Which NEC article covers the use of electrical equipment in corrosive environments?

• A. Article 300.
• B. Article 725.
• C. Article 410.
• D. Article 500.

Answer: (D)

Corrosive environments are considered hazardous locations for electrical equipment, because the atmosphere can cause damage to equipment or create unsafe conditions. The NEC keeps the rules for using and installing equipment in these special places in a single chapter: Article 500, which covers Hazardous (Classified) Locations. This article defines how such locations are classified and what equipment ratings, enclosure types, and installation practices are required when corrosive atmospheres are present. The other articles mentioned focus on different topics—general wiring methods (not specific to hazardous or corrosive environments), signaling/power-limited circuits, and lighting equipment—so they don’t address the special requirements for corrosive environments. That makes Article 500 the right place for guidance on equipment use in corrosive atmospheres.