Which extinguishing agent is non-conductive and leaves no residue, making it suitable for energized electrical fires?

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

Answer: (A)

Carbon dioxide is the extinguishing agent that is non-conductive and leaves no residue. It extinguishes by displacing oxygen around the fire and blanketting the flames, which smothers the fire without leaving any particulate residue that could conduct electricity or contaminate electrical equipment. This makes it suitable for energized electrical fires where you need to avoid introducing conductive liquids or conductive residues.

In contrast, water conducts electricity and can cause short circuits or further damage to energized equipment; foam and dry chemical extinguishers leave residues that can be conductive or require cleanup and may foul sensitive components. However, always use CO2 with proper ventilation and awareness of asphyxiation risks in occupied spaces.