How many main classes of hazardous locations are there?

The correct choice is based on the classification system established by the National Electrical Code (NEC), which recognizes three main classes of hazardous locations: Class I, Class II, and Class III.

Class I includes locations where flammable gases or vapors may be present, like areas around petroleum refineries or chemical plants. Class II pertains to locations where combustible dust may be present, such as grain elevators or coal handling facilities. Class III focuses on locations where easily ignitable fibers or flyings are present, typically found in textile manufacturing or woodworking plants. Each class is further divided into divisions that specify the level of risk and necessary precautions, highlighting the importance of understanding the hazards in different environments.

This structured classification is crucial for ensuring safety in environments where hazardous materials might pose risks, and it lays the groundwork for implementing appropriate protective measures and equipment.