Cracking the Code: NEMA vs. IP Ratings Demystified

If you frequently interact with heavy-duty electrical equipment, you must have seen a NEMA or IP rating on many of these devices. The ratings appear on both indoor and outdoor electrical enclosures, particularly those used in manufacturing and industrial plants.

But what do IP and NEMA ratings denote?

That question shall form the basis of this article. Read on as we introduce NEMA and IP before comparing the differences between these two popular rating standards.

What Is NEMA?

The National Electrical Manufacturers Association, more commonly abbreviated as NEMA, is a nonprofit organization that develops and publishes the technical standards for the manufacturing of electrical equipment as well as medical imaging machines.

NEMA is North America's largest trade association for electrical manufacturers. The Rosslyn, Virginia-based organization is probably best known for publishing the standards for electrical outlets and plugs used in US households.

Besides North America, NEMA also commands significant authority in South and Central America. The organization publishes its standards in special charts that spell out aspects like voltage and amperage that specific electrical equipment should have.

What Is IP?

Ingress Protection (IP), or more accurately, the IP code, is a code that indicates the extent to which an electrical device enjoys protection from water and dust.

IP codes are defined under the IEC 60529 standard of the International Electrotechnical Commission (IEC). This standard publishes guidelines on how well electrical enclosures and mechanical casings offer protection from water, dust, accidental contact, and intrusion.

Difference Between NEMA and IP Ratings

Both IP and NEMA ratings spell out the extent of protection a piece of electrical equipment has against external contaminants, such as water and dust. However, the two standards use different methods for testing and rating electrical enclosures.

An enclosure is a cabinet that houses electrical or electronic equipment. It’s mostly used in mounting electrical switches, knobs, or displays to prevent direct contact with the components as well as protect them from environmental agents.

The primary difference between NEMA and IP ratings is that IP typically covers protection against the ingress of water and solid objects like dust particles. On the other hand, NEMA covers corrosion resistance and hazardous atmospheric gases in addition to the ingress of water and solid objects.

Another difference between NEMA-IP ratings is that NEMA’s standards against environmental contaminants are mostly used for enclosures only, while IP ratings cover other electrical devices. Lastly, NEMA standards are common in North America, while IP standards apply internationally.

NEMA Ratings Examples

NEMA ratings for enclosures range from 1 to 13, depending on intended usage.

NEMA Enclosures Rated for Indoor Use

• NEMA 1 – Protects against entry of solid foreign objects.
• NEMA 2 – Protects against dripping or light water splashing.
• NEMA 4 & 5 – Protects against dust particles and light splashing.
• NEMA 11 – Protects against corrosion, dripping, liquid seepage, and certain hazardous gasses.

NEMA Enclosures Rated For Outdoor Use

• NEMA 3/3X – Protects against dust, rain, and ice.
• NEMA 3R/RX – NEMA type 3R and RX protect against dirt, rain, snow, and sleet.
• NEMA 4/4X – Offers all NEMA 3R/RX protection plus hose-directed water entry.

NEMA Enclosures Rated for Industrial Use

NEMA 12/12K

This protection covers dust particles, dripping, splashing, and rust. Twelve enclosures don’t have knockouts for conduits and cables, while 12K enclosures do.

A NEMA 12 vs. NEMA 4 comparison reveals that NEMA 12 provides better protection and is, therefore, more versatile.

NEMA 13

NEMA 13 is one of the most advanced NEMA types for enclosures. It offers the same protection as NEMA 12/12K, in addition to oil sprays or drips.

NEMA Enclosures for Hazardous Environments

• NEMA 7 – Covers explosions indoors.
• NEMA 8 – Covers explosions both indoors and outdoors.
• NEMA 9 – Covers ignition of combustible substances.
• NEMA 10 – Protects against methane-related hazards.

What Is NEMA 250?

NEMA 250 is a special NEMA standard for ingress protection of enclosures housing electrical components rated at 1000 volts or less. The enclosure may be mounted indoors or outdoors.

What Is NEMA 5-15R?

NEMA 5-15R is a NEMA rating for a standard 15-ampere electric outlet used especially in North America, Mexico, and Japan. The receptacle works with NEMA 5-15P plugs and is effective at handling both alternating current (AC) and direct current (DC). Its power consumption ranges from 15 amps at 125 volts to 50 amps at 250 volts.

NEMA 5-15R functions similarly to the NEMA 5 20R receptacle. Their core difference is in the amperage rating.

IP Ratings Examples

IP ratings are commonly represented by two digits.

The first digit (0 - 6) stands for the extent of protection an electrical equipment has from the ingress of foreign solid objects, particularly dirt and dust. The second digit (0 - 8) indicates the equipment’s protection from moisture ingress.

Below are the most common IP Ratings for enclosures;

• IP54 – Protects against limited dust and water spray in any direction.
• IP65 – Protects against dust and water projected from a nozzle.
• IP67 – Covers dust and immersion of 15 centimeters to 1 meter deep.
• IP68 – Covers dust and immersion.

Can You Convert Between NEMA And IP Ratings?

NEMA and IP systems use different variables to define the protection abilities of electrical equipment from environmental contaminants. That means the ratings have no direct relationship and, hence, are inconvertible.

It’s also worth noting that NEMA-rated equipment covers more aspects than their IP-rated counterparts. Therefore, IP enclosures aren’t always NEMA-compatible.

Summary

Both NEMA and IP provide reliable rating systems for electrical equipment. However, NEMA-rated appliances come with extra protection that makes them suitable for diverse environments.