Energized electrical equipment and the surrounding area are best protected with extinguishers that have which rating?

• A. Class A
• B. Class B
• C. Class C
• D. Class D

Answer: (C)

Fires involving energized electrical equipment require extinguishers rated for electrical fires. The Class C rating identifies extinguishers that are nonconductive and appropriate for use on live electrical equipment without energizing the circuit or posing a shock hazard to the operator. This is critical because using water-based or non–electrical-rated extinguishing agents on energized circuits can conduct electricity and put you at risk while potentially spreading the fire. If safe to do so, de-energize the equipment before fighting the fire, but if that isn’t possible, a Class C–rated extinguisher provides the best protection around live electrical gear. Other ratings correspond to different fuel types (ordinary combustibles, flammable liquids, metals) and do not address electrical hazards.