Special Occupancies: Hazardous (Classified) Locations (500/501), Commercial Garages (511), Health Care (517) and Assembly (518)
The "Special Occupancies" sub-topic on the Texas exams draws mostly from four places: the Class/Division/Group vocabulary of Article 500, the seal rules of 501.15, the garage classification table of 511.5, the patient-care wiring rules of 517.13–517.19, and the assembly-occupancy wiring methods of 518.6. Written from the 2026 text.
NFPA 70 National Electrical Code, 2026 edition · Reviewed 2026-09-19
The "Special Occupancies" sub-topic on the Texas exams draws mostly from four places: the Class/Division/Group vocabulary of Article 500, the seal rules of 501.15, the garage classification table of 511.5, the patient-care wiring rules of 517.13–517.19, and the assembly-occupancy wiring methods of 518.6. Written from the 2026 text.
1. Hazardous (classified) locations — Article 500
- Classes: Class I — flammable gases, flammable liquid-produced vapors or combustible liquid-produced vapors; Class II — combustible dust; Class III — easily ignitible fibers or flyings (not normally in suspension).
- Divisions: Division 1 — ignitible concentrations exist under normal operation, or frequently because of repair/maintenance/leakage, or where equipment breakdown might release them and simultaneously fail electrical equipment as an ignition source. Division 2 — materials normally confined in closed containers/systems and escape only by accident or abnormal operation; concentrations normally prevented by positive mechanical ventilation that might fail; or adjacent to a Division 1 location from which vapors might occasionally be communicated.
- Groups (500.6): Class I — Group A (acetylene), Group B (hydrogen — MESG ≤ 0.45 mm), Group C (ethylene — MESG > 0.45 to ≤ 0.75 mm), Group D (propane — MESG > 0.75 mm); Class II — Group E (combustible metal dusts: aluminum, magnesium), Group F (carbonaceous dusts: carbon black, coal, coke), Group G (other combustible dusts: flour, grain, wood, plastics, chemicals).
- 500.7 protection techniques: explosionproof (Class I Div 1/2); dust-ignitionproof (Class II Div 1/2); dusttight (Class II Div 2, Class III); purged and pressurized (any, NFPA 496); intrinsic safety (all classes, Div 1/2 — Article 504); nonincendive circuits/equipment/ components, oil immersion and hermetically sealed (Division 2 only); combustible gas detection in industrial establishments with qualified persons — lets a Division 1 area be classified Division 2, a building interior adjacent to Division 2 be unclassified, and a Division 1 panel interi
This is where the public part ends.
The rest of this lesson, its quiz, all 6 lessons in the module and every mock exam open with the 7-day pass for $9. If you stay, it comes off lifetime.