Info

NEMA type ratings for hazardous and industrial locations

NEMA enclosure types, as defined by NEMA 250, are the primary standard used to specify environmental protection for electrical and electronic equipment enclosures.

NEMA ratings are widely referenced in NEC (NFPA 70) installations and are commonly required for:

  • UL-listed equipment
  • Industrial control equipment
  • Fire alarm and signaling devices
  • Hazardous location applications

Equipment may carry multiple NEMA ratings, depending on its construction and certified environmental protection.

In hazardous locations, the NEMA enclosure rating complements but does not replace hazardous location protection methods such as:

  • Explosion-proof (XP) design
  • Intrinsically safe (IS) design
Enclosure Types According to NEMA 250
Type of Enclosure 1 2 3 3X 3R 3RX 3S 3SX 4 4X 5 6 6P 12 12K 13
Indoor use • • • • • • • • • • • • • • • •
Outdoor use • • • • • • • • • •
Access to hazardous parts • • • • • • • • • • • • • • • •
Ingress of solid foreign objects (falling dirt) • • • • • • • • • •
Ingress of solid foreign objects (windblown dust, lint, fibres and flyings) • • • • • • • •
Ingress of water (dripping, light splashing) • • • • • • • • •
Ingress of solid foreign objects (circulating dust, lint, fibres and flyings) • • • • • • •
Ingress of solid foreign objects (settling airborne dust, lint, fibres and flyings) • • • • • • • •
Ingress of water (hosedown and splashing water) • • • •
Oil and coolant seepage • • •
Oil and coolant spraying and splashing •
Corrosive agents • • • • •
Ingress of water (occasional temporary submersion) • •
Ingress of water (occasional prolonged submersion) •
Ingress of water (rain, snow and sleet) • • • • • • • • •
External mechanisms operable when ice laden • •