Energized electrical equipment and the surrounding area are best protected with extinguishers that have a _______ rating.

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

Answer: (C)

Fires involving energized electrical equipment require extinguishing agents that won’t conduct electricity. Extinguishers rated for electrical fires—Class C—are designed for this situation. Their agents are non-conductive, so discharging them on live equipment reduces the risk of electric shock to the person using the extinguisher and avoids creating a new path for electricity. Water-based or other non‑rated extinguishers can create a shock hazard or fail to interrupt the current, making the situation more dangerous. In practice, if it’s safe to do so, power should be shut off first, but when the equipment is still energized, Class C extinguishers provide the best protection for the equipment and nearby area.