Which class of fire extinguisher is least effective against electrical fires?

Class A fire extinguishers are designed to combat fires involving ordinary combustible materials such as wood, cloth, paper, rubber, and many plastics. These extinguishers typically contain water or water-based agents that are effective against solid materials but can pose significant risks when used on electrical fires. The introduction of water can lead to electric shock or further complicate the situation by conducting electricity.

In contrast, Class C fire extinguishers are specifically formulated for electrical fires, utilizing non-conductive agents to ensure safety while effectively extinguishing the flames. Class B extinguishers are used for flammable liquids and gases, while Class D extinguishers are focused on combustible metals. Understanding the proper classes of extinguishers is critical for safety and effectiveness in emergency situations. Thus, Class A extinguishers are indeed the least effective and potentially hazardous option for addressing electrical fires.