NEMA 12 vs. NEMA 3R

It can be challenging to cut through the jargon and technical terminology when you’re looking for the right electrical enclosure. The question of NEMA 12 vs. NEMA 3R enclosures is one that might seem especially difficult at first. You might wonder what these terms mean and how to apply them when selecting an enclosure to protect your sensitive electrical and electronic equipment.

At Polycase, we always want to make it easy for our customers to find the enclosure that meets their needs perfectly. This quick guide to NEMA 12 enclosures and NEMA 3R enclosures will show you the key differences between these two enclosure ratings and explain which applications each is best for, and we’ll also explore a few of Polycase’s most popular enclosure options. 

A Quick Guide to NEMA Ratings

NEMA enclosure ratings have been developed by the National Electrical Manufacturers Association to identify and rate the protective qualities of electrical and electronics enclosures. Each number and letter combination specifies a certain level of protection against a certain combination of environmental hazards. 

For example, a NEMA 1 enclosure (the lowest rating) protects only against accidental contact from employees or tools. By contrast, a NEMA 6P enclosure (the highest rating) protects against prolonged submersion at a depth of up to six feet. 

It’s important to know that a numerically higher NEMA rating doesn’t always mean a higher degree of protection. The NEMA 12 rating, for example, provides less protection than the NEMA 3R. However, once you understand the particular specs of each rating, you can make informed decisions about which kind of enclosure is right for your application. 

What’s a NEMA 12 Enclosure?

NEMA 12 enclosures are among the most popular electrical enclosures for indoor applications. They’re a cost-effective solution for basic device protection in a normal commercial or light industrial environment. You’ll often find them used in applications such as control panels for security systems, lighting or machinery.

You can count on a NEMA 12 enclosure to provide protection from: 

• Accidental contact
• Light dripping and splashing of non-corrosive liquids
• Falling dirt 
• Settling airborne particles

NEMA 12 enclosures typically aren’t a good choice for an outdoor enclosure, since they don’t protect from outdoor weather conditions. Enclosure buyers may also want a higher level of protection for devices used in heavy industrial settings. However, many of Polycase’s NEMA 12 enclosures also have higher NEMA ratings in addition to their NEMA 12 ratings. 

What’s a NEMA 3R Enclosure?

NEMA 3R enclosures are designed to offer outdoor-rated performance at a cost-effective price point. They’re the most basic outdoor NEMA rating, suitable for everyday outdoor performance and weather protection. NEMA 3R enclosures are an especially popular option for electrical junction boxes. 

A NEMA 3R enclosure will provide protection from: 

• Rain, sleet and snow
• External ice formation
• Dripping and splashing liquids
• Falling dirt

If your device needs to withstand windblown dust and debris, repeated wash-downs with hose-directed water, corrosive environments or total submersion, you’ll need an enclosure with a higher NEMA rating. Check out our selection of NEMA 4X enclosures and NEMA 6P enclosures to learn about these tougher and more protective ratings—and remember that many of our NEMA 3R models also have other, higher NEMA ratings as well. 

NEMA 12 Enclosures and NEMA 3R Enclosures from Polycase

Polycase offers enclosures that span nearly the full range of NEMA enclosure ratings. Our catalog also includes several options that fulfill both the NEMA 3R and NEMA 12 standards, so you can get a higher level of protection at a cost-effective price point. Some of our popular options with NEMA 12 ratings and/or NEMA 3R ratings are: 

• Polycase ZQ Series: Rugged polycarbonate enclosures with tamper-resistant screw-on covers and a waterproof foam gasket. Available with many optional accessories such as DIN rail kits and pole mounting kits. (NEMA 3R and NEMA 12)
• Polycase SA Series: Our classic stainless steel enclosures, built to last featuring a hinged cover with a keyed latch for easy and secure access. (NEMA 12)
• Polycase WA Series: Polycase’s best-selling indoor enclosures, the WA Series is molded from durable and cost-effective ABS plastic. (NEMA 12)
• Polycase HD Series: Durable and attractive polycarbonate enclosures, created for outdoor-grade toughness featuring molded-on flanges for easy wall and surface mounting. (NEMA 3R and NEMA 12)

Customer service is what sets Polycase apart from other enclosure manufacturers, so don’t hesitate to reach out whenever you have questions about choosing the right enclosure. Call 1-800-248-1233 or contact us online to learn more–including information on our options for customized electrical enclosures.