Journeyman Electrician's Hazardous Locations Flashcards
7 cards from real Journeyman Electrician’s Exam practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
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What type of hazardous material defines a Class I hazardous location?
Answer: Flammable gases or vapors
Class I locations are those where flammable gases or vapors may be present in quantities sufficient to produce explosive or ignitable mixtures.
In a Class I, Division 1 location, ignitable concentrations of flammable gas exist:
Answer: Under normal operating conditions
Division 1 means ignitable concentrations exist under normal operating conditions, during repair or maintenance, or due to equipment breakdown.
Class II hazardous locations are defined by the presence of:
Answer: Combustible dusts
Class II locations are hazardous because of the presence of combustible dust that can form ignitable mixtures with air.
Class III hazardous locations involve which type of hazardous material?
Answer: Easily ignitable fibers or flyings
Class III locations are hazardous because of the presence of easily ignitable fibers or flyings that are handled, manufactured, or used.
Which NEC article covers Class I hazardous locations using the Zone classification system?
Answer: Article 505
NEC Article 505 covers Class I, Zone 0, Zone 1, and Zone 2 hazardous locations as an alternative to the Division system in Article 500.
In a Class II, Division 1 location, combustible dust is present:
Answer: In suspension or dangerous accumulations under normal conditions
Division 1 for Class II means ignitable dust concentrations may be in suspension or form dangerous accumulations under normal operating conditions.
A grain elevator storage area would most typically be classified as:
Answer: Class II, Division 1
Grain elevators contain combustible grain dust that is routinely suspended in air under normal operations, making them Class II, Division 1.