Water-based extinguishers should not be used on electrical fires because water conducts electricity.

• A. Water conducts electricity and can pose a shock hazard
• B. They are safe if power is off
• C. They are the best choice for electrical fires
• D. They leave no residue

Answer: (A)

Water conducts electricity, so spraying a water-based extinguisher on an electrical fire can create a dangerous path for current to travel to you or other conductors. Even if the equipment is thought to be de-energized, there can be residual or unknown live parts, and water can still carry electricity through the extinguisher itself or across surfaces, posing a shock hazard and potentially energizing nearby metal. For electrical fires, the safer approach is to de-energize the circuit if it can be done safely and use a non-conductive extinguishing agent that's appropriate for electrical fires. The idea that power being off makes water safe is misleading, and these extinguishers are not the best choice for electrical fires. Residue is not the primary concern here; the main risk is creating a conductive path that endangers the operator.