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SarkariResultOutBMS · 2024

Previous Year Question

Twenty-five-foot tap rule generally referred to as the “25-ft tap rule” allows to omit overcurrent protection at the point of supply. Which of the following condition must be met under this rule?
  1. The smaller wire is not over 25 feet long and protected against physical damage.
  2. The smaller wire has an ampacity at least one-third that of the rating of the overcurrent device protecting the larger wire.
  3. The smaller wire ends in a single overcurrent device having an ampere rating not greater than the ampacity of the smaller wire.
  4. All of the above.

Correct answer: D

Explanation

The 25-ft tap rule permits omission of overcurrent protection at the tap point only when all prescribed conditions are met, including conductor ampacity, physical protection, length limitation and termination in a suitable overcurrent device/equipment. The complete condition set is represented by option D.

Formula

Tap length ≤25 ft and all code conditions must be satisfied

Step-by-step solution

Tap Conductor Conditions explanatory diagram

Correct Answer

D — All of the above.

Concept and Reasoning

The 25-ft tap rule permits omission of overcurrent protection at the tap point only when all prescribed conditions are met, including conductor ampacity, physical protection, length limitation and termination in a suitable overcurrent device/equipment. The complete condition set is represented by option D.

Calculation / Key Relation

Tap length ≤25 ft and all code conditions must be satisfied

Exam Takeaway

Tap rules are exceptions: every listed safety condition matters.

Common Mistake

Do not treat the 25-ft length by itself as sufficient compliance.

Common mistake

Do not treat the 25-ft length by itself as sufficient compliance.

Exam tip

Tap rules are exceptions: every listed safety condition matters.

Quick method

Tap rules are exceptions: every listed safety condition matters.