What is an IP rating?
An IP (Ingress Protection) rating is a two-digit code defined by IEC 60529 (EN 60529) that tells you how well an enclosure resists the entry of solid objects and liquids. It replaces vague marketing terms like "waterproof" or "dustproof" with a precise, testable standard.
The code looks like IP66 or IP67. The first digit covers solids; the second covers liquids. A rating of IP66 means dust-tight (first digit 6) and protected against powerful water jets from any direction (second digit 6).
If a digit is replaced by X, for example, IPX7, it means that category was not tested, not that protection is zero.
How to read the IP code
| Position | What it covers | Range |
|---|---|---|
| First digit | Protection against solid objects and touch | 0 – 6 |
| Second digit | Protection against water / liquids | 0 – 9K |
| X (either position) | Not tested / not specified | , |
First digit, solid particle protection (0–6)
| Digit | Protection level | Typical use |
|---|---|---|
| 0 | No protection | Exposed components |
| 1 | Objects ≥ 50 mm (back of hand) | Large open equipment |
| 2 | Objects ≥ 12.5 mm (finger) | Standard indoor accessories |
| 3 | Objects ≥ 2.5 mm (tools, thick wire) | Older electrical enclosures |
| 4 | Objects ≥ 1 mm (fine wire) | Control panel enclosures |
| 5 | Dust-protected (limited ingress, no harmful deposit) | Factory control boxes |
| 6 | Dust-tight (complete, no ingress) | ATEX and outdoor enclosures |
A higher first digit includes all lower levels, an IP6X enclosure also meets IP5X, 4X, and so on. For hazardous area and outdoor electrical enclosures, you will almost always need digit 5 (dust-protected) or 6 (dust-tight).
Second digit, liquid ingress protection (0–9K)
| Digit | Protection | Test condition | Example uses |
|---|---|---|---|
| 0 | None | , | Indoor dry locations |
| 1 | Dripping water (vertical) | 1 mm/min rainfall, 10 min | Minimal condensation |
| 2 | Dripping water at 15° tilt | 4 positions, 10 min total | Covered outdoor |
| 3 | Spraying water up to 60° | Oscillating tube, 5 min | Outdoor lighting under eaves |
| 4 | Splashing water from any direction | 10 min, any direction | Outdoor outlets, garden lighting |
| 5 | Water jets (6.3 mm nozzle, 12.5 L/min) | 3 min, any direction | Outdoor junction boxes, IP65 cameras |
| 6 | Powerful jets (12.5 mm nozzle, 100 L/min) | 3 min, any direction | Ship deck equipment, IP66 enclosures |
| 7 | Immersion up to 1 m for 30 min | Submerged at 1 m depth | Outdoor connectors, rugged phones |
| 8 | Continuous immersion (depth specified by manufacturer) | Manufacturer-defined | Submersible pumps, underwater lighting |
| 9K | High-pressure hot water jets (80 °C, up to 100 bar) | Close-range, 10–15 cm | Food processing, steam cleaning, vehicle wash |
Common IP ratings and what they mean in practice
| Rating | What it means | Typical applications |
|---|---|---|
| IP20 | Finger-safe; no water protection | Indoor electronics, PC power supplies |
| IP44 | Objects > 1 mm; splashing water from any direction | Bathroom lighting, covered outdoor |
| IP54 | Dust-protected; splashing water | Sheltered outdoor control boxes |
| IP65 | Dust-tight; low-pressure jets | Outdoor cameras, junction boxes |
| IP66 | Dust-tight; powerful jets | ATEX terminal boxes, marine deck equipment |
| IP67 | Dust-tight; immersion up to 1 m / 30 min | Outdoor connectors, rugged smartphones |
| IP68 | Dust-tight; continuous immersion (depth per manufacturer) | Submersible pumps, underground junctions |
| IP69K | Dust-tight; high-pressure hot water jets | Food/dairy processing, truck wash |
For most outdoor electrical enclosures and ATEX installations, IP54 is the minimum spec, but IP66 is the premium specification from indEx Enclosures. IP68 is only necessary for continuous submersion applications.
IP ratings vs NEMA ratings
NEMA (National Electrical Manufacturers Association) ratings are the North American equivalent, but they are not directly interchangeable with IP ratings. NEMA covers additional factors that IP does not, corrosion resistance, icing, and hazardous atmospheres.
| NEMA type | Approximate IP equivalent | Key difference from IP |
|---|---|---|
| NEMA 4 | IP66 | NEMA 4 also covers ice formation |
| NEMA 4X | IP66 | NEMA 4X adds corrosion resistance |
| NEMA 6 | IP67 | NEMA 6 covers ice and brief submersion |
| NEMA 6P | IP68 | NEMA 6P covers prolonged submersion |
| NEMA 12 | IP52 | Indoor; limited dust and drip only |
If a project requires NEMA compliance (common in North America), specify the NEMA type explicitly, don't assume an IP-rated enclosure meets the full NEMA requirement just because the ingress numbers align.
Common misconceptions about IP ratings
Does a higher IP rating always include lower ratings?
For the first digit (solids), yes, IP6X covers everything below. For the second digit (liquids), no. An IP67 device (immersion tested) has not necessarily been tested to IP65 or IP66 (jet tested). The exposures are fundamentally different, submersion applies static pressure, jets apply dynamic pressure. Where both are required, specify a dual rating such as IP66/IP68.
Does IP68 mean a device can be used underwater indefinitely?
No. IP68 requires the manufacturer to define the specific depth and duration. One IP68 device might be rated for 2 m for 30 minutes; another for 5 m continuous. The standard sets the minimum test requirement; the manufacturer specifies the actual conditions. Always check the datasheet, not just the code. indEx iMTB range is IP68 certified up to 580×410×220 for depths of 3 metres deep, for a duration of 2 weeks.
Do IP ratings cover protection against all liquids?
No. IP water tests use fresh water under specific conditions. They say nothing about saltwater, solvents, oils, chemicals, or steam. An IP66 stainless steel enclosure in a chloride-rich marine environment may still suffer corrosion even though water cannot enter, the rating covers ingress, not material compatibility.
Does an IP rating guarantee permanent protection?
No. Gaskets and seals degrade over time, particularly in extreme temperature cycles or with chemical exposure. An IP66 enclosure that has not had its gasket inspected in several years may no longer meet its rating. ATEX enclosures require periodic inspection for exactly this reason.