Which agent is used for class Charlie fires?

• A. Water
• B. Foam
• C. Dry Chemical
• D. CO2

Answer: (D)

Class Charlie fires involve energized electrical equipment, so the extinguishing method should avoid conducting electricity and minimize damage to sensitive gear. Carbon dioxide fits this need by displacing the surrounding oxygen and blanket-fogging the area, which rapidly suppresses the flame without leaving conductive residue. It’s particularly effective in enclosed electrical rooms or panels where the fire is contained, and because it is non-conductive and clean, it won’t create new electrical problems as some other agents might.

Water and foam are risky for electrical fires because they conduct electricity and can spread current through the firefighting medium, increasing shock hazard and potentially shorting other components. Dry chemical can knock down the fire, but it leaves a powdery residue that can foul contacts and systems, complicating restart and maintenance. That makes carbon dioxide the clearer choice for safely and effectively handling energized electrical fires.