what should be the size of the earth cable & for the neutral cable ?
Phase and neutral conductors ..... equal size
when phase conductor < 16mm² then earth conductor .... equal size
when phase conductor 16mm²...35mm² then earth conductor .... 16mm²
when phase conductor > 35mm² then earth conductor .... 0.5 x phase conductor
if separate neutral is not used then earth conductor must handle max. current in fail situations
( earth conductor minimum = phase conductor )
You must check above information from national requlations.
Neutral is a supply circuit conductor (that carries current in normal operation)
In a polyphase or three-wire (single-phase) AC system, the neutral conductor is intended
to have similar voltages to each of the other circuit conductors.
Ground or earth in a mains (AC power) electrical wiring system is a conductor that provides a low impedance path
to the earth to prevent hazardous voltages from appearing on equipment .
Under normal conditions, a grounding conductor does not carry current.