Journeyman Electrician Practice Exam

Class II locations are considered hazardous due to the presence of what?

1. Flammable liquids

2. Combustible dust

3. Hazardous gases

4. Electrical currents

The correct answer is: Combustible dust

Class II locations are considered hazardous specifically due to the presence of combustible dust. These locations may have dust which can ignite and create a fire or explosion hazard when suspended in air. The classification is important for ensuring that appropriate safety measures and equipment are used to mitigate the risk associated with dust. In environments classified as Class II, the dust can accumulate on equipment and surfaces, and when dispersed, can ignite due to a source of ignition such as electrical equipment or static discharge. Recognizing this classification helps electricians and other professionals design and maintain safe industrial environments where such combustible materials are present. The other options refer to different categories of hazards: flammable liquids create a different classification (such as Class I), and hazardous gases represent yet another classification (generally Class I as well). While electrical currents can pose a risk in any environment, they do not define a hazardous location classification in the context of combustible dust.