What is used for a class Charlie fire?

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

Answer: (D)

Class Charlie fires involve energized electrical equipment, so the extinguishing agent must be non-conductive and safe for live electrical gear. Carbon dioxide fits this need because it blankets the fire and displaces the surrounding oxygen, producing a quick knockdown without leaving a conductive residue that could cause current paths or equipment damage. Water is dangerous on live electrical systems because it conducts electricity and can create shock risk; foam behaves similarly and can spread or leave residues that harm equipment. Dry chemical can extinguish electrical fires, but its powder residue can foul components and complicate repairs, so CO2 is the preferred choice for energized electrical fires.