NEMA 4X vs IP66 vs IP67: IP & NEMA Rating Comparison Chart for Electrical Enclosures

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If you are an electrical wholesaler or EPC purchasing agent, and you are frequently asked by customers "Do you have NEMA 4X?" or "Can IP67 replace NEMA 4X?", this article will help you clarify these questions:

1. What is IP level? — Detailed Explanation of IEC 60529 Dust and Water Resistance Codes

2. What is the NEMA type? — Detailed Explanation of NEMA 250 Protection Types

3. NEMA 4X vs IP66/IP67 — Why can't we just use the equal sign?

4. Understand in one picture — Quick Reference Table for IP to NEMA Correspondence

5. Procurement Selection Guide — Should the North American project use NEMA or IP?

This article was written by the BSUMWELL technical team. We are a manufacturer specializing in waterproof electrical enclosures, with products covering three major material series: PC/ABS plastic, stainless steel, and aluminum enclosures, with protection levels ranging from IP55 to IP68. We also support OEM/ODM customization.

1. IP vs NEMA: Why are they always confused? — The most common misconceptions in procurement

1.1 The customer says "needs NEMA 4X", the supplier says "we have IP67", can it be replaced?

This is a real-life scenario that plays out almost every month in the procurement industry:

The tender documents for the North American project stated that "Enclosure shall be NEMA 4X rated." The Chinese supplier glanced at it and replied, "Our product is IP67, which is a higher protection level than NEMA 4X and can completely replace it."

When the goods arrived at the site, the project inspector refused to accept them—because the IP67 certificate could not prove that the enclosure had passed the NEMA 4X corrosion resistance test and gasket aging test.

The root cause is that IP and NEMA are two different standard systems with different testing items, and cannot be directly converted.

IP only provides "dust and water resistance". NEMA not only provides dust and water resistance, but also... Corrosion resistant, freeze resistant, gasket aging resistant, and mechanical shock resistant. Even an IP67-rated enclosure can still rust and develop holes in a coastal environment if the material is not resistant to salt spray.

In this article, we will explain these two sets of standards clearly.

1.2 The fundamental difference between IP and NEMA – one only addresses "water and dust," while the other addresses "water and dust + corrosion + freezing + aging."

First, let's look at a comparison table:

Key conclusions:

• IP66 ≈ NEMA 4 — (Protective of wind and rain, and water spray), but NEMA 4 additionally includes tests for protection against ice and hose spray.

• NEMA 4X ≈ IP66 + corrosion resistant — The "X" in NEMA 4X stands for "Corrosion-Resistant," and it mandates compliance with the ASTM B117 salt spray test.

• IP67 ≈ NEMA 6(Protective of short-term immersion), but NEMA 6P additionally includes anti-corrosion requirements.

In short: NEMA 4X ≈ IP66 + corrosion resistance + icing resistance + gasket aging test. IP66 does not include corrosion resistance testing, so IP66 cannot be directly used to replace NEMA 4X.

Our stainless steel and aluminum housings are naturally corrosion-resistant and, according to test reports, meet NEMA 4X corrosion requirements. PC/ABS plastic housings are suitable for NEMA 4 applications.

[Understand the corrosion resistance of stainless steel/aluminum casings]

2. IP Classification Explained – Understanding Every Digit of the IP Code in One Image

2.1 IP Code Structure – What do the two numbers represent?

The format of the IP code is: IP address + first digit + second digit

• The first digit (0-6) — Dust protection rating. 0 = no protection, 6 = completely dustproof.

• The second digit (0-8/9) — Waterproof rating. 0 = no protection, 7 = short-term immersion, 8 = continuous immersion.

Quick reference for common levels:

Our products cover the full range from IP55 to IP68, and can be flexibly selected according to the project installation location and environment.

2.2 IP55, IP65, IP66, IP67, IP68 – Quick Reference Table for Procurement Selection

Our product line covers the following protection levels:

• IP55: Water-resistant – suitable for indoor electrical distribution boxes and outdoor installations with rain shelters.

• IP65: Water-resistant (stronger protection) - suitable for general outdoor wall installation.

• IP66: Resistant to strong water jets - Suitable for outdoor areas subjected to heavy rain and high-pressure washing.

• IP67: Prevents short-term flooding - suitable for low-lying areas with water accumulation and coastal typhoon areas

• IP68: Protected from continuous immersion – suitable for underwater equipment and environments requiring long-term immersion.

Materials include PC/ABS plastic, stainless steel, and aluminum casing, which can be flexibly selected according to project requirements.

[View the full range of IP55-IP68 waterproof housing products]

3. NEMA Type Explained – What exactly does the “X” in NEMA 4X represent?

3.1 NEMA Common Types Quick Reference Table

Our stainless steel/aluminum casing is suitable for NEMA 4X scenarios, while the PC/ABS casing is suitable for NEMA 4 scenarios.

[Check NEMA 4X compatible material products]

3.2 The "X" in NEMA 4X – corrosion protection is not an option, but a mandatory requirement.

• NEMA 4= Weatherproof and water-resistant (≈IP66)

• NEMA 4X= NEMA 4 +Corrosion resistance（“X” = Corrosion-Resistant）

NEMA 4X mandatory certification ASTM B117 Salt Spray Test (Standard method: 5% NaCl solution, continuous spraying at 35°C, typically no substrate corrosion after 200-500 hours). However...IP66 does not include salt spray testing.This is why IP66 cannot replace NEMA 4X.

Key Differences at a Glance: NEMA 4X vs IP66

Conclusion: NEMA 4X ≈ IP66 + corrosion resistance + anti-icing + gasket aging test. IP66 cannot replace NEMA 4X.

Our stainless steel housings come with material certification and salt spray testing support, meeting NEMA 4X requirements. Our aluminum housings, treated with a marine-grade coating, also offer excellent corrosion resistance.

4. NEMA 4X vs IP66/IP67: A diagram to understand the correspondence between IP and NEMA

IP vs NEMA Complete Correspondence Quick Reference Table

How do I use this table?

1. Confirm the required certification standards for the project (NEMA type or IP rating).

2. Locate the corresponding row in the table and check the "approximate corresponding IP/NEMA".

3. Pay attention to the "Core Test Differences" section—this is the key point that cannot be directly converted.

4. If you are unsure, please contact the technical team for assistance in assessing the situation.

Note: NEMA and IP cannot be precisely converted; they are only "approximately equivalent." The selection should be based on the certification standards required by the project.

4.1 IP vs NEMA Correspondence (Precise Conversion vs. Inaccurate Conversion)

The correspondence between NEMA and IP can only be "approximately" and cannot be precisely converted.

• IP20 → Roughly corresponds to NEMA 1

• IP24 → Roughly corresponds to NEMA 3R

• IP66 roughly corresponds to NEMA 4 (but NEMA 4 also includes tests for ice resistance and hose spray resistance).

• IP66 + corrosion resistant → roughly equivalent to NEMA 4X (but NEMA 4X additionally includes salt spray testing and gasket aging testing).

• IP67 + corrosion resistant → roughly equivalent to NEMA 6P (but NEMA 6P additionally includes anti-icing and anti-corrosion testing).

Key takeaway: When making a selection, prioritize the certification standards required by the project.For exports to North America, we can assist in providing the corresponding NEMA 4X materials and test documents.

4.2 Procurement Decision Flowchart – Three Steps to Determine Whether to Use IP or NEMA

Step 1: In which market is the project located?

• North America → NEMA priority

• Other → IP Priority

Step 2: In what environment is the project located?

• Coastal/Chemical Industry → Corrosion Protection Required → NEMA 4X or IP66+ Corrosion-Resistant Materials

• General outdoor use → IP65/IP66 or NEMA 4

Step 3: Will the installation location get wet?

• Yes → IP67/IP68 or NEMA 6P

• No → IP65/IP66 or NEMA 4

Our product line covers IP55-IP68, and the materials include plastic, stainless steel, and aluminum, which can be flexibly matched according to the project market and environment.

[View the full product range]

5. Frequently Asked Questions (FAQ) on Procurement

Q: Can IP67 replace NEMA 4X?

A：No. IP67 only tests for dust and water resistance (immersion in clean water), and does not include salt spray corrosion, gasket aging, or anti-icing tests. NEMA 4X has mandatory requirements in these areas.

Q: Which offers a higher level of protection, NEMA 4X or IP66?

A：They cannot be directly compared in terms of "higher" or "lower"—they test different items. IP66 only tests for dust and water resistance; NEMA 4X adds tests for corrosion resistance, ice resistance, and gasket aging in addition to dust and water resistance.

Q: My product has an IP67 test report. Can it be exported to North America?

A：For exports to the North American market, an IP67 test report is a plus, but it is usually insufficient to meet project acceptance requirements. North American engineering projects typically require UL certification (UL 50E) or NEMA type certification.

Q: Which IP ratings do your products cover?

A：Our products cover the following levels:

• IP55: Water-resistant (indoor/with rain shelter)

• IP65: Water-resistant (general outdoor use)

• IP66: Protect against strong water spray (outdoor heavy rain).

• IP67: Prevents short-term flooding (water accumulation in low-lying areas)

• IP68: Protection against continuous immersion (underwater equipment)

Materials include PC/ABS plastic, stainless steel, and aluminum casing.

[CheckPC/ABS plasticFull range of products]

Summary of the key points of this article

1. IP and NEMA are two sets of standards.—IP pipes are susceptible to water and dust accumulation, while NEMA pipes are susceptible to water and dust accumulation, corrosion, freezing, and aging.

2. NEMA 4X ≈ IP66 + corrosion resistant—IP66 cannot be directly used to replace NEMA 4X

3. A quick reference table to understand the corresponding relationships—But it cannot be converted precisely.

4. For North American projects, NEMA is the priority; for other markets, IP is the priority.

5. Our products cover IP55 to IP68.—Materials include plastic, stainless steel, and aluminum, allowing for flexible matching.

(Next article preview: Having learned the basics of IP and NEMA? Next, delve into the "de facto entry barrier" of the North American market—UL certification. Please read the second article in this series, "UL Certification Explained: UL 50E vs UL 508A—Certifications You Must Understand When Exporting to North America.")

[Contact the technical team for selection advice.]