What do NEMA Enclosure Ratings Mean?
NEMA stands for National Electric Manufacturers Association. They have developed a set of standards for enclosures which house electrical components. We will outline 3 common types of enclosures.
NEMA-12 – Enclosures constructed (without knockouts) for indoor use to provide a degree of protection to personnel against access to hazardous parts; to provide a degree of protection of the equipment inside the enclosure against ingress of solid foreign objects (falling dirt and circulating dust, lint, fibers, and flyings). It contains a gasketed door to provide a degree of protection with respect to harmful effects on the equipment due to the ingress of water (dripping and light splashing).
NEMA-4 – Gasketed door enclosure intended for indoor or outdoor use primarily to provide a degree of protection against windblown dust and rain, splashing water, and hose directed water; undamaged by ice which forms on the enclosure.
NEMA-4X – Gasketed door enclosure intended for indoor or outdoor use primarily to provide a degree of protection against corrosion, windblown dust and rain, splashing water, and hose directed water; undamaged by ice which forms on the enclosure. This is the most common enclosure in “food” environments. Commonly made from stainless steel.