Page 933 - Basic Electrical Engineering

Figure 13.13 Earthing terminal from a pipe or rod-type electrode

In the case of plate earthing, the plate electrode is made of galvanized iron

or steel. The size of the plate electrode should be 60 cm × 60 cm and should
be burried atleast 1.5 m below the surface of the soil.

All earth wires should be made of copper, galvanized iron, steel or
aluminum. Interconnections of earth continuity conductors should be such
that good electrical connections are permanently made. The neutral conductor

should not be used as earth wire.

Neutral and earth wire

Low-voltage supply at 230 V for single-phase supply and 415 V for three-
phase supply are obtained from the distribution transformer. The distribution
transformer is a step-down transformer whose primary windings are delta

connected and the secondary windings are star connected. The neutral point,
i.e., the star point of the secondary is earthed and the neutral wire is taken out

from the star point. Thus, the output from the distribution transformer is