When choosing an enclosure for your electrical device, having lots of options is great — but it’s equally important to know the key standards and ratings that will help you choose the right model. You need information about what kinds of hazards the electrical enclosure can resist and where it can be used. Fortunately, NEMA enclosure ratings offer an easy way to find that information.At Polycase, we are happy to leverage our expert knowledge of NEMA ratings and enclosure designs so that our customers can be confident that they know exactly what they’re looking for. Today, we’ll compare two of the most common and cost-effective types of enclosures: NEMA 1 enclosures and NEMA 3 enclosures. Each offers its own benefits at a competitive cost, and each can be a great option for the right application.

What Does a NEMA Rating Tell You?

The National Electrical Manufacturers Association (NEMA) has created the NEMA ratings system to help enclosure buyers find the model that offers the features and protection that they need. Their system rates an enclosure on the degree of protection that it provides to internal components against a variety of external hazards — from moisture to dust to corrosion. For more general information on NEMA enclosure ratings, check out the quick summaries of each NEMA type in our NEMA enclosure ratings guide. While you’re at it, see our IP ratings guide to get familiar with the other major enclosure ratings system that’s used to evaluate protective enclosures.

NEMA 1 Enclosures

NEMA 1 enclosures offer a good level of basic indoor protection for electrical and electronic devices.Pros:
  • Commonly used in environments that don’t require heavy-duty protection against dust or liquids but need a general purpose enclosure to prevent accidental contact
  • Protect against falling dirt
  • Cost-effective choice for less-demanding environments like offices, schools and retail establishments
Cons:
  • Probably not right for you if you need outdoor-grade weather protection, defense against oil and coolant splashing and seepage or substantial protection against airborne dust and fibers. For an outdoor enclosure, consider a NEMA 3, NEMA 4X or NEMA 6-rated model, while NEMA 12 enclosures offer a step up in indoor protection as well.
Polycase offers a full selection of NEMA 1 enclosures, all of which also feature ratings above NEMA 1 for improved performance and protection. Consider these models if you’re looking for a NEMA 1-rated indoor electronics enclosure:
  • WA Series: Durable ABS plastic and a silicone rubber gasket make the WA Series an outstanding option for indoor use.
  • WH Series: Tough polycarbonate or ABS construction, including hinges and latches, allow the WH Series to compete both indoors and outdoors.
Polycase WH-14

Polycase WH-14

NEMA 3 Enclosures

NEMA 3 enclosures are designed for outdoor use. They can be a cost-effective option for protecting electrical and electronic devices in an outdoor environment.Pros:
  • Divided into several sub-ratings to allow buyers to choose the features they need (We’ll discuss these below.)
  • Keeps out ingress of water from environmental conditions such as rain, snow and sleet, and also offers the protections of a NEMA 1 enclosure
  • Protects against damage from formation of ice on the enclosure’s exterior
  • Some NEMA 3 ratings offer dust-tight protection against windblown dust, dirt, flyings and debris
  • Typically lower price point than NEMA 4 or NEMA 6 enclosures
Cons :
  • Not a good choice if your device will be subjected to hose-directed water or submersion. Other ratings, like NEMA 4 and NEMA 6, offer a higher level of protection against additional hazards such as corrosion or submersion in water.
Each NEMA 3 sub-rating refers to specific protective features. These ratings are:
  • NEMA 3R: Can be ventilated but might not provide total protection against circulating dust and debris.
  • NEMA 3X and 3RX: Include built-in corrosion resistance to protect against corrosive forces such as salt water and industrial chemicals.
  • NEMA 3S and 3SX: Allow external mechanisms to be operated even if the enclosure is covered in ice.
Polycase customers will also find numerous NEMA 3 and NEMA 3R enclosure options in our selection. Some of our most popular NEMA 3 offerings (all of which are also rated to higher NEMA standards) are:
  • ZH Series: Super-tough hinged polycarbonate enclosures that offer a full range of accessories like pole-mounting kits and tamper-resistant screws.
  • HD Series: Great looking polycarbonate outdoor enclosures that meet every NEMA 3 series rating.
  • ZQ Series: Classic polycarbonate weatherproof enclosures with a screw-down lid and optional clear cover.
Polycase ZH-0604 Polycarbonate Enclosure

Polycase ZH-0604

Need more information about enclosure ratings, models, sizes and more? Give our NEMA enclosure experts a call at 1-800-248-1233 or contact us online for a free electronics enclosure quote on the products you need.
In NEMA Rated Enclosures