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C2. A small restaurant connecting with a 380V, three-phase supply will be installed with the following electrical loads: 220V Single-phase loads: - 40 nos. of 8W LED downlight - 10 nos. of 28W T5 fluorescent light fitting with 2W electronic ballast - 4 no. of 30A ring final circuit using 13A socket outlets (code 6E) - 5 nos. of Air Conditioning units. The full load current of each unit is 10A 1 no. of 4000W espresso coffee machine. 380V Three-phase loads: - 2 nos. of 18kW water heater with unity power factor - 2 nos. of 10kW electric cooker-0 with 0.98 power factor 1 nos. of 18kW electric oven with unity power factor 1 nos. of 18kW steam cooker with unity power factor With the use of the diversity factor as shown in Appendix 1, determine the maximum demand of the restaurant. (6 marks)
Appendix Type of Premises Purpose of Individual Household Conductors or Installations, Small shops, Stores Small Hotels Switchgear to which Individual Dwellings Offices and Business Boarding Houses Diversity Applies of a Block Premises Guest Houses, etc. 1. Lighting 66% of total current 90% of total current 75% of total current demand demand demand 2. Heating and 100% of total current 100% f.l. of largest 100% f.l. of largest Power Also see demand up to 10 appliance-75% appliance-80% 71. 3 to 10 below) amperes+50% of of remaining of 2nd largest any current demand appliances appliance-60% in excess of 10 of remaining amperes appliances 3. Cooking 10 amperes+30%. 100% fl. of largest 100% .I. of largest Appliances of connected cooking, appliance+B0% I appliance-80% appliances in excess of of 2nd largest of 2nd largest 10 amperes+5 amperes appliance+60% .. if socket outlet of remaining appliance 60%. of remaining incorporated in unit appliances appliances 4. Motors (other 100% fl. of largest 100% .I. of largest than lift motors motor 80% fl. of motor+50% fl. of see 8) 2nd largest motor remaining motors 60% t. of remaining motors 5. Water Heaters 100% fl. of largest 100% f.I. of largest 100% fl. of largest instantaneous appliance+100% fi appliance+100% f. appliance+100% f. type) of 2nd largest of 2nd largest of 2nd largest appliance+25% 0.1 appliance+25% fl appliance+25% f.I. of remaining of remaining of remaining appliances appliances appliances 6. Water Heaters (thermostatically No diversity allowable controlled 7. Thermal Storage Note: It is important to ensure that the distribution board is of sufficient rating to take the total load connected to it without Space Heating Installations the application of any diversity 8. Lift motors Note: Subject to requirements specified by the lift engineer registered under Cap. 618, Lifts & Escalators Ordinance 9. Water Pumps 100% f.I. of the largest pump motor and 25% of the remaining motors 10. Air conditioners 100% fl. of the 100% of current 100% of current largest air-conditioner demand of largest demand of largest in the premises and point of utilisation+ point of utilisation+ 40% fl. of the 75% of current 75% of current remaining air demand of every other demand of every other conditioners) point of utilisation point of utilisation 11. Arrangements of 100% of current 100% of current demand of largest circuit Final Circuits in demand of largest 40% of current demand of every other circuit accordance with circuit+30% of code 6D current demand of every other circuit 12. Arrangements of 100% of current 100% of current demand of largest circuit Final Circuits in demand of largest 50% of current demand of every other circuit accordance with circuit-40% of code 6E current demand of every other circuit 13. Fixed Equipment 100% of current 100% of current 100% of current of the same type demand of largest demand of largest demand of largest e.g. Refrigerators point of utilisation+ point of utilisation point of utilisation and freezers 40% of current 75% of current 75% of current other than those demand of every other demand of every other demand of every point listed above point of utilisation point of utilisation in main rooms (dining rooms, etc.) + 40% of every other point of utilisation