Plumbing Systems MCQ with answer and solution

Concept

Standard color coding of electrical wires in AC circuits to ensure safety and correct connections.

Step-by-step solution

1. Identify the components of a single-phase AC supply: Live, Neutral, and Earth. 2. Recall the traditional Indian standard color codes: Live = Red, Neutral = Black, Earth = Green. 3. Match the live wire to its corresponding color, which is Red.

Explanation

According to the Indian Standard (IS 694 / BIS guidelines) and traditional international wiring color codes, the live (phase) wire is conventionally coloured red (or brown under the newer IEC standard, but Red is standard for single-phase AC circuits in traditional Indian wiring).

Why the other options are wrong

A: Blue is conventionally used for neutral in newer standards (or sometimes live in multi-core cables, but traditionally Black/Blue are neutral). B: Green is used for the earth or protective conductor. D: Yellow is used for specific phase identification in three-phase systems.

Shortcut

Remember 'R' for Red and 'R' for Right/Live phase.

Common mistake

Confusing the live wire color with neutral (black) or earth (green).