What Does NEMA 13 Mean?

The NEMA enclosure ratings system is an essential tool that helps the designers of electrical and electronic devices select enclosures that offer the protection their devices need. Naturally, part of using the NEMA ratings system effectively is knowing what each rating means and identifying its key characteristics.

Polycase customers use NEMA ratings every day to ensure that they select the enclosures that most closely match their needs, so we provide guides to help our customers learn about the NEMA system and other topics of interest. In this article, we’ll examine the NEMA 13 enclosure rating, a common rating for indoor electronic enclosures. To get started, let’s quickly examine the basics of the NEMA system. 

What Are NEMA Ratings?

The NEMA ratings system was established by the National Electrical Manufacturers Association (NEMA) to rate the protective characteristics of an electrical or electronics enclosure. NEMA ratings evaluate an enclosure on the basis of its resistance to common environmental hazards (such as water or dust ingress) that an electrical device may encounter.

Each NEMA rating is a number or number-letter combination that corresponds to a specific set of protective standards. In many cases, a higher number means more protection, but this isn’t always true so be sure to check the specific standards of every rating carefully and compare them with any relevant electrical device design standards.

For more information on NEMA ratings, be sure to read Polycase’s NEMA ratings guide. Our TechTalk Blog also discusses many important aspects of the NEMA ratings system, including NEMA 12 enclosure FAQs, the differences between weatherproof NEMA enclosures and NEMA 3 vs. NEMA 3R enclosures. 

Defining the NEMA 13 Rating

The NEMA 13 rating is closely related to the more common NEMA 12 rating. Both NEMA 13 and NEMA 12 enclosures provide protection against:

• Accidental contact with hazardous or sensitive parts
• Ingress of circulating and floating foreign matter such as dust, dirt, lint, etc.
• Ingress of splashing or dripping water
• Ingress from non-corrosive oil and coolant seepage

However, NEMA 13 goes one step further than NEMA 12. NEMA 13-rated enclosures are also rated to provide protection against splashing and spraying of non-corrosive chemical agents such as oil and coolant. For this reason, you’ll often find NEMA 13 enclosures in environments such as machine shops and garages, where dripping and splashing of oil and coolant are perpetual concerns for sensitive devices. 

Note that although NEMA 13 is the highest number in the NEMA ratings system, it’s not actually the most protective rating. Next up, we’ll discuss what a NEMA 13 enclosure doesn’t do and which NEMA ratings to look at if you need a more protective enclosure. 

What a NEMA 13 Rating Doesn’t Protect Against

NEMA 13 enclosures generally don’t protect against outdoor weather conditions such as snow, rain, sleet, submersion in water or windblown dust. For these applications, you’ll want an outdoor enclosure such as a NEMA 3R enclosure or NEMA 6P enclosure. If you’re using the IP ratings scale, note that a NEMA 4 or 4X is the minimum that’s considered roughly equivalent to a dust proof IP rating. 

NEMA 13 enclosures are also not rated to protect against splashing or dripping of corrosive liquids. For corrosion protection, a NEMA 4X enclosure is a better choice. 

However, note that Polycase offers many NEMA 13-rated enclosures that meet more than one NEMA standard. As you’ll see, many of our NEMA 13 enclosures have also earned higher ratings like NEMA 3R, NEMA 4X and even NEMA 6P. 

NEMA 13 Enclosures from Polycase

If your project demands a NEMA 13 enclosure, Polycase has a wide selection to meet your needs. Our most popular NEMA 13 enclosures include: 

• Polycase AN Series: Our AN Series diecast aluminum enclosures are as rugged as they are elegant, and they’re rated all the way up to an ultra-tough NEMA 6P in addition to their NEMA 13 rating. 
• Polycase WA Series: Featuring some of our most popular and cost-effective indoor enclosures, the Polycase WA Series is created from durable flame-retardant ABS plastic and is rated for NEMA 13 and NEMA 4X enclosure performance. 
• Polycase ML Series: Polycase’s signature line of polycarbonate enclosures is designed for outstanding performance indoors and outdoors with NEMA 13 and NEMA 4X ratings. The ML Series of boxes are also available with a transparent cover for easy access and instrument reading. 

No matter what NEMA enclosure rating you need, Polycase can supply an enclosure that’s designed to perform. For more information, including quotes on customized electronics enclosures, call Polycase today at 1-800-248-1233 or contact us online.