earthed via neutral, TT, where the electrical supply and customer loads are separately earthed, and IT, where only the customer loads are earthed.

What is TT wiring?

The TT method refers to a protective system that directly grounds the metal housing of an electrical device, which is called a protective earthing system, also called a TT system.