The NEMA ratings indicate the level of protection the device's enclosure provides. The ratings available with Ranco ETC controllers are outlined below. For complete definitions, descriptions and test criteria, see the National Electrical Manufacturers Association (NEMA) Standards Publication No. 250

NEMA 1 – Enclosures constructed for indoor use to provide a degree of protection to personnel against incidental contact with the enclosed equipment and to provide a degree of protection against falling dirt.

NEMA 4 – Enclosures constructed for either indoor or outdoor use to provide a degree of protection to personnel against incidental contact with the enclosed equipment; to provide a degree of protection against falling dirt, rain, sleet, snow, windblown dust, splashing water, and hose-directed water; and that will be undamaged by the external formation of ice on the enclosure. Note: this is not an explosion proof enclosure.

NEMA 4X – Same as NEMA 4 including protection against corrosion.

Ranco ETC Models ETC-141000-000 and ETC-241000-000 have a NEMA 4X rated enclosure. All others have a NEMA 1 enclosure