What is a key precaution when using a water glycol extinguisher?

The key precaution when using a water glycol extinguisher is to never use it on electrical fires. This is crucial because water-based extinguishing agents, including those containing glycol, conduct electricity. If deployed on an electrical fire, the extinguisher can create the risk of electric shock to the user, and instead of extinguishing the fire, it may inadvertently spread it or cause further hazards.

Water glycol extinguishers are specifically designed for class A fires involving solid combustibles like wood and paper, but are not suitable for fires that involve energized electrical equipment. This safety guideline helps prevent injury and ensures proper firefighting procedures.