Special Occupancies & Hazardous Locations Flashcards

NEC Article 505 provides a 'Zone' classification system as an alternative to the Division system. This Zone system is primarily based on standards from which organization?

Answer: IEC (International Electrotechnical Commission)

The Zone classification system in NEC Article 505 is based on IEC standards, providing an internationally harmonized alternative to the North American Division system for Class I hazardous locations.

Per NEC 680.22(A)(3), all 125-volt receptacles located within 20 feet of the inside wall of a swimming pool must be protected by which device?

Answer: Ground-fault circuit interrupter (GFCI)

NEC 680.22(A)(3) requires GFCI protection for all 125V receptacles within 20 feet of the pool's inside walls to prevent electric shock hazards near water.

In Class I, Division 1 hazardous locations, threaded conduit connections must have at minimum how many threads fully engaged per NEC 501.10(A)(1)?

Answer: 5 threads

NEC 501.10(A)(1) requires threaded conduit connections in Class I, Division 1 locations to have a minimum of five fully engaged threads to maintain the explosion-proof flame path.

NEC Article 702 covers which type of standby electrical system?

Answer: Optional standby systems

Article 702 covers optional standby systems, which protect private business or residential operations but are not legally required for life-safety purposes.

Per NEC Article 680, which requirements apply to underwater luminaires installed in permanently installed swimming pools?

Answer: They must be listed for underwater use and GFCI protected

NEC 680.23 requires underwater luminaires to be listed for the purpose and GFCI protected to guard against shock hazards from submerged electrical equipment.

Which wiring method is generally NOT acceptable in Class I, Division 1 hazardous locations without special restrictions?

Answer: Standard flexible metal conduit (FMC) used as a general raceway

Standard flexible metal conduit cannot maintain the required explosion-proof sealing in Class I, Division 1 locations; only specifically listed flexible fittings for limited applications are permitted.

Per NEC 518.4, what wiring method is required for fixed wiring in projection booths within places of assembly covered by Article 518?

Answer: Metal raceways, Type MI cable, or Type MC cable

NEC 518.4 requires fixed wiring in projection booths and certain other areas in places of assembly to use metal raceways, Type MI cable, or Type MC cable due to elevated fire safety concerns.