Journeyman Electrician Exam (NEC)Special Occupancies, Equipment, and ConditionsHard
A Class I, Division 2 hazardous location contains a permanently installed luminaire. The luminaire is not intrinsically safe. According to NEC Article 500, which of the following is an acceptable method of protection for this luminaire?
- AHermetically sealed
- BPurged and pressurized
- COil immersion
- DEncapsulation
Show answer & explanationAnswer & explanation
Correct answer: B. Purged and pressurized
NEC Article 500 provides various protection techniques for equipment in hazardous locations. For Class I, Division 2 locations, acceptable methods include explosionproof enclosures, purged and pressurized enclosures, or nonincendive circuits/equipment. Option C, 'Purged and pressurized', is a recognized method for protecting electrical equipment in such environments, preventing the entry of hazardous gases or vapors.
Why the other options are wrong
- A. Hermetically sealed devices are not specifically listed as a primary protection method for Class I, Division 2 locations in the NEC, though components might be.
- C. Oil immersion is a protection method, but is typically for Class I, Division 1, and not commonly used for luminaires in Division 2.
- D. Encapsulation is a protection method, but it is typically for Class I, Zone 0/1 or Class II/III, and not the primary method specified for Division 2 luminaires without other considerations.
Hazardous Location Protection Methods
Techniques used to prevent ignition of flammable atmospheres by electrical equipment in hazardous (classified) locations, as defined by NEC Article 500.
- Methods vary by Class, Division, and Zone.
- Aims to contain explosions, prevent ignition, or limit energy.
- Examples: explosionproof, purged/pressurized, intrinsic safety.
Memory trick: Class I Division 2, keep the fumes out, pressurize through and through.