Ingress Protection (IP) ratings define an enclosure’s ability to protect against environmental dust and water ingress. This standard of rating provides a way for both design engineers and consumers to determine how safe an enclosure is against foreign bodies.
Two of the most common IP ratings found on products today are IP66 and IP67. At first glance, both may offer seemingly identical levels of protection. However, because each digit in an IP rating corresponds to a different level of protection, it means they are not the same.
What Does an IP Rating Mean?
An IP rating represents one of the most common ways to rate an enclosure’s protective qualities. As defined by IEC 60529, this system was developed to grade the resistance of enclosures against the intrusion of liquids and solid particles.
An IP rating has two digits:
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- First Digit: Rated 0–6, indicating protection against solid objects and dust.
- Second Digit: Ratings go from 0 to 9, which represent the level of resistance against water ingress, from light condensation to high-pressure jets.
IP Rating First Digit Scale
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IP Rating Second Digit Scale
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IP66 Explained
With an IP66 rating, an enclosure is certified as dust-tight and capable of protecting against powerful water jets. During standard IEC testing, the housing withstands high-volume water streams delivered through a 12.5 mm nozzle at 100 liters per minute under 100 kPa pressure from all angles.
Common applications include:
- High-pressure washdown facilities (food processing, chemical plants)
- Heavy outdoor industrial equipment exposed to driving rain or sea spray
- Industrial automation control panels that get cleaned daily
Key Distinction: IP66 does not protect against submersion.
IP67 Explained
An IP67 rating ensures the enclosure is completely dust-tight and capable of withstanding temporary water immersion. It requires the sealed unit to prevent water ingress when submerged to a depth of 1 meter (approx. 3.3 feet) for a duration of 30 minutes.
Here are some of its applications:
- Underground vaults and utility chambers that are prone to flash flooding
- Trackside monitoring and tunneling controls exposed to pooled water
- Marine deck equipment facing temporary tidal wash-overs
Important Limitation: IP67 only applies to temporary immersion, not cover continuous submersion or high pressure. A NEMA 6P or IP68 specification is required for prolonged underwater applications.
| Feature/Standard | IP66 | IP67 |
| Solid Ingress Protection | Dust-tight (6) | Dust-tight (6) |
| Water Protection Type | High-pressure, powerful water jets | Temporary immersion in water |
| Testing Parameter | 100 L/min at 100 kPa from 3 meters | Immersion up to 1 meter for 30 minutes |
| Primary Risk Mitigated | Heavy directional washdowns, torrential rain | Flash flooding, pooling water, accidental drop |
| Submersion Rated? | No (Cannot handle standing water) | Yes (Temporary immersion under defined pressure) |
How to Choose Between IP66 vs. IP67
Neither IP66 nor IP67 is universally better because each rating shines under entirely different environmental demands. The right choice comes down to the specific physical hazards and environmental exposure your hardware faces in the field. Match your needs using the criteria below:
Choose IP66 when:
- Exposure is limited to rain, heavy splashing, or high-volume directional water streams.
- Routine high-pressure washdowns are part of the maintenance protocol.
- Standing water or submersion will not occur in the operating environment.
Choose IP67 when:
- Equipment is positioned in low-lying zones, subsurface pits, or flood-prone areas.
- Accidental short-term submersion (up to 1 meter for under 30 minutes) is a realistic risk.
- High-pressure, direct water jets are not present.
When to consider dual-rated or higher protection (IP67 / IP68 / NEMA 6P):
- The application encounters both high-pressure washdowns and standing floodwater.
- Submersion could extend beyond 30 minutes or depths greater than 1 meter—in which case stepping up to a NEMA 6P or IP68 standard is mandatory.
Specifying Enclosures for Electrical Systems
An IP rating only addresses half the protection equation. It won’t save your hardware from structural shock or signal interference. To ensure complete system reliability, evaluate these critical environmental and physical factors alongside their IP ratings:
- Material Compatibility: Will the housing resist chemical washdowns or salt spray corrosion? (e.g., 316 Stainless Steel vs. Aerospace Grade Aluminum).
- Mechanical Shock & Vibration: High vibration on transit or defense platforms can unseat basic gaskets if structural integrity isn’t built into the housing design.
- Electromagnetic Compatibility (EMC): Sensitive control platforms often require integrated RFI/EMI shielding in addition to environmental sealing.
The Factory-Integrated Advantage: Building Complete Systems
A common failure point in system integration occurs when contractors drill cable entries into standard off-the-shelf enclosures on-site. Remember that a waterproof enclosure is only as reliable as its weakest point. Field-modified cutouts frequently introduce leak points that degrade the seal.
At SLAYSON, we provide factory-modified, turnkey enclosure solutions. Starting with our commercial off-the-shelf (COTS) base units, our engineering team integrates precise accessories directly into the initial build:
- Welded In-Place Hubs: Factory-welded to guarantee permanent, watertight conduit entries.
- NPT Cable Glands & Cord Grips: Factory-matched to cutouts to preserve ingress ratings under pressure.
- Internal Mounting Plates & Swing-Out Panels: Customized layouts designed to fit your exact PCB or control hardware footprint.
- Optical Viewing Windows: Sealed observation ports allowing visual inspection without breaching the primary seal.
By utilizing our pre-engineered accessory ecosystem and MOTS (Modified Off-The-Shelf) services, engineers receive custom-configured enclosures backed by CAD models and engineering drawings to keep projects moving rapidly.
Explore our complete catalog of NEMA 6 and IP67 Enclosures to review technical datasheets and engineering specs.
Accelerate Your Design Cycle with SLAYSON
Specifying protective enclosures requires balancing environmental threats against system integration requirements. Whether your application demands protection against high-velocity washdown streams or static, standing water, SLAYSON delivers standard and modified off-the-shelf enclosures engineered to excel under both conditions.
When your projects require strict compliance, rapid customization, or reliable lead times, you can rely on our factory-integrated solutions to protect your vital electronics in the most demanding environments.
