Your Guide to Understanding NEMA Ratings and Enclosure Types

Last updated on July 3rd, 2023 at 06:46 pm

In 1926, the National Electric Manufacturers Association (NEMA) established a set of guidelines that determined electric equipment safety standards—including control panel enclosures. These enclosures protect against various hazards that may damage a temperature control panel or make it a hazard in itself. However, NEMA has created a rating system for different enclosure types. It’s crucial for industrialists to understand this system and use it as a guide when selecting an enclosure. 

Importance of fitting the right enclosure on a control panel 

Temperature control panels (often called digital control panels) give operators precise control over the temperature output of heating units, which prevents a medium from overheating. In many cases, they contain automatic shut-off switches, triggered when thermosensors detect excessively high temperatures. 

However, exposure to “the elements” can damage the control panel, inhibiting its performance and safety mechanisms. These hazards vary.

Elements that can damage temperature control panels

  • Corrosion
  • Dust, debris, fibers, and flyings (which can be flammable) 
  • Precipitation (rain, sleet, snow and so forth, if placed outdoors)
  • Water ingress
  • Falling objects

Direct exposure to these elements can damage control panels, leading to poor temperature control, and safety hazards, such as explosions. For these reasons, protecting your panels with the right enclosures is essential. 

NEMA ratings and enclosure types

When deciding what control panels to use, choose ones designated by the National Electric Manufacturers Association (NEMA). The organization has created ratings, which identify what types of hazards a particular enclosure protects against. Each rating goes by the designation “NEMA,” followed by a number.  


NEMA 1 enclosures are intended for indoor settings and are designed to protect control panels from solid falling debris, such as rocks and dirt. 


NEMA 2 enclosures offer the same level of protection as a Type 1, but with added protection against water ingress, dripping or light splashing.


NEMA 3 enclosures are suitable for indoor and outdoor settings and protect against solid objects, blowing dust, water ingress, and precipitation and ice.  


NEMA 3R enclosures are appropriate for indoor and outdoor settings and provide the same protection as NEMA 3 enclosures, minus the dust protection. 


NEMA 3RX enclosures protect against solid objects, water ingress and precipitation, ice and some corrosion resistance. They can be used indoors or outdoors and fitted with louvers and ventilation. 


NEMA 4 enclosures are designed for indoor and outdoor settings, offering protection against falling and blowing objects, water and precipitation, and ice. 


NEMA 4X enclosures offer the same protection as NEMA 4 options but also provide corrosion resistance. Also, like NEMA 4 enclosures, 4X options are suitable for indoor and outdoor settings. 


NEMA 5 enclosures offer identical protection to NEMA 4 enclosures but are meant for indoor use. However, they have reduced water protection and can’t remain submerged for extended periods. 


NEMA 6 enclosures provide identical protection to NEMA 4 options but with increased protection against short-term water immersion at a limited depth. There is a 6P version that allows for longer water submersion. 


NEMA 7 enclosures are designed for indoor settings deemed as hazardous locations. They are explosion-proof, shielding digital control panels from flammable dust, fibers, and flyings. 


NEMA 8 enclosures are also explosion-proof like NEMA 7 options but are suitable for indoor and outdoor use. 


NEMA 9 enclosures are also designed for hazardous locations, primarily indoor settings. They offer protection specifically against flammable dust particles. 


NEMA 11 enclosures are designed for indoor oil submersion, protecting control panels from corrosion stemming from oil exposure. They also shield temperature control panels from corrosive fumes and gas. 


NEMA 12 enclosures are designed to offer protection against solid objects and airborne particles such as flammable dust, fibers, and flyings. They also provide a measure of rust and water-resistance, and typically service indoor settings.

NEMA 13 

NEMA 13 enclosures are geared mainly for indoor use, offering identical protection to NEMA 12 options. However, they provide added resistance to the effects of oils and coolants. 

Choosing the right enclosure for your application 

Choosing the right enclosure for a temperature control panel boils down to your industrial application and the environment in which you operate. This is relatively straightforward—look at the placement of your temperature control panel and what it is exposed to. 

Once you know these hazards, the ideal NEMA enclosure should be fairly obvious. Of course, choosing the right enclosure might require additional thought, especially if there are multiple hazards and options for protection against these hazards.  

In such cases, you should always choose the NEMA enclosure that offers more protection than its less-abled counterpart. The more coverage you can provide your control panels, the less exposed they’ll be to multiple hazards. 

Wattco control panel options (NEMA certified) 

Aside from having NEMA-certified enclosures, it’s also vital for the temperature control panels themselves to be adequately constructed. In addition to a NEMA-rated enclosure, solid construction makes temperature control panels less susceptible to many of the abovementioned hazards.

Here at Wattco, we build temperature control panels with materials tested to withstand the harshest conditions. Our digital control panels come with various alarms and sensors that also present warnings and shut-offs, which further mitigates certain risks (i.e. fires, explosions). However, the risk of damage and hazardous situations is  low since we supply NEMA-rated enclosures to your panel as well. 

Get a quote for a temperature control panel and NEMA-rated enclosure today. Our representatives will help you find the exact setup needed for your industrial needs.