Question: what is the difference between nema 3 and 3r?
Answer: NEMA 3: For indoor or outdoor use. Same as NEMA 2 but adds stronger protection against the ingress of water and dust. It protects against windblown dust, rain, sleet, and snow and will be undamaged by ice forming on the enclosure. NEMA 3R: Same as NEMA 3 but without the protection against windblown dust.