Weatherproof NEMA Enclosures: Choosing Between NEMA 3, 4X, or 6P Rated Enclosures

Weatherproof NEMA Enclosures

Many outdoor electrical devices are easy for the average person to forget about. The professionals who work on these devices, however, know just how much is going on in the background. They know that from junction boxes and breakers to home air conditioning units, we depend on these units every day to keep our world humming along. A major reason why our outdoor electrical units are as dependable as they are? They’re protected by electrical enclosures designed and built to withstand the punishment nature can throw at them.  

It can be challenging to create an enclosure that meets these demanding specs, but at Polycase, we’ve never been afraid of a challenge. Polycase uses the NEMA enclosure rating system to ensure that our electrical enclosures provide the performance our customers demand. We offer weatherproof models in three NEMA categories: NEMA 3, NEMA 4X and NEMA 6P.

What can a NEMA rating tell you about which enclosure is right for your needs? What’s the difference between the three weatherproof NEMA categories, and what kinds of options does Polycase offer in each? We’re here to answer your questions!

What Information Is in a NEMA Rating?

The National Electrical Manufacturers Association, or NEMA, created the widely-used NEMA enclosure rating system to define performance standards for electrical enclosures. A NEMA rating provides vital information on how well an enclosure resists many common environmental hazard categories. These include, but aren’t limited to:

NEMA Rating Infographic

  • Accidental employee contact with hazardous parts
  • Free-floating or settling dust, lint or other small debris
  • Weather such as rain, sleet or snow
  • Splashing, dripping or hose-directed water
  • Ice formation on the outside of the enclosure
  • Partial or complete submersion

Any of these hazards can cause serious issues for mission critical electronic assets. That’s why it’s essential to choose a NEMA-rated enclosure that’s right for a device’s intended use. A Polycase enclosure manufactured to the correct NEMA standards will stand up to the environmental hazards present and provide a long life for your device.

However, there are some important limits to what a NEMA rating can tell you. NEMA ratings are voluntary and self-certified, and NEMA does not test products or offer a seal of approval. Thus, a NEMA rating by itself unfortunately can’t guarantee that a product will offer the specifications it claims.

The easiest way to ensure your enclosures are up to spec is to look for NEMA ratings that have been approved by Underwriters Laboratories (UL). UL is another safety standards organization that uses safety standards similar to NEMA. Unlike NEMA, however, they require testing before allowing their ratings to be used.

Achieving a UL NEMA rating requires extensive product testing and a site visit from UL’s trained inspectors. Only enclosures that have a UL NEMA rating should be safely considered NEMA-compliant—which is why you’ll find these ratings on Polycase’s enclosures. We strive to give our customers the ultimate confidence in our product at every opportunity.

Now that we’ve cleared that up, we can start to dig in. First up: Which exact NEMA ratings will we be dealing with here?

Which NEMA Ratings Are Considered Weatherproof?

The three NEMA ratings recommended for general outdoor use are as follows:

  • NEMA Type 3 and its several variants
  • NEMA Type 4 and 4X
  • NEMA Type 6 and 6P

Enclosures in these rating categories are all considered “weatherproof” to varying degrees. When properly mounted and installed, these enclosures all offer significant protection against rain, sleet and snow. However, there are also differences that will affect which enclosure type meets the needs of your ideal solution.

Now it’s time to dive into some detail about the enclosure types. We’ll examine what makes each one useful and then take a look at Polycase’s selection of weatherproof enclosures.

NEMA 3 Enclosures

The NEMA 3 rating category is the first of three categories rated for outdoor use. The main hazards that NEMA 3 enclosures protect against include:

  • Accidental contact
  • Dust and airborne particles
  • Rain, sleet and snow
  • Ice formation on the outside of the enclosure

NEMA 3 is a large category that includes several variants: Type 3X, 3R, 3S, 3RX and 3SX. Each includes small but potentially important differences in protection:

NEMA 3R and 3rx

  • NEMA 3S- and 3SX-rated enclosures are a special subtype that allow any external equipment to be operated while the device is obstructed with ice. These subtypes are the only NEMA ratings that offer this feature.
  • NEMA 3R– and 3RX-rated enclosures do not require the gasket that other models in this category have. This increases their vulnerability to dust and particles but makes them a cost-effective solution in environments that don’t require complete particulate protection.
  • NEMA 3X-, 3RX- and 3SX-rated enclosures offer superior resistance to mild corrosive agents such as salt spray.

You’ll find NEMA 3-rated enclosures in use across a great variety of fields. Some of their most common applications include:

  • Circuit breaker boxes
  • Utility meters
  • Outdoor security systems
  • Farm equipment
  • Junction boxes
  • Heating and air conditioning equipment
  • Outdoor A/V systems

Polycase offers numerous durable and cost-effective NEMA 3-rated enclosure models. However, our specialty is exceeding expectations, and almost all of these models are also rated at NEMA 4 or 4X! What does this extra level offer? All of the same benefits, plus important extra protection.

NEMA 4 and NEMA 4X Enclosures

NEMA 4- and 4X-rated enclosures are similar in most ways to NEMA 3-rated ones, but they add one key difference: a resistance to hose-directed water. That makes them ideal for areas that get frequent hose-downs, including:

  • Food and beverage back-of-house areas
  • Breweries and distilleries
  • Some medical facilities
  • Car washes
  • Greenhouses and other horticultural facilities
  • Livestock processing facilities

A NEMA 4X-rated enclosure also protects its contents from corrosion, but its advanced waterproofing often makes it a better choice for marine applications than the NEMA 3X. For instances in which corrosion and hose-spray protection is desirable but submersion is not a relevant hazard, a NEMA 4X-rated enclosure can be a great choice.

However, sometimes anything less than maximum protection won’t get the job done. When environmental conditions demand complete watertight performance, up to and including potential submersion, you need to step up to the top-level defense of NEMA Type 6/6P enclosures.

NEMA Type 6 and 6P Enclosures

NEMA 6 and 6p

A NEMA 6- or 6P-rated enclosure ranks among the most durable and watertight protection that an electronic device can have. The 6 and 6P ratings offer all of the same weatherproofing features of a 4 or 4X enclosure, but add protection against:

  • Occasional temporary submersion (Type 6)
  • Occasional prolonged submersion (NEMA Type 6P)

These enclosures are the toughest of the tough and can ride out some of the most extreme environmental conditions. But even in environments where submersion isn’t likely, a NEMA 6 enclosure can offer great peace of mind. Some of the many applications of a Polycase NEMA 6/6P enclosure include:

  • Wastewater treatment and distribution facilities
  • Energy grid equipment
  • Maritime equipment such as boats, ships and offshore rigs
  • Outdoor electronics in flood-prone areas
  • Wildlife monitoring devices

These three enclosure types represent the majority of outdoor-rated electrical enclosures. You’ll need to determine for yourself which one best suits your needs. However, there are some other common ratings and systems you should be aware of when making your selection.

Other Common Ratings (NEMA and Otherwise)

Of course, the enclosure classification systems don’t stop with those three NEMA ratings. First, NEMA provides a variety of other enclosure ratings, both for indoor enclosures and for specialty models intended for specific use cases:

  • NEMA Types 1, 2, 5, 12 and 13 are intended for indoor applications. They can provide substantial protection, but generally aren’t recommended for outdoor use.
  • NEMA Types 7, 8 and 9 are specialty ratings for use in hazardous indoor environments. This includes some types of mine, chemical processing plants and oil and gas facilities.

SG Series from Polycase

You should also consider several enclosure rating scales besides NEMA ratings:

  • If flame resistance is a concern, look into the UL flammability rating scale. Polycase offers several enclosure models rated UL94-5VA, the most flame-resistant rating on the scale.
  • Those with international interests should consider using the IP rating system alongside NEMA ratings. Unlike NEMA, whose standards are applied largely in the U.S., the IP system is internationally recognized.
  • For impact resistance, look for enclosures with IK ratings, the international scale used to measure impact protection. The SG Series from Polycase offers an IK08 rating thanks to its tough polycarbonate construction.

Our Weatherproof NEMA Selection

At Polycase, our focus is on one thing: ensuring that our customers have the optimal tools with which to execute their vision. That’s why we offer an extensive array of UL NEMA-rated devices with many different levels of protection and price points.

It’s worth devoting some time to our full weatherproof NEMA enclosure selection to take it all in and find the perfect solution for you. However, here are some of our most popular options to consider:

  • NEMA 3 and NEMA 4/4X
  • NEMA 6/6P
    • Polycase’s NEMA 6/6P-rated offerings include our rugged YH Series. The YH Series is molded from high-quality polycarbonate and is ideal for a pole-mounted electrical enclosure. These models include a corrosion-resistant plastic hinge and are available with gray or clear covers.
    • Our HD Series offers another classic option–it’s injection-molded from sturdy polycarbonate  plastic and features surface-mounting flanges.
    • The AN Series is diecast aluminum and offers watertight NEMA 6P protection with power performance to match its sleek aesthetic.

Polycase Model AN-01P

Polycase Model AN-01P

Once you’ve found your ideal enclosure, it’s time to customize and order! We’ve made the process easier than ever so that you can get your enclosures to spec, on time and at a great price.

Ordering Your NEMA Weatherproof Enclosures from Polycase

One of our proudest achievements as a business has been streamlining our customers’ order process. You don’t have time to wait for quotes, deal with minimum orders or shop around for machining services—so why should you? Polycase has created the fast, easy, hassle-free way to get exactly the enclosure you need:

  • First, get a free quote in 90 seconds with our Quote Calculator.
  • Most of our products have no minimum order quantity, so it’s easy to try out as many as you need to find the perfect one.
  • We offer customized CNC machining and digital printing on most of our enclosures. It’s a smart and cost-effective option for high-performance customized enclosures.
  • Customized enclosures can ship in as little as one week. Simply provide us with the drawing or CAD file to get started.
  • Don’t need any modifications? All in-stock parts ship within one business day.
  • Our high-efficiency manufacturing process creates very little scrap, leading to less waste and lower costs for you.

Think of buying an electrical enclosure as if you’re purchasing a new home for some of your most important electronic assets. The enclosure you select will be their house for months, years or even decades. The nicer the house is, the more productivity, value and longevity you’ll get from your devices.

Of course, with that pressure on, the array of options, ratings and minute differences can seem impossible to grasp! But that’s where Polycase comes in—we’re here to help.

Polycase has over 65 years of experience in collaborating with our customers on weatherproof enclosure solutions. Through our extensive experience and deep product knowledge, we’ve helped thousands of customers create great things, and we’re not done yet. Contact us to learn more about Polycase’s leading selection of weatherproof NEMA enclosures!