The NEC identifies environments that contain flammable vapors and gases as which class of hazardous location?

The NEC identifies environments that contain flammable vapors and gases as which class of hazardous location?

• A. Class I
• B. Class II
• C. Class III
• D. Class IV

Answer: (A)

Environments with flammable gases or vapors are classified as Class I hazardous locations. This designation exists because gases and vapors in air can ignite more easily, so electrical equipment used there must be designed and certified to prevent ignition. The other classes cover different ignition sources: Class II relates to combustible dust, and Class III to ignitable fibers. Class IV is not used for gas/vapor hazards in the standard classifications. So the presence of flammable vapors and gases points to Class I.

Environments with flammable gases or vapors are classified as Class I hazardous locations. This designation exists because gases and vapors in air can ignite more easily, so electrical equipment used there must be designed and certified to prevent ignition. The other classes cover different ignition sources: Class II relates to combustible dust, and Class III to ignitable fibers. Class IV is not used for gas/vapor hazards in the standard classifications. So the presence of flammable vapors and gases points to Class I.