Assignment

1. The electrical installation of a shop with supply voltage of 380V, 3-phase is comprised with the following electrical loads:
Single phase load:

- 20 nos. of 36W fluorescent light fitting
- 4 nos. of air-conditioner unit with full load current of 10A each
- 3 nos. of 30A ring circuit using 13A socket outlets
- 3 nos. of refrigerator with full load current of 15A each

Three phase load:

- 2 nos. of cooking appliances with output power ratings of 8.2kW and 6.3kW respectively.
- 2 nos. of 9kW instantaneous type water heaters.

(a) Assuming that all of the above electrical loads are balanced across the 3-phase supply, determine the maximum current demand by applying suitable diversity factor as given in Table 7(1) of CoP.

(b) Draw a schematic wiring diagram to show all the final circuit arrangement according to the accepted practice of the Code of Practice for this shop.

Note: NO NEED to show the current rating of the protective devices and cable size of the final circuits in the schematic wiring diagram.