NEMA 3 and NEMA 3R Electronics Enclosure

There are several electrical devices and equipment installed outdoors and most of the people do not even notice. From the junction boxes to electricity transformers, all of these are protected by an enclosure. For design engineers, they are fully knowledgeable about how much is happening in the background. Engineers know that our electrical devices are what keeps and maintains our comfortable lifestyle. However, to protect these devices, the engineer should choose the proper electrical enclosure.


With this in mind, which is the NEMA rated electronics enclosure cabinets are considered weatherproof?

Commonly, these are the NEMA rating ideal for weatherproof applications:

  • NEMA 3 and its subsets
  • NEMA 4 and NEMA 4X
  • NEMA 12

But for this article, we will discuss NEMA 3 and its subset, NEMA 3R.

What are NEMA 250 type 3 rating?

NEMA 3 enclosures are manufactured and designed to protect household electrical controls, rotating equipment, generator skids. Also, it protects electrical types of equipment used and aboard ship docks, construction sites and even equipment used in subway systems or tunnels.


These are the main hazards NEMA 3 protects the personnel and electronic equipment from:

  • Accidental personnel contact
  • Solid protection from dust and airborne particles
  • Water ingress protection from rain, sleet
  • Ice formation protection


NEMA 3’s common applications are for:

  • Circuit breaker and boxes
  • Junction boxes
  • Security systems
  • Farming equipment
  • Air conditioning or heating equipment
  • A/V systems installed outdoors
  • Utility meters

What are NEMA 250 type 3R rating?

NEMA 3R enclosures are designed for both indoor or outdoor nonhazardous applications. It offers protection for equipment as type 3 indicated above. These features might seem to be ideal to withstand regular weather conditions, this is not always the case. Heavy rainfall can cause water ingress into the enclosure.


NEMA 3R is the best and smart choice for design engineers for their rain resistant applications. Depending on the material used for fabrication and project applications, NEMA 250 type 3R is a cost-effective enclosure to be used for regular weather conditions. These are commonly found in residential, commercial, and some industrial applications.


The biggest advantage of NEMA 3R rating is that it can be used to protect equipment from weather conditions at a very low cost. It should be noted that the cost of an enclosure still depends on what material is used to fabricate the cabinet and the costs that come with it.


Type 3r has a good range of different applications. This enclosure has been utilized for the safety switches found in homes and apartments. It also protects and houses electronic equipment found in a mobile power system distribution.