Question

Fire extinguishers used to extinguish electrical fires are labelled as Class ________.

• A. C
• B. D
• C. E
• D. K

Hint:

Never use water (Class A) on an electrical fire. Water is highly conductive and can cause severe electric shocks to the operator, or cause the fire to spread rapidly. Use carbon dioxide ($\text{CO}_2$) or dry chemical powder (DCP) extinguishers instead.

Answer 1

The Correct Option is A

Step 1: Understanding Fire Classifications:
Fires are classified into different categories based on the fuel source to ensure the correct, safe extinguishing agent is used.

Step 2: Analyzing the Classifications:
Under the widely used US NFPA 10 standard, which forms the basis for many introductory vocational and engineering textbooks:

• Class A: Fires involving ordinary combustibles (wood, paper, trash).
• Class B: Fires involving flammable liquids (gasoline, oil, paint).
• Class C: Fires involving energized electrical equipment (motors, transformers, appliances).
• Class D: Fires involving combustible metals (magnesium, titanium, sodium).
• Class K: Fires involving cooking media (vegetable oils, animal fats in deep fryers).

Step 3: Evaluating the Options:
While some European and modern Indian standards (IS 15683) categorize electrical hazards under a distinct Class E or use a dedicated electrical hazard symbol alongside standard classes, the traditional classification taught in CBSE vocational curricula identifies electrical fires as Class C, corresponding to option (A).