The masonry chamber for earthing should have brick masonry foundation.
The chamber should be constructed in such a manner that 40 mm diameter G.I. pipe earth electrode is at the center of the chamber.
The pipe electrode should be buried to the correct level such that its top is not less than 20 cm below ground level.
WIRING
Before fixing switch boxes in the wall, the space behind switch boxes should be filled with mortar properly.
The height of power plug/ light plug should be kept at least 125 cm above the floor and 30 cms above kitchen platform level.
The accessories like bell push, light, control switch, socket, etc. if provided in an area exposed to rain, they should be suitably protected by providing covers.
Wires should be drawn in the conduit before plastering.
Shock protector unit is to be provided to prevent any untoward happening in the building.
The in coming supply of power from the street should be through a cable of adequate size and laid in a pucca cable trench covered with RCC slab.
Installation of MCB-DB is preferable, since it will protect the wire from damage, due to over-loading.
All wires between which a difference of potential of 240 volts exists shall be made inaccessible to unauthorized persons or enclosed in a conduit.