What type of extinguisher would be inappropriate for use on electrical fires?

Using a water extinguisher on electrical fires is inappropriate because water is a conductor of electricity. If water comes into contact with live electrical equipment or wiring, it can create a significant risk of electric shock to the person attempting to extinguish the fire. Furthermore, applying water could cause the fire to spread by allowing electrical currents to travel through the water.

In contrast, extinguishers such as CO2 and dry chemical are effective on electrical fires. CO2 extinguishers are particularly advantageous because they displace oxygen and do not conduct electricity, providing a safe means of extinguishing fires caused by electrical equipment. Dry chemical extinguishers, like ABC models, can also effectively interrupt the combustion process without posing a risk of electrical conduction. Foam extinguishers, while primarily used for flammable liquid fires, are generally not recommended for electrical fires either due to potential conductivity, but they have some applicability in specific scenarios involving combination risks.

Thus, the safest and most suitable approach to extinguishing electrical fires excludes the use of water extinguishers.