Select Page

Amazon Type A – 2019-08-16T113227.146

NEMA 250

NEMA 250 addresses the ingress protection of enclosures for electrical equipment rated at 1000 Volts or less and intended to be installed and used in specific non-hazardous and hazardous locations. NEMA 250 has defined 20 different enclosure types.

The enclosures are grouped by hazardous and non-hazardous locations as well as indoor, outdoor and mining. Below is a summary of each category and its specific enclosures:

Non-Hazardous (unclassified) locations NEMA 250 Enclosures:

  • Indoor locations, Types 1, 2, 5, 12, 12K and 13.
  • Indoor or outdoor locations, Types 3, 3X, 3R, 3RX, 3S, 3SX, 4, 4X, 6 and 6P.

Hazardous (classified) locations NEMA 250 Enclosures:

  • Enclosures for indoor locations, Types 7 and 9.
  • Enclosures for indoor or outdoor locations, Type 8.
  • Enclosures for mining applications, Type 10.

Keystone Compliance is a certified NEMA 250 testing lab. What sets Keystone Compliance’s NEMA testing apart is our experience in helping manufacturers determine ingress points in their products and also identifying potential solutions. We also have significant expertise in interpreting the NEMA 250 standard. Just because some liquid or dust may enter an enclosure, does not automatically mean that the unit has not met the requirements. If the unit that requires testing is too large to move, no problem. We have experience completing ingress protection testing at the customer’s facilities.

Why is Keystone Compliance the right NEMA 250 ingress protection lab to complete your ingress testing? Our customers enjoy our short lead times, ability to explain the process and testing requirements, consultative engineering support when failures occur and affordable pricing. Contact us to receive a quote for ingress protection testing and see why we are the only ingress protection lab for so many manufacturers from around the country.

Click on the tabs below for more information on each of the 20 types of NEMA 250 enclosures:

NEMA Type 1

NEMA 250 Type 1 enclosures are defined as enclosures constructed for indoor use. These enclosures provide a degree of protection to personnel against access to hazardous parts and provide a degree of protection of the equipment inside the enclosure against ingress of solid foreign objects such as falling dirt. For more information, please visit our NEMA 250 Type 1 enclosure testing page.

NEMA Type 2

NEMA 250 Type 2 enclosures are constructed for indoor use. These enclosures provide a degree of protection to personnel against access to hazardous parts. They also provide a degree of protection of the equipment inside the enclosure against the ingress of solid foreign objects such as falling dirt. Lastly, these enclosures provide a degree of protection with respect to the harmful effects on the equipment due to the ingress of dripping water and light splashing water. For more information, please visit our NEMA Type 250 enclosure testing page.

NEMA Type 3

NEMA 250 Type 3 enclosures are constructed for either indoor or outdoor use. These enclosures provide a degree of protection to personnel against access to hazardous parts. They also provide a degree of protection of the equipment inside the enclosure against ingress of solid foreign objects such as falling dirt and windblown dust. These NEMA enclosures also provide a degree of protection with respect to harmful effects on the equipment due to the ingress of water from rain, sleet, or snow. To be classified NEMA 250 Type 3, the enclosure must be undamaged by the external formation of ice on the enclosure. For more information, please visit our NEMA 250 Type 3 enclosure testing page.

NEMA Type 3R

NEMA 250 Type 3R enclosures are constructed for either indoor or outdoor use to provide a degree of protection to personnel against access to hazardous parts. These enclosures provide a degree of protection of the equipment inside the enclosure against ingress of solid foreign objects such as falling dirt. They also provide a degree of protection with respect to the harmful effects on the equipment due to the ingress of water from events such as rain, sleet or snow. The enclosure must remain undamaged by the external formation of ice on the enclosure. For more information, please visit our NEMA 250 Type 3R enclosure testing page.

NEMA Type 3S

NEMA 250 Type 3S enclosures are constructed for either indoor or outdoor use to provide a degree of protection to personnel against access to hazardous parts. These enclosures provide a degree of protection of the equipment inside the enclosure against ingress of solid foreign objects  such as falling dirt and windblown dust. They also provide a degree of protection with respect to harmful effects on the equipment due to the ingress of water such as rain, sleet or snow. NEMA 250 Type 3S enclosures also must permit any external mechanism(s) to remain operable when ice laden. For more information, please visit our NEMA 250 Type 3S enclosure testing page.

NEMA Type 3X

NEMA 250 Type 3X enclosures are constructed for either indoor or outdoor use to provide a degree of protection to personnel against access to hazardous parts. These enclosures provide a degree of protection of the equipment inside the enclosure against ingress of solid foreign objects including falling dirt and windblown dust. These NEMA enclosures provide a degree of protection with respect to harmful effects on the equipment due to the ingress of rain, sleet and snow. Type 3X containers provides an increased level of protection against corrosion and must be undamaged by the external formation of ice on the enclosure. For more information, please visit our NEMA Type 3X enclosure testing page.

NEMA Type RX

NEMA 250 Type 3RX enclosures are constructed for either indoor or outdoor use to provide a degree of protection to personnel against access to hazardous parts. These NEMA containers provide a degree of protection of the equipment inside the enclosure against ingress of solid foreign objects like falling dirt. They provide a degree of protection with respect to harmful effects on the equipment due to the ingress of rain, sleet or snow. NEMA Type 3RX enclosures must be undamaged by the external formation of ice on the enclosure and provide an increased level of protection against corrosion. For more information, please visit our NEMA 250 Type 3RX enclosure testing page.

NEMA Type 3SX

NEMA 250 Type 3SX enclosures are constructed for either indoor or outdoor use to provide a degree of protection of the equipment inside the enclosure against ingress of solid foreign objects such as falling dirt and windblown dust. These enclosures provide a degree of protection with respect to harmful effects on the equipment due to the ingress of water from rain, sleet or snow. They also provide an increased level of protection against corrosion. These enclosures must permit any external mechanism(s) to remain operable when ice laden. For more information, please visit our NEMA 250 Type 3SX enclosure testing page.

NEMA Type 4

NEMA 250 Type 4 enclosures are constructed for either indoor or outdoor use. These enclosures provide a degree of protection to personnel against access to hazardous parts. They also provide a degree of protection of the equipment inside the enclosure against ingress of solid foreign objects. Examples would be falling dirt and windblown dust. These enclosures  provide a degree of protection with respect to harmful effects on the equipment due to the ingress of liquid such as rain, sleet, snow, splashing water and hose directed water. Lastly, Type 4 enclosures must be undamaged by the external formation of ice on the enclosure. For more information, please visit our NEMA 250 Type 4 enclosure testing page.

NEMA Type 4X

NEMA 250 Type 4X enclosures are constructed for either indoor or outdoor use to provide a degree of protection to personnel against access to hazardous parts. These enclosures provide a degree of protection of the equipment inside the enclosure against ingress of solid foreign objects such as falling dirt and windblown dust. They also provide a degree of protection with respect to harmful effects on the equipment due to the ingress of water from rain, sleet, snow, splashing water and hose directed water. Lastly, these enclosures provide an increased level of protection against corrosion and must remain undamaged by the external formation of ice on the enclosure. For more information, please visit our NEMA 250 Type 4X enclosure testing page.

NEMA Type 5

NEMA 250 Type 5 enclosures are constructed for indoor use to provide a degree of protection to personnel against access to hazardous parts. These enclosures provide a degree of protection of the equipment inside the enclosure against ingress of solid foreign objects such as falling dirt and settling airborne dust, lint, fibers and flyings. They also provide a degree of protection with respect to harmful effects on the equipment due to the ingress of dripping water and light splashing water. For more information, please visit our NEMA 250 Type 5 enclosure testing page.

NEMA Type 6

NEMA 250 Type 6 enclosures are constructed for either indoor or outdoor use to provide a degree of protection to personnel against access to hazardous parts. The enclosures provide a degree of protection of the equipment inside the enclosure against ingress of solid foreign objects like falling dirt. They provide a degree of protection with respect to harmful effects on the equipment due to the ingress of water such as hose directed water and the entry of water during occasional temporary submersion at a limited depth. Type 6 enclosures must be undamaged by the external formation of ice on the enclosure. For more information, please visit our NEMA 250 Type 6 enclosure testing page.

NEMA Type 6P

NEMA 250 Type 6P Enclosures constructed for either indoor or outdoor use to provide a degree of protection to personnel against access to hazardous parts. These enclosures provide a degree of protection of the equipment inside the enclosure against ingress of solid foreign objects like falling dirt. They provide a degree of protection with respect to harmful effects on the equipment due to the ingress of hose directed water and the entry of water during prolonged submersion at a limited depth. These enclosures provide an increased level of protection against corrosion and are undamaged by the external formation of ice on the enclosure. For more information, please visit our NEMA 250 Type 6P enclosure testing page.

NEMA Type 7

NEMA 250 Type 7 enclosures, when properly installed and maintained, are designed to contain an internal explosion without causing an external hazard. Hazardous (classified) locations, other than in mines, are classified according to the flammability or combustibility of the materials that may be present. Also considered is the likelihood that a flammable or combustible concentration being present. For more information, please visit our NEMA 250 Type 7 enclosure testing page.

NEMA Type 8

NEMA 250 Type 8 enclosures are designed to prevent combustion through the use of oil-immersed equipment. Hazardous  locations (other than in mines) are classified according to the flammability or combustibility of the materials that may be present and also according to the likelihood that a flammable or combustible concentration is present. For more information, please visit our NEMA 250 Type 8 enclosure testing page.

NEMA Type 9

NEMA 250 Type 9 enclosures are constructed for indoor use in hazardous (classified) locations classified as Class II, Division 1, Groups E, F, or G as defined in NFPA 70. These enclosures must provide a degree of protection against atmospheres typically containing the following metal dust, carbon black, coal dust, coke dust, flour, starch, grain dust, fibers and flyings. For more information, please visit our NEMA 250 Type 9 enclosure testing page.

NEMA Type 10

NEMA 250 Type 10 enclosures are constructed to meet the requirements of the Mine Safety and Health Administration, 30 CFR, Part 18. These enclosures must provide a degree of protection against atmospheres typically containing methane with or without coal dust. For more information, please visit our NEMA 250 Type 10 enclosure testing page.

NEMA Type 12

NEMA 250 Type 12 enclosures are constructed without knockouts. They are for indoor use to provide a degree of protection to personnel against access to hazardous parts. These enclosures provide a degree of protection of the equipment inside the enclosure against ingress of solid foreign objects such as falling dirt and circulating dust, lint, fibers and flyings. Type 12 enclosures provide a degree of protection with respect to harmful effects on the equipment due to the ingress of dripping and light splashing water. They also provide a degree of protection against light splashing and seepage of oil and noncorrosive coolants. For more information, please visit our NEMA 250 Type 12 enclosure testing page.

NEMA Type 12K

NEMA 250 Type 12K enclosures are constructed with knockouts for indoor use. They provide a degree of protection to personnel against access to hazardous parts. These enclosures provide a degree of protection of the equipment inside the enclosure against ingress of solid foreign objects like falling dirt and circulating dust, lint, fibers, and flyings. They provide a degree of protection with respect to harmful effects on the equipment due to the ingress of water (dripping and light splashing). They also provide a degree of protection against light splashing and seepage of oil and non-corrosive coolants. For more information, please visit our NEMA 250 Type 12K enclosure testing page.

NEMA Type 13

NEMA 250 Type 13 enclosures are constructed for indoor use. They provide a degree of protection to personnel against access to hazardous parts. They also provide a degree of protection of the equipment inside the enclosure against ingress of solid foreign objects such as falling dirt and circulating dust, lint, fibers, and flyings. Type 13 enclosures provide a degree of protection with respect to harmful effects on the equipment due to the ingress of dripping and light splashing water. They also provide a degree of protection against the spraying, splashing, and seepage of oil and non-corrosive coolants. For more information, please visit our NEMA 250 Type 13 enclosure testing page.