Generally, a single-phase power is commonly found in domestichouseholds, whereas a three-phase power is preferable for largerdemands. For safety purpose, over-current protection components arecompulsory in the electrical distribution systems.
i. Explain two advantages of a three-phase system compared to asingle-phase system in the distribution system.
ii. Briefly describe the characteristic and the function of twotypes over-current protection device installed in the distributionboard (DB) residential building.
iii. Miniature circuit breakers (MCB) with different current ratingcan be used to protect the individual sub-circuit. State thecurrent rating of the MCB that typically used for:
• lighting,
• socket outlet (radial type),
• socket outlet (ring type) and
• air-conditioner circuits.
