What is the primary fire extinguishing agent for Class Charlie fires?

• A. CO2
• B. Water
• C. Fog attack
• D. Dry chemical

Answer: (C)

Class Charlie fires involve live electrical equipment, so the extinguishing medium must be non-conductive and safe to apply around energized gear. Carbon dioxide fits this need well: it rapidly displaces the surrounding air and cools the flame without leaving an electrically conductive residue, which helps prevent shock hazards and damage to equipment. Dry chemical is also effective because it interrupts the chemical reactions occurring in the flame and coats energized surfaces, reducing the chance of reignition.

Water-based options are not preferred for electrical fires because water conducts electricity, creating shock hazards and potential further damage to equipment. A fog attack refers to the method of applying water as a fine spray, not an extinguishing agent itself, so it isn’t considered a primary solution for live electrical fires.

So, for Class Charlie fires, non-conductive agents like carbon dioxide (and also dry chemical) are the primary choices, with water-based methods avoided around live electrical equipment.