NEMA 4 vs. NEMA 12: How Much Protection Do You Need? | Chatsworth Products
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NEMA 4 vs. NEMA 12: How Much Protection Do You Need?

(Tech Tips, Industrial Applications) Permanent link

RMR Enclosure Swing Wall-Mount Opened - RMR_SWING_WALLMT_P_OPENGRND_RGB72.jpgWhen it comes to electrical enclosures, knowing where it will be used and the level of protection required are two important considerations.

The National Electrical Manufacturer Association (NEMA) has established a scale from 1 to 13 to help identify which type of enclosure will best protect the enclosure and equipment inside.

However, selecting an enclosure with the wrong rating is one of the most common errors when specifying a NEMA enclosure. This can result in inadequate protection for equipment, leading to wasted time and money.

Two of the most commonly confused ratings are NEMA 4 and NEMA 12. Many customers assume they need NEMA 4 which has one of the highest levels of enclosure protection. However, the protection rating is so high that it may exceed the needs of the customer, resulting in unnecessary cost.

“If you're planning to support systems and technology equipment in an outdoor environment where you expect a downpour of water at any given time, or if it's directly exposed to the sunlight, then it’s recommended to deploy a NEMA Type 4 enclosure. If you plan on supporting equipment in a covered parking structure, dusty or dirty environment, or even a hot warehouse where minimal water is present, such as light splashing, then you can lead with a NEMA Type 12 enclosure,” Explains Sal Perez, Regional Sales Person for Chatsworth Products (CPI).

Key Differences  

  • NEMA 4
    • Common applications: Used to house standard IT networking connections and equipment, automation electronics or telemetry for non-corrosive and non-explosive processes like transportation signal controls, telecommunications phone and cable network distribution, communications signal equipment, and security equipment
    • Designed for both indoor and outdoor use
    • Used in applications where hosedown or pressurized streams of water occurs
    • Must provide protection against at least 65 GPM of water from a distance not less than 10 feet for 5 minutes
    • Protects against foreign solid objects (falling dirt, dust, lint, fibers and flyings)
    • External formation of ice on the enclosure will not damage the enclosure
    • Protects against rain, snow, sleet
    • Mechanism may not be operable when the enclosure is ice-covered
    • No protection against corrosive agents
  • NEMA 12
    • Common application: automation control and electronic drives systems, including packaging, material handling, non-corrosive process control, and manufacturing
    • Designed for indoor use
    • Used in applications where non-pressurized oil and water occurs (light drips and splashes)
    • Protects against non-hazardous foreign solid objects besides water
    • No protection against significant environmental risks (rain, snow, sleet, icing and spray of liquids)
    • No protection against corrosive agents

CPI's RMR Industrial Enclosures have been tested by UL, an industry-leading independent test laboratory, to carry the UL Type 12 listing and UL Type 12 listing for Canada. RMR Enclosures also carry UL classification to comply with IP55 per ANSI/IEC 60529, the international standard for degrees of protection for enclosures. Because both NEMA and IP standards are voluntary, meaning that any manufacturer can claim to have NEMA- or IP-rated products, it is important to check for a third-party tested UL Listing certification as well as the protection rating a product has.

To learn more about CPI’s industrial enclosures, click here.

Shannon Ryan, Digital Content Specialist

Posted by Shannon Ryan, Digital Content Specialist at 12/08/2016 02:15:02 PM


We need a NEMA 4 rated 84" cabinet with internal vertical cable management for project. Currently we've specified the Z4-21N-113C-C12 equipment cabinet for our project. Can you please assist or please direct me to the one whom can assist. Thanks.
Posted by: Mike Goodman at 1/9/2017 1:14 PM

Thank you for reaching out to us. Please call 1-800-834-4969 and one of our specialists will help you.
Posted by: Raissa Carey, Technical Writer at 1/9/2017 1:26 PM

Good morning,
Do you know about any State law that requires NEMA certification for equipment to be installed in US? Most States require compliance with NEC for installation design, but I cannot find any NEMA requirement for equipment certification/marking. I am wondering if an oversea IEC designed installation could be replicated, installed in US and insured against fire... Thanks.
Posted by: JEAN MARAVAL at 3/16/2018 7:45 AM


I do not know of any state laws and would not expect any requiring NEMA certification. NEMA provides standards for the construction of enclosures to provide a degree of protection for the equipment installed inside the enclosure but NEMA does not test or certify products. However, third party test agencies like UL and ETL independently test product to ensure they are compliant with the NEMA requirements. These are the certifications that municipalities may require for installations in their jurisdiction and they adopt them into their local building codes and regulations. The requirement would not be expected at the state level but the AHJ (Authority Having Jurisdiction) for most local municipalities would enforce this local code requirement. For the US market, UL, ETL, and CE Listings are common. Other international Listings are not recommended as the AHJ may not accept them. - Sam Rodriguez, Senior Product Manager
Posted by: Brittany at 3/20/2018 8:53 AM

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3/21/2019 4:44:04 PM