Which portable extinguisher is suitable for use on electrical fires?

A dry chemical extinguisher is suitable for use on electrical fires because it effectively suppresses flames without conducting electricity. These extinguishers discharge a fine powder, typically composed of sodium bicarbonate or potassium bicarbonate, which disrupts the chemical reaction of the fire, smothering it. The non-conductive nature of the dry chemical agents ensures safety when dealing with electrical hazards.

In contrast, a foam extinguisher is primarily designed for flammable liquids and may not be appropriate or safe for use on electrical fires, as it can conduct electricity and create additional risks. Similarly, a water extinguisher is particularly dangerous in extinguishing electrical fires because water is a conductor of electricity and can lead to severe hazards, including electric shock. Therefore, the dry chemical extinguisher is the correct and safe choice for addressing electrical fires in a fire emergency.