Which extinguishing agent is NOT effective on electrical fires?

Water is not effective on electrical fires primarily because it is a conductor of electricity. When water is applied to an electrically charged source, it can create a pathway for the electrical current. This can lead to the risk of electric shock for anyone using water as an extinguishing agent. Additionally, using water can cause the electrical fire to spread if it comes into contact with energized equipment or systems, potentially resulting in explosive reactions or further damage.

In contrast, agents like foam, CO2, and dust are specifically designed to extinguish fires without conducting electricity. Foam forms a barrier that can effectively smother a fire, CO2 displaces oxygen and suffocates the fire, and dust acts as a non-conductive agent that can separate the fuel from the source of ignition. Therefore, these agents are safer and more effective choices for handling electrical fires.