NEC classification of hazardous locations and the equipment requirements for each class and division, tested on licensing exams.
25 cards · basic cards · AI-written, checked twice. Edit anything.
- What is a Class I hazardous location?
- An area where flammable gases, vapors, or mists that can form explosive atmospheres are or may be present.
- What is a Class II hazardous location?
- An area where combustible dust is or may be present in sufficient quantity to create an explosion hazard.
- What is a Class III hazardous location?
- An area where easily ignitable fibers or flyings are present but not suspended in sufficient quantity to create an explosion hazard.
- In Class I Division 1, when is the explosive atmosphere present?
- Under normal operating conditions.
- In Class I Division 2, when is the explosive atmosphere present?
- Only during abnormal operating conditions or as a result of infrequent maintenance.
- In Class II Division 1, when is combustible dust present?
- During normal operations or as a result of routine processing.
- In Class II Division 2, when is combustible dust present?
- Only during abnormal conditions or as a result of infrequent maintenance.
- In Class III Division 1, what condition exists?
- Easily ignitable fibers or flyings are actively handled, manufactured, or stored.
- In Class III Division 2, what condition exists?
- Easily ignitable fibers or flyings are stored but not being handled or manufactured.
- What is Zone 0?
- An area where an explosive atmosphere is present continuously, or for long periods, or frequently.
- What is Zone 1?
- An area where an explosive atmosphere is likely to occur in normal operation, or frequently present.
- What is Zone 2?
- An area where an explosive atmosphere is unlikely in normal operation and, if it occurs, only infrequently and for short periods.
- What primary protection method must equipment use in Class I hazardous locations?
- Explosionproof construction or intrinsically safe design to contain any internal explosion.
- What primary protection method must equipment use in Class II hazardous locations?
- Dust-tight construction to prevent dust infiltration and minimize dust collection on internal surfaces.
- What protection is required for equipment in Class III hazardous locations?
- Dust-tight construction to minimize fiber collection on internal surfaces and prevent ignition of accumulated fibers.
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