Which of the following is NOT a common cause of electrical fires?

Flammable liquids are indeed not a common cause of electrical fires, as they are typically associated with fire hazards in general rather than specifically with electrical systems. Electrical fires generally originate from issues linked to the electrical wiring, appliances, and circuits. Poor wiring can lead to short circuits or overheating, overloaded circuits can cause excessive heat buildup, and faulty appliances may malfunction, leading to sparks or electrical failures. Each of these conditions poses significant risks directly linked to electrical failures, thereby making them more relevant causes of electrical fires compared to flammable liquids, which relate more to combustible materials rather than electrical issues.