With reference to Busbar Trunking Systems (BBT) in high-rise buildings:1.They are used as an alternative to heavy cabling for vertical power distribution.2.BBT systems offer better flexibility for adding "tap-off" points compared to cables.3.They have higher voltage drops over long distances compared to copper cables of the same rating.Which of the statements given above is/are correct?

Correct Answer: C - 1 and 2 only

Quick Concept Explanation

Busbar trunking distributes high current through enclosed rigid bus conductors and is widely used for vertical risers in high-rise buildings. Plug-in/tap-off units make load additions and reconfiguration easier than replacing large cable runs. Key relation: ΔV depends on I(R cosφ + X sinφ) and run length.

Exam focus: Tap-off flexibility is a key BBT advantage. Common trap: Do not assume busbar trunking always has higher voltage drop.

Statement-wise Verification

• Statement 1 - Correct.
  They are used as an alternative to heavy cabling for vertical power distribution.
  Busbar trunking distributes high current through enclosed rigid bus conductors and is widely used for vertical risers in high-rise buildings.
• Statement 2 - Correct.
  BBT systems offer better flexibility for adding "tap-off" points compared to cables.
  Tap-off flexibility is a key BBT advantage.
• Statement 3 - Incorrect.
  They have higher voltage drops over long distances compared to copper cables of the same rating.
  Voltage drop depends on impedance and design; busbar trunking is not inherently worse than an equivalent cable of the same duty

Core Concept

Busbar trunking distributes high current through enclosed rigid bus conductors and is widely used for vertical risers in high-rise buildings. Plug-in/tap-off units make load additions and reconfiguration easier than replacing large cable runs. Voltage drop depends on conductor impedance and rating; it is not inherently higher than an equivalent cable system.

Formula / Key Relationship

ΔV depends on I(R cosφ + X sinφ) and run length.

Why the Other Options Are Wrong

Option A is incorrect because it includes incorrect statement(s) 3 and omits correct statement(s) 1, 2. Option B is incorrect because it includes incorrect statement(s) 3 and omits correct statement(s) 1. Option D is incorrect because it includes incorrect statement(s) 3.

Exam Shortcut / Approach

Tap-off flexibility is a key BBT advantage.

Common Mistake

Do not assume busbar trunking always has higher voltage drop.

Quick Revision

Vertical Distribution and Tap-Offs is linked with Busbar Trunking, Power Distribution and Electrical Building Services. Tap-off flexibility is a key BBT advantage.