What type of NEMA enclosure provides a degree of protection against windblown dust?

The option indicating Type 3 enclosure is correct because NEMA Type 3 enclosures are specifically designed to provide a degree of protection against windblown dust as well as water. These enclosures are suitable for outdoor use where exposure to the elements is possible, helping to ensure that internal components remain safe from dust ingress and moisture, which could otherwise lead to functional issues or equipment failure.

Type 3 enclosures typically feature reinforced covers and gaskets to minimize openings and enhance sealing, making them effective in environments where dust and rain may be prevalent. This specification allows electrical equipment housed within to perform reliably in industrial or commercial applications where exposure to both dust and moisture is a concern.

In contrast, other types such as Type 1 offer minimal protection suitable for indoor use, while Type 3R provides similar benefits but specifically for rain without dust protection. Type 4 offers robust protection against water and dust, but it goes beyond what is necessary for situations where windblown dust is the primary concern, making Type 3 the most appropriate choice for that specific scenario.