Journeyman Electrician’s Exam Journeyman Electrician's Hazardous Locations 2 — Questions and Answers
Question 1: Equipment installed in Class I, Division 1 locations must be listed as:
- Weatherproof only
- Dust-ignitionproof
- Explosion-proof or intrinsically safe (Correct answer)
- GFCI protected
Correct answer: Explosion-proof or intrinsically safe
Equipment in Class I, Division 1 must be explosion-proof, intrinsically safe, purged/pressurized, or another method approved by NEC Article 501.
Question 2: Threaded rigid metal conduit joints in Class I, Division 1 locations must have a minimum of how many threads fully engaged?
- 3 threads
- 5 threads (Correct answer)
- 7 threads
- 10 threads
Correct answer: 5 threads
NEC 501.10(A)(1) requires at least 5 threads fully engaged for threaded conduit joints in Class I, Division 1 to maintain explosion-proof integrity.
Question 3: Flexible connections in Class I, Division 1 locations must use:
- Standard liquid-tight flexible metal conduit
- Listed explosion-proof flexible fittings (Correct answer)
- Standard flexible metal conduit with bonding jumper
- PVC flexible conduit
Correct answer: Listed explosion-proof flexible fittings
Flexible connections in Class I, Division 1 require listed explosion-proof flexible fittings to maintain the required hazardous location rating.
Question 4: The primary purpose of sealing fittings in Class I hazardous locations is to:
- Prevent moisture from entering conduit
- Prevent passage of gases, vapors, or flames through the conduit system (Correct answer)
- Increase the mechanical strength of conduit joints
- Provide an equipotential bonding point
Correct answer: Prevent passage of gases, vapors, or flames through the conduit system
Seals prevent the passage of gases, vapors, or flames through the conduit system and minimize pressure piling from internal explosions per NEC 501.15.
Question 5: Which wiring method is generally NOT permitted in Class I, Division 2 locations?
- Rigid metal conduit (RMC)
- Intermediate metal conduit (IMC)
- Type MI cable
- Open wiring on insulators (Correct answer)
Correct answer: Open wiring on insulators
Open wiring on insulators exposes conductors to the hazardous atmosphere and is prohibited; enclosed wiring methods such as RMC, IMC, or listed cable assemblies are required.
Question 6: Per NEC 501.15(A)(1), sealing fittings must be installed within how many inches of an explosion-proof enclosure?
- 6 inches
- 12 inches
- 18 inches (Correct answer)
- 24 inches
Correct answer: 18 inches
Seals must be placed within 18 inches of explosion-proof enclosures to prevent the conduit from acting as a flame or pressure passage.
Question 7: The sealing compound used in Class I hazardous location seals must:
- Be any commercially available caulk rated for 300°F
- Not shrink or crack and be listed for the purpose (Correct answer)
- Be removable to allow future conductor changes
- Be installed only after all conductors are pulled
Correct answer: Not shrink or crack and be listed for the purpose
NEC 501.15(C)(2) requires sealing compound that will not shrink or crack and is listed for the purpose to permanently maintain seal integrity.
Journeyman Electrician’s Exam Journeyman Electrician's Hazardous Locations 2
Equipment installed in Class I, Division 1 locations must be listed as: