Which of the following fire extinguishing agents should never be used on electrical fires?

Water should never be used on electrical fires because it is an excellent conductor of electricity. Using water can create a significant risk of electrocution to the person attempting to extinguish the fire as it can travel along the surface of the water and conduct electricity. In addition, applying water to live electrical equipment can further damage the equipment and make the situation more hazardous.

In contrast, dry chemical extinguishers and CO2 extinguishers are designed to safely smother and interrupt the chemical reaction occurring in an electrical fire. Foam extinguishers, while effective for some types of fires, are generally not recommended for electrical fires either, but they are not as hazardous as water. It's crucial to always utilize the appropriate fire extinguishing agents that are specifically rated for electrical fires to ensure safety and effectiveness.