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Most suitable way of providing electrical supply to a multi story building is by means of
Ring main
Overhead line
Insulated cable
All of above
Ring main
The Ring Main system is the most suitable distribution method for multi-story buildings because it provides high reliability and voltage stability. In this configuration, the supply conductor forms a closed loop, ensuring that if a fault occurs in one section, the load can still be fed from the other side of the ring.
The Ring Main system is the most suitable distribution method for multi-story buildings because it provides high reliability and voltage stability. In this configuration, the supply conductor forms a closed loop, ensuring that if a fault occurs in one section, the load can still be fed from the other side of the ring.
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In a Ring Main system, the feeder enters the building and circulates through the various floors or distribution boards to return to the starting point. This creates a parallel supply path for each load center, significantly reducing the voltage drop and ensuring that power is available even during a single-point cable failure.
Redundancy: Provides two paths for current to flow to each load point.
Voltage Regulation: Minimizes voltage drop across the building compared to radial systems.
Maintenance: Allows isolation of sections for maintenance without disconnecting the entire building.
High reliability and continuous supply
Uniform voltage distribution
Smaller conductor cross-section compared to radial feeders
Complex circuit breaker and protection coordination
Higher initial installation cost
Requires more cable length
Multi-story residential apartments
Industrial complexes
High-density commercial buildings
| Feature | Ring Main | Radial |
|---|---|---|
Reliability | High (Dual path) | Low (Single path) |
Radial distribution is cheaper but unsuitable for large buildings due to high voltage drops at the end of the line.
Overhead lines (Option B) are generally prohibited inside high-rise buildings for safety and aesthetic reasons.
Insulated cables (Option C) are components, not a system topology.
A is correct тАФ The ring main system is preferred due to its superior reliability, lower voltage drops, and flexibility in supply continuity during faults.
Always remember that in distribution systems, 'Ring Main' relates to reliability and 'Radial' relates to simplicity/cost; choose based on the criticality of the load.