Journeyman Electrician Practice Exam

Class III locations are hazardous due to the presence of which materials?

1. Corrosive liquids

2. Easily ignitable fibers

3. High voltage components

4. Non-combustible dust

The correct answer is: Easily ignitable fibers

Class III locations are classified as hazardous due to the presence of easily ignitable fibers or flyings. These environments may contain materials that can become airborne and ignite easily when coming into contact with a spark or heat source. In these locations, the risk of fire or explosion is heightened due to the nature of the combustible fibers, which can pose significant safety risks in work or operational environments. While corrosive liquids can be hazardous and high voltage components may present electrical risks, they do not specifically define a Class III location. Non-combustible dust, although it may be present in some industrial settings, does not contribute to the ignition hazard that characterizes Class III locations. Thus, easily ignitable fibers are the key concern in such classifications.