Which NEMA enclosure type is approved for general indoor use and is NOT dust-tight or drip-proof?

• A. Type 3R
• B. Type 12
• C. Type 1
• D. Type 4X

Answer: (A)

NEMA enclosure ratings tell you what environments an enclosure can safely be used in and what protections it provides. A Type 3R enclosure is designed for indoor or outdoor use and offers protection against falling rain, but it is not dust-tight and not drip-proof. That combination fits the requirement of general indoor use while not providing dust-tight or drip-proof protection. The other types add protections for dust or water in ways that exceed what the question asks (dust-tight or drip-proof features, or specialized indoor/outdoor use), so they don’t fit as well.