Page 132 - Electrician - TT (Volume 1)

ELECTRICIAN - CITS

Fig 7 Fig 8

Principle of laying out of domestic wiring

Objectives: At the end of this lesson you shall be able to:
• explain the layout, installation plan, circuit -diagram, wiring diagram and state their uses
• state the B.I.S. regulation pertaining to wiring installation.

In electrical wiring work, the electrician is supplied with a layout of wiring installation and an installation plan
initially.
On the basis of the layout and installation plan, the electrician should draw the circuit and wiring diagrams before
the commencement of work for systematic execution of the work.
The terms used in wiring installation drawings are explained here.
Layout diagram: Some customers give their requirements in writing. But a few can give them in the form of a
layout diagram to the electrician.
The layout diagram (Fig 1) is a simplified version of the wiring diagram. Its purpose is to inform the reader quickly
and exactly, what the circuit is designed for without giving any information on the circuit itself.

This type of layout diagram is used for preparing architectural diagrams, plans, etc. of a building.
In a layout diagram, it is necessary to indicate with symbols details like whether the wiring is on the surface or
concealed, and the run `up’ or `down’, the number of wires in run, dimensions, and accessories with appropriate
I.S. symbols.
Installation plan (Fig 2): This plan shows the physical position of accessories in an installation, and also gives
the final appearance of the installation.

Fig 1 Fig 2

Circuit diagram (Fig 3): This shows the schematic connections of the circuit for a specific task in the simplest
form, incorporating the graphical symbols.

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CITS : Power - Electrician & Wireman - Lesson 20-25 CITS : Power - Electrician & Wireman - Lesson 20-25