SOLUTION

The subcircuit of the electrical installation feeding supply to various light points, that is lamps, tubes, etc. and to fan points, that is ceiling and table fans, etc. is termed as light and fan sub-circuit, respectively.

1. While planning this circuit for a residential building, the following points must be given proper consideration.
2. The number of light and fan points connected in one sub-circuit should not exceed ten.
3. The total load connected in a sub-circuit should not be more than 800 W.
4. Control of light and fan points in any sub-circuit should be carried out by 5 A switches fitted on a switchboard
5. Socket outlets provided in these sub-circuits should be of a 5 A rating.
6. Only a single-phase supply should be fed to these sub-circuits.