4) The minimum cross-sectional area of a copper conductor used in a 'light and fan' sub circuit should be :

5) The minimum cross-sectional area of an aluminium conductor used in a 'light and fan' sub circuit should be :

6) The minimum cross-sectional area of a copper conductor used in a 'power' sub-circuit should be :

7) The minimum cross-sectional area of an aluminium conductor used in a 'power' sub circuit should be :

8) If mechanical and fire safety are important factors, the wiring should be :